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There are 1570 search results for: Triangular Grids: A Review of Waveguide Analysis with Classical FIT and Some Reflections on Yee-like FIT- and FEM- Schemes



Title: Vector Hysteresis Modeling in Arbitrarily Shaped Objects Using an Energy Minimization Approach
Abstract: It is known that proper and efficient modeling of vector hysteresis is crucial to the precise design and performance estimation of electric power devices and magnetic recording processes. Recently, discrete Hopfield neural networks have been successfully utilized in the construction of vector hysteresis models. This paper presents a novel energy-minimization Hopfield neural network approach to implement Stoner-Wohlfarthlike vector hysteresis operators in triangular sub-regions. Advantages of the approach stem from the nonrectangular nature of such operators, which could mimic major hysteresis loops as well as their implementation in the most commonly used triangular discretization subdomains. Details of the approach are given in the paper.
Author(s): A. A. Adly, S. K. Abd-El-Hafiz
File Type: Journal Paper
Issue:Volume: 31      Number: 7      Year: 2016
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Title: Tunable Band-Notched UWB Antenna from WLAN to WiMAX with Open Loop Resonators using Lumped Capacitors
Abstract: The proposed antenna in this paper is compact UWB monopole antenna with a rectangular patch consists of stepped cuts and triangular slot. A two open loop resonators are designed and added near microstrip feed line to achieve sufficient band rejection from 5.1 GHz to 6.5 GHz for avoiding interference with WLAN frequency bands. The proposed antenna has low profile and compact size, its size equals 3.2 x 3.2 cm2. It has bandwidth from 3.1 GHz to 19.3 GHz with voltage standing wave ratio (VSWR) < 2, except the undesired band of 5.1–6.5 GHz. Two-lumped capacitors are inserted in order to investigate the ability of tuning the resonance frequency of the band-notched structures from 5.6 GHz to 3.5 GHz. Finally, the layout of the proposed UWB monopole antenna with the notched band is experimentally fabricated and measured to verify the simulation results. Furthermore, the return loss and far-field measurements of the fabricated antenna exhibit good match with simulation predictions.
Author(s): W. A. E. Ali, A. A. Ibrahim
File Type: Journal Paper
Issue:Volume: 33      Number: 6      Year: 2018
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Title: Triangular-Arranged Planar Multiple-Antenna for UWB-MIMO Applications
Abstract: A triangular-arranged (TA) planar multiple-antenna is proposed. It consists of three ultra-wideband (UWB) planar monopole antenna elements, with the centers and the ports of the elements arranged at the vertexes of two regular triangles, thus the polarization of each element is 120° different. The performance of the TA multiple-antenna is investigated by simulation and measurement, and the measured results agree with the simulated ones in reasonable precision. Within the ultra-wide bandwidth of 3.4 GHz – 12 GHz, the return loss at each port is better than 10 dB, and the isolation between any two ports is higher than 20 dB. Furthermore, good omni-directional radiation pattern is obtained over the interesting frequency band. A linear-arranged (LA) threeelement multiple-antenna is compared with the proposed TA antenna. Comparison between the TA antenna and the LA antenna validates the advantages of the proposed one, which consequently is suitable for UWB-MIMO applications.
Author(s): X.-S. Yang, S.-G. Qiu, J.-L. Li
File Type: Journal Paper
Issue:Volume: 29      Number: 1      Year: 2014
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Title: Triangular Patch Yagi Antenna with Reconfigurable Pattern Characteristics
Abstract: A pattern reconfigurable Yagi patch antenna is proposed. The antenna is composed of three triangular microstrip patches, i.e., one driven patch and two parasitic patches. By controlling switches, which are installed on the parasitic patches, the radiation pattern of the antenna can point to three different directions, covering an elevation range from -61° to +63° in the E-plane. The simulated and measured results are presented and they agree with each other in reasonable precision.
Author(s): J. Zhang, X. S. Yang, J. L. Li, B. Z. Wang
File Type: Journal Paper
Issue:Volume: 27      Number: 11      Year: 2012
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Title: Triangular Grids: A Review of Waveguide Analysis with Classical FIT and Some Reflections on Yee-like FIT- and FEM-Schemes
File Type: Conference Paper
Issue:Volume: Time Domain Numerical Modeling Beyond FDTD      Number:      Year: 2003
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Title: Triangular Grids: A Review of Resonator and Waveguide Analysis with Classical FIT and Some Reflections on Yee-like FIT- and FEM-Schemes
Abstract: Abstract—The focus of this paper is on the solution of Maxwell's equations on triangular orthogonal grids for timeharmonic elds in cylindrically symmetric resonators and general time dependant elds in length-homogeneous waveguides, respectively. The method is based on the Finite Integration Technique (FIT) [1], [2]. The 2D simulation on a structured triangular grid combines the advantages of FIT, as e.g. the consistency of the method or the numerical advantage of banded system matrices, with the geometrical exibility of noncoordinate grids. FIT on triangular grids was rst introduced in [3], [4]1. This paper presents a review describing the underlying theory in FIT operator notation rst introduced in [2] and puts this classical approach for FIT on triangular grids in relation to actual research in the eld.
Author(s): URSULA VAN RIENEN, URSULA VAN RIENEN
File Type: Journal Paper
Issue:Volume: 19      Number: 1      Year: 2004
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Title: Transmission through an Arbitrarily Shaped Aperture in a Conducting Plane Separating Air and a Chiral Medium
Abstract: The analysis of chiral materials has been an important subject in computational electromagnetics. In this paper, the method of moments technique is used to solve the problem of transmission through an arbitrarily shaped aperture separating air and a chiral medium. The aperture is in an infinite PEC (perfect electric conductor) plane. The excitation is assumed to be a plane wave in air. The equivalence principle is used to replace the aperture with a conducting surface with an equivalent magnetic current on each side of it. By enforcing the continuity of the tangential components of the total electric and magnetic fields across the aperture, coupled integral equations are obtained. The aperture has been modeled by triangular patches. The equivalent magnetic currents are approximated by linear combinations of expansion functions. The mixed potential formulation for a homogeneous chiral medium is used to obtain the electric and the magnetic fields produced by these expansion functions. The coefficients of these expansion functions are obtained by using the method of moments to solve the coupled integral equations.
Author(s): S. T. Imeci, F. Altunkilic, J. R. Mautz, E. Arvas
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
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Title: Transient Electromagnetic Scattering from Dielectric Objects Using Time-Domain Integral Equation
File Type: Conference Paper
Issue:Volume: Computational Techniques      Number:      Year: 2004
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Title: Transient Analysis of Electromagnetic Scattering using Marching-on-in-Order Time-Domain Integral Equation Method with Curvilinear RWG Basis Functions
Abstract: In this paper, a modified marching-onin- order time-domain integral equation method is utilized to analyze transient electromagnetic scattering from arbitrarily shaped objects. The spatial and temporal testing procedures are separate, and both of them are performed with the Galerkin’s method. The curvilinear RWG basis functions are used as spatial basis functions with curved triangular patch modeling. It gives a remarkable reduction to the number of unknowns, also the memory requirement and CPU time, without sacrificing the accuracy. The use of the weighted Laguerre polynomials as temporal basis functions ensures an absolutely stable solution even in late time. Several numerical results, including the single ogive and NASA almond, are given to demonstrate the accuracy and efficiency of the proposed method.
Author(s): Q. Q. Wang, C. Yan, Y. F. Shi, D. Z. Wang, R. S. Chen
File Type: Journal Paper
Issue:Volume: 26      Number: 5      Year: 2011
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Title: THE LINEAR-PHASE TRIANGULAR FACET APPROXIMATION IN PHYSICAL OPTICS ANALYSIS OF REFLECTOR ANTENNAS
Abstract: Numerical analysis of reflector antennas uses a discrete approximation of the radiation integral. The calculation replaces the actual reflector surface with a triangular facet representation. The physical optics current is then approximated within each facet. This paper provides analytical details of the method based on the assumption of a constant magnitude and linear-phase approximation of the physical optics current. Example calculations are provided for parabolic, elliptical, and shaped subreflectors. The computed results are compared with calculations made using a constant-phase approximation. These results show that the linear-phase approximation is a significant improvement over the constant-phase approximation in that the solution converges over a larger angular region of space. This improvement can significantly reduce storage requirements and possibly execution speed. [Vol. 6, No. 2, pp. 74-85 (1991)]
Author(s): W. A. Imbriale, R. E. Hodges, W. A. Imbriale, R. E. Hodges
File Type: Journal Paper
Issue:Volume: 6      Number: 2      Year: 1991
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Title: The Combination of GPU and CPU Techniques to Fast Calculate High Frequency Scattered Fields from 3-D Realistic Scatterers
File Type: Conference Paper
Issue:Volume: 10-TE-3 Recent Advances on Electromagnetics Modeling and Simulation Techniques II      Number:      Year: 2018
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Title: The analysis of transient scattering for rectangular incident waves using the discrete Laguerre transforms
File Type: Conference Paper
Issue:Volume: Higher Order Methods      Number:      Year: 2004
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Title: SURFACE MODELLING FOR EM INTERACTION ANALYSIS
Abstract: This paper deals with the numerical modelling of the surface of a structure with a wire grid or a surface patch for Electromagnetic (EM) interaction analysis. Surface currents and fields on a wire grid model are computed using the Numerical Electromagnetics Code (NEC). The results are compared with those obtained on a triangular surface patch model using an Electric Field Integral Equation (EFIE) formulation. Simple structures such as a square plate as well as complicated structures such as an aircraft are considered. Good agreement is obtained in most cases. [Vol. 6, No. 2, pp. 38-52 (l99l)]
Author(s): S. Kashyap, A. Loule, S. Kashyap, A. Loule
File Type: Journal Paper
Issue:Volume: 6      Number: 2      Year: 1991
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Title: Subdividing Distorted Prisms into Tetrahedra
File Type: Conference Paper
Issue:Volume: Finite Element Method and Applications      Number:      Year: 2003
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Title: Square Shape Patch Antenna with Triangular Slot
File Type: Conference Paper
Issue:Volume: S10 EM Simulations using Sonnet I      Number:      Year: 2017
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Title: Spherical Aperture-Coupled Antennas with Parasitic Element
Abstract: Theory and experiment of spherical aperture-coupled antennas with parasitic elements are presented in this paper. Current distributions on slot and conformal patches are calculated using spatial domain electric and magnetic Dyadic Green's Functions (DGFs). Electromagnetic fields for such a structure have been calculated with the aid of linear Rao-Wilton-Glisson (RWG) triangular basis functions and by converting spherical DGFs to Cartesian DGFs. In order to validate the proposed method, a prototype of this antenna is fabricated and tested. The effect of parasitic element on antenna characteristics such as gain and radiation pattern is investigated. Good agreement between the results shows accuracy and high convergence speed of the presented method.
Author(s): J. S. Meiguni, M. Kamyab, A. Hosseinbeig
File Type: Journal Paper
Issue:Volume: 27      Number: 12      Year: 2012
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Title: Slotted Triangular Monopole Antenna for UHF RFID Readers
Abstract: A new compact slotted triangular monopole antenna for ultra-high frequency (UHF) radio frequency identification (RFID) applications is presented. The antenna exhibits an omnidirectional radiation pattern and has a bandwidth (BW) of more than 13%. It covers the global UHF RFID band and has a maximum gain of around 2.6 dBi. An overview of the antenna design along with the full wave simulation is provided. A prototype of the antenna is fabricated and tested. Good agreement is obtained between simulated and measured results. Moreover, the antenna is used with a UHF RFID reader in real use cases where read range and read rate with different commercial tags are used to evaluate the antenna performance.
Author(s): K. ElMahgoub
File Type: Express Journal Paper
Issue:Volume: 1      Number: 1      Year: 2016
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Title: Slotted Triangular Monopole Antenna for UHF RFID Readers
Abstract: A new compact slotted triangular monopole antenna for ultra-high frequency (UHF) radio frequency identification (RFID) applications is presented. The antenna exhibits an omnidirectional radiation pattern and has a bandwidth (BW) of more than 13%. It covers the global UHF RFID band and has a maximum gain of around 2.6 dBi. An overview of the antenna design along with the full wave simulation is provided. A prototype of the antenna is fabricated and tested. Good agreement is obtained between simulated and measured results. Moreover, the antenna is used with a UHF RFID reader in real use cases where read range and read rate with different commercial tags are used to evaluate the antenna performance.
Author(s): K. ElMahgoub
File Type: Express Journal Paper
Issue:Volume: 32      Number: 12      Year: 2017
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Title: Slotted Triangular Monopole Antenna for UHF RFID Readers
Abstract: A new compact slotted triangular monopole antenna for ultra-high frequency (UHF) radio frequency identification (RFID) applications is presented. The antenna exhibits an omnidirectional radiation pattern and has a bandwidth (BW) of more than 13%. It covers the global UHF RFID band and has a maximum gain of around 2.6 dBi. An overview of the antenna design along with the full wave simulation is provided. A prototype of the antenna is fabricated and tested. Good agreement is obtained between simulated and measured results. Moreover, the antenna is used with a UHF RFID reader in real use cases where read range and read rate with different commercial tags are used to evaluate the antenna performance.
Author(s): K. ElMahgoubb
File Type: Journal Paper
Issue:Volume: 32      Number: 12      Year: 2017
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Title: SIMPLIFIED ANALYTICAL SOLUTIONS FOR MAGNETIC SIMULATION OF NEURONS
Abstract: Strong pulses of magnetic field are used to stimulate peripheral nerves and motor neurons in the cerebral cortex,. Such stimulation is used in neurology for numerous diagnostic purposes. The electric field induced in tissue along the neuron and its spatial derivative are the parameters determining neural response. Another important parameter influencing the efficiency of stimulation is the inductance of a coil producing the magnetic field, as it defines the current time derivative for a given pulse generator. For arbitrarily located coils of arbitrary shapes, a semi-analytical solution is presented to calculate spatial distributions of the electric field and its spatial derivatives in a semi-infinite tissue model. Analytical solutions are given for coils composed of linear segments parallel or perpendicular to the air- tissue interface. Expressions for inductance of coils having suitable geometries for neural stimulation are derived. Coils can be optimized for stimulation of nerves at given orientation and distance from the air-tissue interface. In the optimization, coil dimensions and shape are considered as they affect both the induced field and inductance. A quadruple coil consisting of triangular sections appears to offer some advantages over other shapes for stimulation of shallow nerves. For deep nerves spaces quadruple square and three-dimensional coils are preferred. Analyses described are useful in evaluating various options, gaining an insight into the physical phenomena involved, and as the first step before undertaking a numerical analysis of models more closely representing the tissue electrical and geometrical complexities. [Vol. 7, No. 2, pp. 162-178 (1992), Special Issue on Bioelectromagnetic Computations]
Author(s): Karu P. Esselle, Maria A. Stuchly, Karu P. Esselle, Maria A. Stuchly
File Type: Journal Paper
Issue:Volume: 7      Number: 2      Year: 1992
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Title: Simple and Efficient Design of Reconfigurable FSS with Triangular Patch Elements
File Type: Conference Paper
Issue:Volume: S13 Advances in EM Modeling and Optimization From Theory to Applications II      Number:      Year: 2017
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Title: Resolution of 2D Time Domain Electric Field Integral Equation: Novel formulation of RWG associated to Laguerre Polynomials
File Type: Conference Paper
Issue:Volume: S20 Integration Equation Techniques & Applications      Number:      Year: 2017
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Title: Receiver Sites for Accurate Indoor Position Location Systems
File Type: Conference Paper
Issue:Volume: Technologies for Ultra-Wideband Communication      Number:      Year: 2005
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Title: RCS Estimation of 3D Metallic Targets Using the Moment Method and Rao-Wilton-Glisson Basis Functions
Abstract: This work deals on the estimation of the radar cross section (RCS) of five three-dimensional conductive objects: the metallic sphere, NASA almond, single ogive, double ogive and conesphere, using the Moment Method. The Rao-Wilton-Glisson (RWG) basis functions were used to expand the surface current of targets inside the Electric Field Integral Equation (EFIE). Triangular domains of RWG basis functions were constructed using MATLAB tessellation capabilities and a MATLAB code was developed and run to solve the electromagnetic scattering problem. As a result five RCS graphs, one for each target, were obtained. The accuracy of the program was validated by comparing the obtained results with those reported in the Literature.
Author(s): G. K. Carvajal, D. J. Duque, A. J. Zozaya
File Type: Journal Paper
Issue:Volume: 24      Number: 5      Year: 2009
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Title: Preconditioning Effect of Multiple-Scattering-Based Macro Basis Function Approach
File Type: Conference Paper
Issue:Volume: Advanced Integral Equation Methods      Number:      Year: 2012
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Title: Performance analysis of MoM patch antenna simulations - RWG basis functions
File Type: Conference Paper
Issue:Volume: Advanced Computational Techniques for System Design      Number:      Year: 2003
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Title: Patch Antenna with Triangular Slitted Corners
Abstract: In this paper, a microstrip patch antenna with triangular slits was designed, simulated, fabricated and tested. The proposed patch antenna, with operating frequency of 9.5 GHz, is targeted. Simulation is carried out using Sonnet Suites. Antenna has 9.68 dB gain at 9.5 GHz with corresponding reflection coefficient of -19 dB. Proposed antenna introduces size reduction for patch antennas. The measurements of the fabricated patch antenna well corroborate the simulation results.
Author(s): A. Elakas, G. A. Irmak, M. Sencan, S. T. Imeci, T. Durak
File Type: Journal Paper
Issue:Volume: 34      Number: 2      Year: 2019
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Title: New Basis Functions for the Electromagnetic Solution of Arbitrarily-shaped, Three Dimensional Conducting Bodies Using Method of Moments
File Type: Conference Paper
Issue:Volume: MoM and Applications      Number:      Year: 2007
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Title: New Antennas Based on Triangular Patch as a Solution for RFID Application
Abstract: This paper covers the design of a new antenna for RFID applications at microwave frequencies. Five antennas are studied. The first three structures are inspired from a triangular patch, whereas the fourth and the fifth are inspired from a Sierpenski fractal antenna. The size reduction is more than 80%, which explains the utility of the proposed antennas.
Author(s): A. Ferchichi, N. Sboui, A. Gharsallah, H. Baudrand
File Type: Journal Paper
Issue:Volume: 25      Number: 3      Year: 2010
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Title: Multiband Multipolarized Planar Antenna for WLAN/WiMAX Applications
File Type: Conference Paper
Issue:Volume: S19 Finite-Difference Time-Domain Method: Theory and Applications      Number:      Year: 2015
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Title: Modeling of Surface Roughness Effects on the Performance of Rectangular u-Coaxial Lines
File Type: Conference Paper
Issue:Volume: Advances in Finite Element Technique and its Applications      Number:      Year: 2006
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Title: Modeling Corner Singularities in Triangular Cells with Hierarchical Bases
File Type: Conference Paper
Issue:Volume: Higher Order CEM: Development and Applications      Number:      Year: 2013
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Title: Miniaturized Microstrip Lowpass Filter with Ultra-Wide Stopband
Abstract: A new microstrip lowpass filter with compact size and ultra-wide stopband is presented. Using triangular patch resonators and butterfly resonator with four 45° radial “wing” patches, the introduced filter can successfully realize compact design and ultra-wide stopband. To further reduce the circuit size of the filter, the meander transmission lines are also adopted in the design. A demonstration filter with 3 dB cutoff frequency at 1.6 GHz has been designed, fabricated, and measured. Measured results show that the lowpass filter has an ultra-wide stopband bandwidth of 153.9 %, which is able to suppress the 11th harmonic response. Furthermore, it also has a small size of 14 ? 15 mm2, which corresponds to 0.114 ?g ? 0.122 ?g, where ?g is the guided wavelength at 1.6 GHz.
Author(s): Y. Dou, J. Wang, H. Cui, J. L. Li
File Type: Journal Paper
Issue:Volume: 28      Number: 7      Year: 2013
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Title: Microstrip Patch Antenna with Triangular Slits
File Type: Conference Paper
Issue:Volume: S57 Design Simulation and Build Microwave Devices using Sonnet Suites      Number:      Year: 2018
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Title: Low-Profile Broadband Top-Loaded Triangular Antenna with Folded Rim
Abstract: This paper presents the impedance matching technique and the bandwidth characteristics of a low-profile top-loaded triangular antenna with oblique shorting pins. The folded rim is arranged at the edge of the finite ground plane. The bandwidth diagrams for various antenna heights, finite sizes of the ground plane, and the widths of the folded rim are obtained through the moment-method simulation. The maximum bandwidth of 43 % is achieved with 0.05 ? height. For the low-profile configuration, the bandwidth of 17 % is obtained with 0.03 ? height.
Author(s): N. Michishita, W. J. Kim, Y. Yamada
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
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Title: Isosceles Right Triangular Waveguides
File Type: Conference Paper
Issue:Volume: 2-4-B Novel Antenna Design and Analysis Method for Remote Sensing and Other Related Applications      Number:      Year: 2017
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Title: Improper Integrals Calculations for Fourier Boundary Element Method
Abstract: This paper presents a method of regularization for the numerical calculation of improper integrals used in different formulations of Boundary Element Method (BEM). The main attention of the readers we would like to focus on Fourier Formulation of BEM. The singular integrals arise when for discretization the elements of a higher order than zero are used. Very often in the Diffusive Optical Tomography for infant head modeling, triangular or square curvilinear boundary elements of the second order are used [12,14], hence, our interest in the subject of effective and accurate calculation of singular integrals. Even for the classical formulation of BEM such a problem is extremely difficult [1]. Some authors believe that the practical application possesses only flat triangular boundary elements of zero-order, and although there is some truth in this statement, the elements of the second order show a significant advantage [10,12] in Diffusion Optical Tomography (DOT) for example. This issue becomes even more interesting when we deal with the Galerkin BEM formulation offering the possibility of matrix of coefficients symmetrisation, which has fundamental importance for inverse problems. This matter becomes critical when we start to consider the Fourier BEM formulation, introduced by Duddeck [5]. His approach provides the possibility of a solution in the case which has no fundamental solution. The light propagation, which is described by the Boltzmann equation (see Arridge [2]) is such a case. Currently and most commonly, the Boltzmann equation is approximated by the diffusion equation in strongly light scattering media [10]. In the author’s opinion, the problem of numerical integration of improper integrals has not yet been fully exhausted in the classic and Galerkin BEM formulation but the Fourier BEM formulation still expects the proposals of the effective solutions. Such an offer we would like to present in this paper.
Author(s): J. Sikora, K. Polakowski, B. Panczyk
File Type: Journal Paper
Issue:Volume: 32      Number: 9      Year: 2017
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Title: High-order Chebyshev-based Nystrom Methods for Electromagnetics
File Type: Conference Paper
Issue:Volume: S05 Locally Corrected Nystrom Method and its Applications      Number:      Year: 2021
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Title: High Frequency Radiation Pattern Analysis for Antennas Mounted on Material-Coated Conducting Platforms of General Shape
File Type: Conference Paper
Issue:Volume: Higher Order Methods      Number:      Year: 2004
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Title: Hierarchical Vector Basis Functions for Meshes with Hexahedra, Tetrahedra, and Triangular Prism Cells
File Type: Conference Paper
Issue:Volume: 30 Years of RWG Basis Functions      Number:      Year: 2011
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Title: Hierarchical Divergence-Conforming Basis Functions for Meshes with Hexahedra, Tetrahedra, and Triangular Prism Cells
File Type: Conference Paper
Issue:Volume: Advanced Integral Equation Methods      Number:      Year: 2012
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Title: Genetic-Algorithm Optimization of an Array for Near-Field Plane Wave Generation
Abstract: An alternative approach to the design of an array antenna to be used to generate plane waves in the near field is presented. The original array was designed on the basis of a triangular grid of seven elements arranged in a hexagon, to minimize the number needed to achieve approximately uniform illumination of the test zone, under the assumption of isotropic element radiation patterns. In the alternative approach, a genetic algorithm was used to discover more economical distributions of elements which could still generate acceptable approximations to a plane wave zone. It was found that considerable simplifications from the 'common sense' approach were possible.
Author(s): Neil N. Jackson, Peter S. Excell, Neil N. Jackson, Peter S. Excell
File Type: Journal Paper
Issue:Volume: 15      Number: 2      Year: 2000
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Title: Fast EM Scattering Analysis for the Hard Targets in a Layered Medium by Using the Hierarchical Vector Basis Functions
Abstract: This paper presents an efficient algorithm combining a higher order method of moments (MoM) with the adaptive cross approximation-singular value decomposition (ACA-SVD) algorithm for the threedimensional perfect electric conductor (PEC) targets located in a planar layered medium. An efficient set of hierarchical divergence-conforming vector basis functions based on curved triangular mesh is used to expand the induced surface electric current density on the metal surface of the target in layer medium. A three level discrete complex images methods (DCIM) is applied to efficiently obtain the closed form spatial Green’s functions. To be able to solve the electrically large problems, the ACA-SVD algorithm is proposed to accelerate the matrix-vector multiplication and reduce the memory requirements when the corresponding matrix equation is solved by a Krylov-subspace iterative method. The electromagnetic scattering from the practical model of hard targets buried in a lossy medium is analyzed in this paper, and numerical examples demonstrate the accuracy and efficiency of the proposed technique for the electrically large scattering problems in layered medium.
Author(s): L. Zha, R. Chen, T. Su
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Evaluation of the Contour Integral on Curved Edges in Time Domain Equivalent Edge Currents
File Type: Conference Paper
Issue:Volume: S03 Advances in Curved Patch Modeling      Number:      Year: 2019
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Title: EM Analysis of PEC Object above Halfspace by Using Higher-Order Hierarchical Vector Basis Functions
File Type: Conference Paper
Issue:Volume: 4-P4-A Electromagnetic Thoery and Computational Methods      Number:      Year: 2017
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Title: Electromagnetic Transmission Through an Aperture in a Conducting Plane Between Air and a Chiral Medium
File Type: Conference Paper
Issue:Volume: Guided Waves in Non-Standard Media      Number:      Year: 2008
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Title: ELECTROMAGNETIC SCATTERING BY AN ARBITRARILY SHAPED SURFACE WITH AN ANISOTROPIC IMPEDANCE BOUNDARY CONDITION
Abstract: The problem of electromagnetic scattering from arbitrarily shaped, imperfectly conducting surfaces that can be represented by an anisotropic impedance boundary condition is solved numerically using the electric field integral equation and a triangular patch model for the surface. The anisotropic impedance boundary condition function is described by a constant surface dyadic within each triangular face. The procedure is validated by comparison of numerical results obtained with the triangular patch model with body of revolution model results for problems involving scattering by spheres and cylinders having uniform or anisotropic impedance boundary conditions. [Vol. 10, No. 3 (1995), Special Issue on Advances in the Application of Method of Moments to Electromagnetic Radiation and Scattering Problems, pp 93-106]
Author(s): Allen W. Glisson, Mark Orman, Frank Falco, Donald Koppel, Allen W. Glisson, Mark Orman, Frank Falco, Donald Koppel
File Type: Journal Paper
Issue:Volume: 10      Number: 3      Year: 1995
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Title: Electromagnetic Coupling Analysis of Transient Excitations of Rectangular Cavity through Slot using TD-EFIE with Laguerre Polynomials as Temporal Basis Functions
Abstract: This paper presents an electromagnetic coupling analysis of transient waves excited a rectangular cavity containing an interior scatterer coupled to an external scatterer through a slot. Based on the equivalence principle, time domain integral equations are established by enforcing the boundary conditions on the internal and external scatterers, the slot and the cavity walls. The method of moments is applied in space and time domains to solve the developed system of integral equations. The unknown coefficients of the electric and magnetic currents are approximated by the triangular piecewise functions associated with Dirac function as space basis. To obtain accurate and stable solutions, the Laguerre functions are used as temporal basis. Numerical results involving the coupling effects between the cavity components are investigated. The numerical results are found to be in good agreement with EM theory and literature.
Author(s): D. Omri, T. Aguili
File Type: Journal Paper
Issue:Volume: 31      Number: 10      Year: 2016
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Title: Electric Field Distribution in a Biological Cell for Various Electrode Configurations-A Simulation Study
Abstract: Electroporation or electropermeabilization (EP) is a non-viral physical process of inducing and/or increasing permeability of biological membranes by the application of high intensity and short duration electrical pulses. The resulting high field strength in the membrane can lead to the formation of regions of increased permeability, often called pores that allow transmembrane transport of macromolecules, such as DNA and chemo drugs. The efficacy of EP depends on a number of parameters, such as electric field strength, duration, number of pulses, size of target cell, and type of drug or DNA to be fed, to mention a few parameters. While electric field strength, duration, and number of pulses are the dominant parameters for the electroporation effect, the electric field distribution also depends on the shape, the size, and the material of electrodes used. The various electrodes used in practice are the parallel plate electrodes, the needle electrodes, the needle array electrodes, and the caliper electrodes. Both six needle array and parallel plate electrodes were used in the skin cancer trials. The electric field distribution varies with the type of electrode. The choice of electrodes depends upon the type of application. For example, parallel plate electrodes produce good results in human clinical trials and the distance between the electrodes can be easily varied. Needle electrodes are the simplest, but due to their configuration, the field distribution is highly nonlinear; there is higher field strength around the needle tip. That is one of the reasons for using multiple needles or needle arrays to make the field distribution as uniform as possible. It is of practical interest to study the electric field distribution of various electrodes to make a more informed choice of which electrodes to use. This paper presents the results of a study of the electric field distribution in biological tissues for various electrode configurations. Magwel was used in this study. For the same voltage applied, the triangular and arc electrode configuration developed the highest electric field strength. Specifically, we develop simulation results that enhance or enable the acquisition of information from cells.
Author(s): M. O. Goni
File Type: Journal Paper
Issue:Volume: 27      Number: 5      Year: 2012
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Title: Efficient Time Integration Strategies for High Order Discontinuous Galerkin Time Domain Methods
File Type: Conference Paper
Issue:Volume: Finite-Volume and Discontinuous Galerkin Time-Domain Techniques      Number:      Year: 2008
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Title: Efficient Evaluation of the Logarithmic Singularity on Elongated Triangles With a 16 Nodes Polynomial Quadrature
File Type: Conference Paper
Issue:Volume: Recent Advances in Integral Equations and Fast Methods      Number:      Year: 2010
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Title: Design of a Planar UWB Antenna with New Band Enhancement Technique
Abstract: A planar antenna and a technique for enhancing its bandwidth for UWB applications have been proposed in this paper. The proposed antenna which has a compact structure and the total size of 30 × 22 mm2 consists of a square patch and a partial ground plane. Numerical study shows that the bandwidth of the proposed antenna can be controlled mainly by the patch size and width of the feeding line. The cutting triangular shape slots on the top edge of the ground plane help to increase the bandwidth by 43.6% (3.89 GHz). The measured -10 dB return loss bandwidth of the proposed antenna ranges from 2.95 GHz to 15.45 GHz which covers the entire UWB band. The nearly stable radiation pattern with a maximum gain of 5.9 dBi makes the proposed antenna suitable for being used in UWB communication.
Author(s): R. Azim, M. T. Islam, N. Misran
File Type: Journal Paper
Issue:Volume: 26      Number: 10      Year: 2011
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Title: Design and Analysis of EBG Antenna for Wi-Fi, LTE, and WLAN Applications
Abstract: A non-planar electromagnetic band gap (EBG) structured antenna is proposed in this paper for wireless communication applications. The proposed design consists of coplanar waveguide (CPW) fed square patch antenna embedded with triangular EBG backing on FR-4 substrate material for 2.4 GHz (Wi-Fi, LTE) and 5.2 GHz (WLAN) applications. Gain is improved from 2.8 dB to 13.9 dB by adding EBG structure in the proposed antenna and the parametric analysis is done for optimizing the antenna performance characteristics. The proposed antenna provides a maximum efficiency of 82.5% in the resonating frequencies. The prototyped antenna is having good correlation with the simulation results obtained from Finite Element Method (FEM) based Anyss-HFSS. High Frequency Structure Simulator is used to analyze the antenna parameters and the simulated and measured results are correlating well with each other with a slight change in frequencies.
Author(s): P. Bora, P. Pardhasaradhi, B. T. P. Madhav
File Type: Journal Paper
Issue:Volume: 35      Number: 9      Year: 2020
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Title: Compact W-Band Antipodal Fin-Line Transition from SIW to Rectangular Waveguide
File Type: Conference Paper
Issue:Volume: 4-1-C Passive/Active Microwave and Terahertz Devices      Number:      Year: 2017
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Title: Coalescing Tetrahedral TLM cells into Higher Order Elements for Improved Efficiency
File Type: Conference Paper
Issue:Volume: Recent Developments and Applications with Time-domain Modeling Techniques      Number:      Year: 2008
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Title: Blind Separation of Human Motions Based on Independent Component Analysis
File Type: Conference Paper
Issue:Volume: 1-P1-A Student Paper Contest      Number:      Year: 2017
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Title: Beyond RWG/Galerkin Solutions of the EFIE: Investigations into Pointmatched, Discontinuous, and Higher Order Discretizations
File Type: Conference Paper
Issue:Volume: 30 Years of RWG Basis Functions      Number:      Year: 2011
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Title: Barycentric Quadrilateral Basis on Triangular and Quadrilateral Meshes for Stable Surface Integral Equations
File Type: Conference Paper
Issue:Volume: Fast Integral Equation Methods and Stable Discretization      Number:      Year: 2013
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Title: Babinet’s Principle Applied to Distributed Arrays
File Type: Conference Paper
Issue:Volume: S15 Antenna Arrays and Applications      Number:      Year: 2020
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Title: Array Pattern Reconfiguration Using Pixel Method
Abstract: In this paper, the array elements are considered as pixels and their magnitude excitations are assigned to the values of 1 (i.e., active or turned ON) or 0 (i.e., inactive or turned OFF). Thus, each element either exists at its position in the considered array or not. The proposed pixel method can be applied to different planar array configurations such as square, rectangular, triangular, circular, or any other shape to achieve the required pattern reconfigurability. Moreover, by turning OFF some of the selected elements, the main beam of the array pattern can be switched to specify directions without using any phase shifters or any other RF components. Therefore, its practical implementation is simpler and cheaper than any other existing method. However, when comparing with arrays in which all their elements are turned ON, the gain of the considered arrays will be reduced when some selected elements are turned OFF. The array pattern reconfiguration using the pixel method has been designed and its parameters have been optimized using computer simulation Technology (CSTMWS), which uses the Finite Integration Technique (FIT). It’s also verified by High-Frequency Surface Structure (HFSS) commercial software (based on the FEM method). Numerical results obtained under fullwave modeling CST environment demonstrate the effectiveness of the described method.
Author(s): K. M. Younus, J. R. Mohammed
File Type: Journal Paper
Issue:Volume: 35      Number: 3      Year: 2020
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Title: Arbitrary Shaped Homogeneous Invisible Ground Cloak
Abstract: A general approach is introduced to design an arbitrary shaped invisible ground cloak with homogeneous constitutive parameters. The proposed homogenous ground cloak design method facilitates the fabrication process and achieves a variety of choices for choosing the cloak shape. In this approach, an arbitrary polygonal 2D cloak with any number of sides can be designed by dividing the polygonal cloak cross section into triangular segments and applying the proposed method on each one. The full wave simulations results confirm the idea performance, properly. Finally, a homogeneous ground invisible cloak for an object, which its contour is very similar to the lateral cross section of a car is designed and simulated to validate the capability and generality of the proposed idea.
Author(s): M. Fazeli, S. H. Sedighy, H. R. Hassani
File Type: Journal Paper
Issue:Volume: 31      Number: 11      Year: 2016
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Title: APPLICATION OF EQUIVALENT EDGE CURRENTS TO CORRECT THE BACKSCATTERED PHYSICAL OPTICS FIELD OF FLAT PLATES
Abstract: In the microwave case the physical optics (PO) method is frequently used for the analysis of complex structures which are modeled by flat plates of triangular or quadrangular shape. The study of the radar cross section (RCS) of an isolated panel, however, reveals deviations from experimental results which are due to edge diffraction effects not considered by PO. In order to correct the PO-field by an additive field term, the equivalent fringe currents (EC) of Michaeli have been used to derive the backscattering matrix of an isolated edge. By adding the matrices of the individual edges to the PO-matrix the RCS of a square flat plate with zero and finite thickness is analysed and the result is compared with measurements. The efficiency of the method is demonstrated for objects modeled by a higher number of panels and edges, namely a cylinder and a double dihedral. All computations were performed with the computer code SIG5 of the Institute. [Vol. 7, No. 1, pp. 24-47 (1992)]
Author(s): V. Stein, V. Stein
File Type: Journal Paper
Issue:Volume: 7      Number: 1      Year: 1992
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Title: Analyzing PEC Scattering Structure Using an IE-FFT Algorithm”
Abstract: In this paper a fast integral equation method, termed IE-FFT, is developed, analyzed and applied to the electromagnetic (EM) solution of scattering problems. The methodology is developed for the Method of Moments (MoM) solution of the Electric Field Integral Equation (EFIE) on electrically large Perfect Electric Conducting (PEC) structures. Similar to other Fast Fourier Transform (FFT) based algorithms, IEFFT uses a Cartesian grid to drastically decrease memory storage and speed up the matrix-vector multiplication. The IE-FFT algorithm employs two discretizations, one for the unknown current on an unstructured triangular mesh and the other on a uniform Cartesian grid for interpolating the Green’s function. The uniform interpolation of the Green’s function allows the fast computation of well-separated MoM interaction terms with the aid of a global FFT. Nevertheless, the coupling between near-interaction terms should be adequately corrected. The major contribution of this paper lies on the Lagrangian interpolation of the Green’s function. This not only allows simple and efficient algorithmic implementation, but also naturally suggests a rigorous error analysis of the algorithm. The efficiency of the method is based on the Toeplitz structure of the interpolated Green’s function. Therefore, it is applicable on both asymptotically-smooth and oscillatory kernels arisen in static and wave propagation problems, respectively. Through numerical simulations of electromagnetic wave scattering from a PEC sphere, the complexity of the IE-FFT algorithm is found to scale as O(N1.5) and O(N1.5logN) for memory and CPU time, respectively. Various numerical results verify the high accuracy and efficiency of the method.
Author(s): S. M. Seo, C. Wang, J. F. Lee
File Type: Journal Paper
Issue:Volume: 24      Number: 2      Year: 2009
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Title: Analytical Evaluation of Matrix Elements of Electromagnetic Integral Equations with RWG basis Functions for Arbitrarily Oriented Pairs of Triangular Surface Elements
File Type: Conference Paper
Issue:Volume: S51 Integral Equation Solvers for Real-Life Applications II      Number:      Year: 2018
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Title: Analysis of Transient Scattering From Conductors Using Laguerre Polynomials as Temporal Basis Functions
File Type: Journal Paper
Issue:Volume: 19      Number: 2      Year: 2004
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Title: Analysis and Synthesis of Equilateral Triangular Ring Microstrip Antenna using Support Vector Machine
Abstract: A support vector machine (SVM) based analysis and synthesis models are presented for the equilateral triangular ring microstrip antennas (ETRMAs) that operate at ultrahigh band applications. The analysis and synthesis of irregularly shaped microstrip antennas (MAs) require complex, lengthy and time consuming mathematical procedures and artificial intelligence techniques such as SVM eliminate great effort and time. In this paper, two models based on SVM are constructed for analysis and synthesis of ETRMAs. The number of 100 ETRMAs with various geometrical and electrical parameters (L, l, h and epsilon r) are simulated in terms of resonant frequency (fr) with the aid of an electromagnetic simulator program to obtain the data set. Two different SVM models are designed to obtain the resonant frequency and slot dimension of ETRMAs by using the simulation data set. The obtaining the resonant frequency and slot size are analysis and synthesis processes, respectively. The SVM models are trained with the simulated data set of 75 ETRMAs and tested with remainders 25 ETRMAs. A prototype of ETRMA is then fabricated to verify the proposed models in this paper. The testing results of the SVM are compared with the simulation/measurement results and the models are found to be successful. Antenna designers can use the proposed models quickly and simply in analysis and synthesis process of ETRMAs without the need for complex processes.
Author(s): A. Kayabasi
File Type: Journal Paper
Issue:Volume: 33      Number: 6      Year: 2018
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Title: An MoM Solution for Dielectric Rods of Arbitrary Cross-Section
File Type: Conference Paper
Issue:Volume: Guided Waves in Non-Standard Media      Number:      Year: 2008
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Title: An Irregular Ground Oriented Miniaturized Antenna for UWB Industrial Applications
Abstract: In this paper, a new small UWB antenna for different UWB industrial applications is presented. The proposed prototype comprises of a simple structure with a modified triangular patch and a sawtooth ground plane. The electrical size of the proposed antenna is 0.15lambda× 0.13lambda×0.014lambda, at lower end frequency. The patch and ground plane is optimized and analyzed. The antenna shows 116% of VSWR<2 impedance bandwidth from 2.8 to 10.5 GHz with a peak gain of 5.6 dBi and 75% of the average radiation efficiency. The proposed design established a nearly omnidirectional radiation characteristic over the operating frequency band. The proposed antenna was successfully simulated, prototyped, and measured. The uniqueness of the proposed antenna is the miniaturization of the antenna for the UWB frequency band, which can be applied for different portable and convenient UWB applications.
Author(s): M. Z. Mahmud, T. Alam, M. Samsuzzaman, A. Ullah, M. T. Islam
File Type: Journal Paper
Issue:Volume: 33      Number: 11      Year: 2018
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Title: An Efficient Finite-Element Time-Domain Method via Hierarchical Matrix Algorithm for Electromagnetic Simulation
Abstract: An efficient finite-element timedomain (FETD) method based on the hierarchical (H-) matrix algorithm is presented. The FETD method is on the basis of the second-order vector wave equation, obtained by eliminating one of the field variables from Maxwell’s equations. The time-dependent formulation employs the Newmark-beta method which is known as an unconditional stable time-integration method. H- matrix algorithm is introduced for the direct solution of a large sparse linear system at each time step, which is a serious handicap in conventional FETD method. H-matrix algorithm provides a data-sparse way to approximate the LU triangular factors of the FETD system matrix. Using the H-matrix arithmetic, the computational complexity and memory requirement of H-LU decomposition can be significantly reduced to almost logarithmic-linear. Once the H-LU factors are obtained, the FETD method can be computed very efficiently at each time step by the H-matrix formatted forward and backward substitution (H- FBS). Numerical examples are provided to illustrate the accuracy and efficiency of the proposed FETD method for the simulation of three-dimension (3D) electromagnetic problems.
Author(s): T. Wan, R. Chen, J. She, D. Ding, Z. Fan
File Type: Journal Paper
Issue:Volume: 26      Number: 7      Year: 2011
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Title: An Efficient 2D/3D Hybrid DGTD Transient Analysis for Arbitrarily Shaped Anti-Pads in Power-Ground Plate-Pair
File Type: Conference Paper
Issue:Volume: S18 Computational Electromagnetics Advanced Algorithms and Emerging Applications I      Number:      Year: 2017
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Title: Adding a Reproducible Airplane Model tothe Austin RCS Benchmark Suite
File Type: Conference Paper
Issue:Volume: S18 Numerical Methods: Validation, Errors and Accuracy      Number:      Year: 2020
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Title: Adding a Reproducible Airplane Model to the Austin RCS Benchmark Suite
Abstract: A full-size airplane model (the EXPEDITE-RCS model) was developed as part of a benchmark suite for evaluating radarcross- section (RCS) prediction methods. To generate accurate reference data for the benchmark problems formulated using the model, scale-model targets were additively manufactured, their material properties and RCS were measured, and the measurements were validated with a surface-integral-equation solver. To enable benchmarking of as many computational methods as possible, the following data are made available in a version-controlled online repository: (1) Exterior surface (outer mold line) of the CAD model in two standard file formats. (2) Triangular surface meshes. (3) Measured and predicted monostatic RCS data.
Author(s): J. T. Kelley, A. Maicke, D. A. Chamulak, C. C. Courtney , A. E. Yilmaz
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: A Wideband Circularly Polarized GNSS Antenna for Satellite Platforms
File Type: Conference Paper
Issue:Volume: S46 Physically Reconfigurable Antennas and Arrays: Design, Modeling and Materials II      Number:      Year: 2019
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Title: A STUDY OF TWO NUMERICAL SOLUTION PROCEDURES FOR THE ELECTRIC FIELD INTEGRAL EQUATION AT LOW FREQUENCY
Abstract: The numerical solution of the Electric Field Integral Equation (EFIE) using two different lowfrequency formulations is investigated. The two procedures are implemented for the triangular patch modeling procedure and results obtained for both methods are compared with the original triangular patch EFIE solution. The comparisons are made on the basis of the computed current values and the inverse condition number of the moment matrix. It is observed that the condition number of the matrix can be significantly different between the two low frequency formulations and that the method used to evaluate the forcing function can affect the results both in the low and high frequency ranges. [Vol. 10, No. 3 (1995), Special Issue on Advances in the Application of Method of Moments to Electromagnetic Radiation and Scattering Problems, pp 69-80]
Author(s): Wen-Liang Wu, Allen W. Glisson, Darko Kajfez, Wen-Liang Wu, Allen W. Glisson, Darko Kajfez
File Type: Journal Paper
Issue:Volume: 10      Number: 3      Year: 1995
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Title: A Straight-Forward Method of Moments Procedure to Solve the Time Domain Integral Equation Applicable to PEC Bodies via Triangular Patch Modeling
Abstract: In this work, a simple and straight-forward method of moments solution (MOM) procedure is presented to obtain the induced current distribution on an arbitrarily-shaped conducting body illuminated by a Gaussian plane wave directly in the time domain using a patch modeling approach. The method presented in this work, besides being stable, is also capable of handling multiple excitation pulses of varying frequency content incident from different directions in a trivial manner. The method utilizes standard Rao-Wilton-Glisson (RWG) functions and simple triangular functions for the space and time variables, respectively, for both expansion and testing. The method adopts conventional MOM and requires no further manipulation invariably needed in standard time-marching methods. The moment matrix generated via this scheme is a block-wise Toeplitz matrix and, hence, the solution is extremely efficient. The method is validated by comparing the results with the data obtained from the frequency domain solution. Several simple and complex numerical results are presented to validate the procedure.
Author(s): S. M. Rao
File Type: Journal Paper
Issue:Volume: 35      Number: 8      Year: 2020
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Title: A Simple Model to Compute Resonant Frequency of an Equilateral Triangular Patch Antenna Backed by Equilateral Triangular Cavity
File Type: Conference Paper
Issue:Volume: S38 EM Modeling and Applications - I      Number:      Year: 2021
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Title: A Second-Order Stabilized Control Volume Finite Element Method for Self-Heating Effects Simulation of Semiconductor Devices based on Triangular Elements
Abstract: A second-order control volume finite element method combined with the multiscale flux approximation (CVFEM-MS) based on triangular elements is proposed to numerically investigate the selfheating effects of semiconductor devices. The multiscale fluxes are combined with a selected set of second-order vector basis functions to stabilize the discretization of carrier continuity equations with respect to triangular elements. Numerical results reveal that the proposed method is robust and accurate, even on the mesh of low-quality, where the detrimental impacts caused by the severe self-heating on the terminal currents can be obviously observed for a bipolar transistor model.
Author(s): D.-M. Yu, X.-M. Pan, X.-Q. Sheng
File Type: Journal Paper
Issue:Volume: 36      Number: 5      Year: 2021
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Title: A Novel Switchable Double Band-Notch Antenna for Ultra-Wideband Application
Abstract: A novel microstrip-fed planar monopole antenna is proposed that is miniaturized in size and provides reconfigurable band-notch properties. The antenna's impedance bandwidth is 150% for VSWR < 2 across 2.6-18.3 GHz, thus satisfying FCC's frequency requirement for UWB systems defined between 3.1-10.6 GHz. To circumvent interference issues resulting from existing nearby communications systems within the UWB operating frequency, the antenna includes an inverted open-loop triangular slot embedded in the hexagonal shaped radiation patch to realize a band-notch response between 3.1 to 3.9 GHz necessary to reject the WiMax band, and open-end resonator structures at both sides of the patch to create a band-notch response between 5.1 to 5.9 GHz, thus enabling band rejection of WLAN and Hyperlink systems. Furthermore, it is demonstrated the band-notch can be electronically controlled without compromising the antenna's characteristic features. This is achieved by strategically located PIN diodes on the antenna.
Author(s): M. N. Moghadasi, S. F. Qotolo
File Type: Journal Paper
Issue:Volume: 29      Number: 10      Year: 2014
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Title: A Novel Ray Tracing Method of Creeping Waves on Triangular Mesh Surfaces
File Type: Conference Paper
Issue:Volume: 3-4-A Multi-Physics Modelling and Time-Domain and Frequency-Domain Computational Methods      Number:      Year: 2017
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Title: A Novel Domain Decomposition Method Decoupled Hybrid 2D/Q-2D Finite Element Method for Power/Ground Plate-Pair Analysis
File Type: Conference Paper
Issue:Volume: 3-MA-3 Advances in Numerical Modeling and Design      Number:      Year: 2018
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Title: A Novel Dielectric Loaded Vivaldi Antenna with Improved Radiation Characteristics for UWB Application
Abstract: In this paper, a compact (40×50×0.8mm3) Vivaldi antenna with trapezoidal corrugation and a triangular director element is proposed for high gain performance. The exponential slot with diamond slot stub is designed to broaden the bandwidth. The measured bandwidth is 11.3 GHz from 2.9 to 14.2 GHz under the condition of Voltage Standing Wave Ratio (VSWR) less than 2. The simulated gain is 5.5-9 dBi at the full bandwidth. The measured gain is 5-7.6 dBi from 3 to 5.8 GHz. In addition, the measured group delay of the proposed antenna is around 2±0.8 ns. The simulated and measured results agree well.
Author(s): H. Zhu, X. Li, L. Yao, J. Xiao
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: A New UWB Slot Antenna with Rejection of WiMax and WLAN Bands
Abstract: This paper presents a compact coplanar waveguide (CPW) fed ultra wideband (UWB) planar slot antenna with the characteristics of dual band rejection. The antenna consists of a rectangular slot with triangular tuning stub. The band notching of WiMax (3.2-3.8 GHz, with VSWR 68 at 3.5 GHz) is achieved by inserting a ‘U’ slot in the ground plane and band-notching of WLAN 802.11a (5.1-5.9 GHz, with VSWR 14 at 5.5 GHz) is obtained by embedding a ‘U’ type slot in the triangular tuning stub. The characteristics of the proposed antenna are studied both numerically and experimentally, and the design parameters for achieving optimal operation of the antennas are also analyzed extensively. The size of the antenna is around 28mm (L) × 21mm (W) × 1.6mm (T). The prototype of the proposed antenna is fabricated for its optimal values and tested. The VSWR, radiation pattern and gain are measured and agree well with the simulation results. The proposed antenna is simple, easy to fabricate and can be integrated into any UWB system, which can work without interference from WiMax, WLAN, and HYPERLAN/2 systems.
Author(s): J. William, R. Nakkeeran
File Type: Journal Paper
Issue:Volume: 25      Number: 9      Year: 2010
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Title: A Mortar Element Method for the Modelling of Scattering by Penetrable Objects
File Type: Conference Paper
Issue:Volume: Fast Integral Equation Methods and Stable Discretization      Number:      Year: 2013
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Title: A General Framework for Mixed Structured/Unstructured PEEC Modelling
Abstract: The paper proposes a re-formulation of PEEC modeling in terms of dual discretization of surface conductors. The result is a precise formalization of the PEEC tessellation and gives the possibility of handling general meshes, both structured and unstructured. This fact allows the use of triangular meshes only where necessary, leaving orthogonal discretization whenever possible and improving computational performances. The method, referred to as dual-PEEC, is validated by solving a structure referenced in literature and finally applied to the computation of the input impedance of a spiral inductor.
Author(s): F. Freschi, M. Repetto, F. Freschi, M. Repetto
File Type: Journal Paper
Issue:Volume: 23      Number: 3      Year: 2008
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Title: A General Framework for Mixed Structured/Unstructured PEEC Modelling
File Type: Conference Paper
Issue:Volume: Advanced EMC Modeling      Number:      Year: 2007
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Title: A Finite-Element Contrast Source Inversion Method for Microwave Tomography
File Type: Conference Paper
Issue:Volume: Efficient Solutions to Inverse Electromagnetic Problems      Number:      Year: 2010
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Title: A Comprehensive 2D FE-SIBC Model for Calculating the Eddy Current Losses in a Transformer Tank-Wall
Abstract: The calculation of the eddy-current losses is one of the most important aspects that must be considered in the design of transformers and electrical machines. In this paper, a comprehensive 2D finite element (FE) model for calculating the eddy-current losses in a tank-wall of the transformer is presented. The FE model takes into account the Surface Impedance Boundary Condition (SIBC). A detailed 2D-SIBC formulation in terms of the magnetic vector potential is described. The SIBC is incorporated into the FE formulation by using the Galerkin method. An axi-symmetric electromagnetic model of the transformer is solved by applying the SIBC formulation for calculating the loss intensity distribution along the vertical tank-wall. To demonstrate the validity of the SIBC formulation, the results are compared against those computed with a model based on first-order triangular elements. The advantages of using the SIBC formulation in the modeling of power transformers are highlighted.
Author(s): J. M. Díaz-Chacón, C. Hernandez, M. A. Arjona
File Type: Journal Paper
Issue:Volume: 27      Number: 8      Year: 2012
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Title: A Comparison Among Fast Visibility Algorithms Applied to Computational Electromagnetics
Abstract: This paper presents a set of fast algorithms developed for solving the visibility problem in large complex geometric scenarios. The implemented algorithms are: Binary Space Partitioning (BSP) –based on a binary tree structure- and three new ones: Trimming Method – facets which are partially occluded are trimmed –, Cone Method – a cone emerges from the point of view to discard shadowed facets – and Pyramid Method – a pyramid is used to eliminate non-lit patches – . All the proposed algorithms are tested on a pair of scenarios for determining the field of view of electromagnetic waves in order to calculate the corresponding induced currents on the surfaces. The scenarios consist of two electrically large spheres and two PEC plates respectively where the surfaces are meshed with a variable number of flat triangular patches. The first reflection contribution is calculated using Physical Optics (PO) for both cases. The results show that the computational time can be drastically reduced by assuming small percentage of error in the computed scattered fields.
Author(s): J. G. Meana, F. Las-Heras, J. Á. Martínez-Lorenzo
File Type: Journal Paper
Issue:Volume: 24      Number: 3      Year: 2009
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Title: A Compact UWB Printed Monopole Antenna with Triple-Band Notched Characteristics
Abstract: A compact triple band-notched printed monopole antenna for ultra-wideband (UWB) application is presented. By inserting two triangular-shaped notches in both sides of the ground plane of microstrip feed line, additional resonances are excited and the bandwidth is increased up to 160%. Three sharp notched frequency bands at 3.8 GHz, 5.5 GHz, and 7.5 GHz are achieved by embedding a pair of rectangularshaped slits in the ground plane and two pairs of modified bow-shaped slits in the patch. This novel monopole antenna has ultra-wide frequency bandwidth for input impedance, compact size (24 mm × 20 mm), low cost fabrication and Omnidirectional H-plane radiation pattern which makes it suitable for ultra-wideband applications. The measured results reveal that the presented triple band-notched monopole antenna is a promising candidate for UWB communication systems to avoid interference with WiMax band (3.3-3.7 GHz), some C-band (3.7-4.2 GHz), WLAN (5.15- 5.825 GHz) bands and some C-band satellite communication systems (7-8 GHz).
Author(s): A. Abdollahvand, A. Pirhadi, M. R. Hosseinnezhad, H. Ebrahimian
File Type: Journal Paper
Issue:Volume: 30      Number: 4      Year: 2015
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Title: A Compact High Gain Multiband Bowtie Slot Antenna with Miniaturized Triangular Shaped Metallic Ground Plane
Abstract: This paper presents a new compact, high gain and multiband planar bowtie slot antenna. The antenna structure comprises of dielectric substrate, copper conducting sheet, fillet triangular-shaped slots, and a chamfered metallic ground plane. The proposed antenna model is fed with the 50 Ω standard grounded coplanar waveguide (GCPW) feedline. The designed antenna is low profile with compact dimensions of 0.379λ×0.186λ×0.012λ at 2.39 GHz frequency. Stable multi-resonant behavior of frequencies is obtained with the material selection, slots dimensions and position. Moreover, the parametric study has been carried out in order to validate the frequency tuning mechanism and impedance matching control. The novelty of designed antenna lies in high performance features which have been achieved with ultra-compact (0.039λ×0.022λ) modified triangular shaped metallic ground plane. The proposed antenna is fabricated and experimentally verified. The antenna key features in terms of return loss, surface current distribution, peak gain, radiation efficiency and radiation patterns have been analyzed and discussed. The designed radiator exhibits the excellent performance including strong current density, peak realized gain of 6.3 dBi, 95% radiation efficiency, wide fractional bandwidth of 39.5% and good radiation characteristics at in-band frequencies. The simulation and measured results are in good agreement and hence make the proposed antenna a favorable candidate for the advanced heterogeneous wireless communication applications.
Author(s): Z. A. Dayo, Q. Cao, Y. Wang, P. Soothar, I. A. Khoso, G. Shah, M. Aamir
File Type: Journal Paper
Issue:Volume: 36      Number: 7      Year: 2021
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Title: A Compact Frequency Reconfigurable Split Ring Monopole Antenna for WLAN/WAVE Applications
Abstract: A novel frequency reconfigurable dual band monopole antenna based on the triangular split ring element is proposed for wireless communications. The antenna with an overall compact size of 25×25×1.6 mm3 is designed for the operating frequencies of wireless local area network (WLAN) 2.4/5.0 GHz standard and wireless access for vehicular environments (WAVE) 5.90 GHz standard. The parametric study is carried out for tuning the upper resonant frequency. The reconfigurability between the WLAN and WAVE frequency bands is achieved by using a pair of PIN diode. The design considerations for the proposed antenna are described and the experimental results are validated. The antenna exhibits almost uniform radiation characteristics and good gain at each frequency band with the -10 dB impedance bandwidth of 44.1%, 5.8% and 10.1% at 2.45/5.30/5.90 GHz WLAN and WAVE bands respectively.
Author(s): V. Rajeshkumar, S. Raghavan
File Type: Journal Paper
Issue:Volume: 30      Number: 3      Year: 2015
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Title: A Compact Design and New Structure of Monopole Antenna with Dual Band Notch Characteristic for UWB Applications
Abstract: In this paper, a compact design and new structure of monopole antenna with dual band notch characteristics for UWB applications has been presented. The antenna consists of a triangular patch with C-shaped slot, two L-shaped and one split ring shaped parasitic backplane elements structure. By inserting three slots in the rectangular truncated ground plane as defected ground structures (DGSs), much wider impedance bandwidth can be produced, and moreover to improve the input matching quality of the antenna at all its operating bands which are spread in a vast frequency range, a modified stepped feed-line is employed. These changes much improves the antenna’s impedance bandwidth by 112% which covers the entire UWB bandwidth range. In order to generate single band notch characteristic, split ring shaped parasitic element backplane structure is utilized on the ground plane side of the substrate. In addition, by etching a C-shaped slot on the radiating patch, a dual band notch function is achieved. The measured frequency results show an impedance bandwidth of 3.15-10.78 GHz for a Voltage Standing Wave Ratio (VSWR) less than 2 with two eliminated bands placed at 3.49-3.81 GHz (320 MHz, 8.8%) and 5.24-6.22 GHz (980 MHz, 17%), which reject the WiMAX band, and Wireless Local Area Network (WLAN) band, respectively. A prototype was fabricated and measured based upon optimal parameters and experimental results show consistency with simulation results. The measured radiation patterns of proposed antenna for most frequencies are omnidirectional and this antenna as wide impedance bandwidth.
Author(s): S. Hoseyni, J. Nourinia, C. Ghobadi, S. Masumina, B. Mohammadi
File Type: Journal Paper
Issue:Volume: 31      Number: 7      Year: 2016
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Title: A Broadband Reflectarray Antenna using the Triangular Array Configuration
Abstract: A novel broadband reflectarray cell element is designed for use in several offset-fed reflectarray antennas based on square and triangular lattice. The proposed double-layer element consists of two stacked rectangular patches having two slots in non-radiating edges. Reflection phase curves are obtained by changing simultaneously the slot’s length of top and bottom patch. The designed element exhibits a large phase-shift range in excess of 360o.This wideband cell element is designed to be used in a triangular lattice that eliminates the grating lobes for wideband reflectarrays composed of unit-cell larger than half-wavelength. Two 529-element square reflectarrays and two 518-element triangular reflectarray antennas were designed and simulated using CST and HFSS, for producing 20o and 35o off-broadside E-plane beams using a 20o offset feed. The 1-dB gain-bandwidth is about 30% at the center frequency of 14 GHz, and the maximum simulated gain is about 31 dBi which is equivalent to 51.5% aperture efficiency for a 20o off-broadside reflectarray based on triangular lattice configurations.
Author(s): M. Mohammadirad, N. Komjani, A. R. Sebak, M. R. Chaharmir
File Type: Journal Paper
Issue:Volume: 26      Number: 8      Year: 2011
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Title: 25 Years of Progress and Future Challenges in Higher Order Computational Electromagnetics
File Type: Conference Paper
Issue:Volume: 25 Years of Progress and Future Challenges in Applied Computational Electromagnetics II      Number:      Year: 2009
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Title: VERIFYING WIRE-GRID MODEL INTEGRITY WITH PROGRAM 'CHECK'
Abstract: A wire-grid model of a complex surface such as an aircraft consists of hundreds of "vertex" points joined by hundreds of wires or "links". A wire antenna analysis program such as NEC is used to find the currents on the wires. The formulation within NEC imposes restrictions on the geometry of the wires, which limit the length of "segments" compared to the wavelength, the radius compared to the wavelength, the ratio of the segment length to the radius, and so forth. This paper collects these limitations together into a set of "modeling guidelines". The"integrity" of a wire-grid is its ability to represent the electrical behaviour of the continuous surface that it models. An important aspect of integrity is conformance to the "modeling guidelines". Gross errors creep into complex grids: repeated wires, omitted wires, wires of zero length. More subtle errors which violate the "modeling guidelines" can lead to incorrect current distributions and misleading radiated or scattered fields form the wire-grid when solved with the NEC code. This paper describes a program called CHECK which examines an input geometry file for the NEC program for conformance to the "modeling guidelines" by each individual wire, by wires forming junctions, and by pairs which do not join but are closely spaced. CHECK tabulates "notes", "warnings" and "errors" to aid the user in assessing the degree to which the model satisfies the guidelines. CHECK systematically finds all the guideline violations in a model. CHECK produces lists of wires for display with computer graphics to show the location of each type of problem that CHECK finds. The guideline violations found by CHECK inherently suggest improvements that can be made to the wire-grid. [Vol. 5, No. 2. pp. 17-42 (1990)]
Author(s): C. W. Trueman, S. J. Kubina, C. W. Trueman, S. J. Kubina
File Type: Journal Paper
Issue:Volume: 5      Number: 2      Year: 1990
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Title: \"Introduction to Antennas\" – an antenna training DVD
File Type: Conference Paper
Issue:Volume: CEM for Applied Analysis and Synthesis      Number:      Year: 2005
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Title: \"Capacity estimation of HF ionospheric Channel\"
File Type: Conference Paper
Issue:Volume: Posters Session 2      Number:      Year: 2003
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Title: Zooming into the Near-fields: Embedding Generalized- and Pseudo-functions in the Solution Space of Maxwell's Equations
File Type: Conference Paper
Issue:Volume: Mathematical Aspects of CEM      Number:      Year: 2013
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Title: Z-diagonalized Planewave/FD Approach for Analyzing TE Polarized Waves in 2D Photonic Crystals
File Type: Conference Paper
Issue:Volume: FDTD Methods and Applications      Number:      Year: 2003
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Title: Yee-based 3D electromagnetic algorithm for discontinuous anisotropic dielectrics with global 2nd-order error
File Type: Conference Paper
Issue:Volume: Advances in Finite Difference Time Domain      Number:      Year: 2009
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Title: X-Band Linear Dielectric Resonator Antenna Array Fed by Dielectric Resonator Power Divider Array
File Type: Conference Paper
Issue:Volume: Advances in Phased Array Modeling      Number:      Year: 2012
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Title: X-Band Isoflux Concentric Circular Antenna Arrays for Image Data Download from LEO Satellites to Ground Stations
Abstract: A circularly polarized isoflux beam synthesized by concentric circular arrays of printed microstrip patch antennas is proposed for X-band transmission of image data from land-imaging LEO satellites to the ground stations. This beam has a wide coverage angle of about 100° of uniform illumination. The paper introduces a novel design of a compact righthand circularly polarized microstrip patch as an element for the concentric circular arrays. The patch antenna has impedance matching bandwidth of about 600 MHz and axial ratio bandwidth of about 170 MHz at 8.1 GHz. A prototype of the proposed patch antenna is fabricated for experimental measurements. The electromagnetic simulation and experimental results show good agreement. A computationally efficient particle swarm optimization (PSO) procedure is developed and applied to find the distribution of the excitation magnitudes over the array elements so as to generate an isoflux beam in all the elevation planes with circular symmetry in the azimuth planes. The phase of excitation is the same for all the array elements. The method proposed to apply the PSO reduces the computational resources to about 6.5% of those required by the conventional method of application. Moreover, the proposed iterative PSO procedure is shown to be very fast convergent.
Author(s): M. A. El-Hassan, K. F. A. Hussein, A. E. Farahat, K. H. Awadalla
File Type: Journal Paper
Issue:Volume: 34      Number: 11      Year: 2019
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Title: Wrapping Existing Electromagnetic Code into an Object-Oriented Scripting Programming Language
File Type: Conference Paper
Issue:Volume: Object Oriented Computational Electromagnetics      Number:      Year: 2006
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Title: WLP-FDTD Implementation of CFS-PML for Plasma Media
File Type: Conference Paper
Issue:Volume: S19 Finite-Difference Time-Domain Method: Theory and Applications      Number:      Year: 2015
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Title: WLAN Based Indoor Positioning in Building Halls by Using Trilateral
File Type: Conference Paper
Issue:Volume: S23 RF/Microwave Electromagnetics - Computational Modeling and Experiments      Number:      Year: 2015
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Title: Wireless Propagation in Non Line of Sight Urban Areas using Uniform Theory of Diffraction
Abstract: This paper describes a three-dimensional electromagnetic propagation model for signal power prediction in a non line of sight urban area located in Singapore. The model, which is implemented using the Ohio State NEC-BSC V4.2 basic scattering code and is based on ray theory and uniform theory of diffraction (UTD) takes into account first, second, and third order effects including triple reflections and diffractions. The simplified propagation model of Raffles Place, the central business district of Singapore, uses more than 360 geometrical structures and is compared with data measured at 937.6 MHz along a drive route at the site. The results from the propagation model produced reasonable agreement with the measurements showing that a simplified model using UTD can be used to simulate the gross features of electromagnetic scatter in an urban area. It is shown that use of penetrable dielectric building walls are also necessary for accurate prediction of radio wave propagation in urban areas under non line of sight conditions. It is also found that third order scattering effects can be dominant in non line of sight situations and may be necessary for accurate predictions.
Author(s): G. A. Ellis, G. A. Ellis
File Type: Journal Paper
Issue:Volume: 18      Number: 3      Year: 2003
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Title: Wireless Power Transfer via Negative Permittivity Metamaterials as Resonating Elements
File Type: Conference Paper
Issue:Volume: S42 Wireless Power Transfer      Number:      Year: 2017
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Title: Wireless Power Transfer Using Magneto-Electric Dipoles
File Type: Conference Paper
Issue:Volume: S37 Wireless Power Transfer and Energy Harvesting: Advances in Modelling and Practice      Number:      Year: 2019
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Title: Wireless Power Transfer to Closely Coupled Loop Antennas Embedded in Concrete for Sensing
File Type: Conference Paper
Issue:Volume: Wireless Powering of Devices & Energy Harvesting      Number:      Year: 2014
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Title: Wireless Energy Harvesting Using a Negatively Charged UV Antenna
File Type: Conference Paper
Issue:Volume: 3-3-D Wireless Power Transfer and Harvesting      Number:      Year: 2017
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Title: Wireless Communication Applications of the Continuous Transverse Stub (CTS) Array at Microwave and Millimeter Wave Frequencies.
File Type: Conference Paper
Issue:Volume: Phased Array and Active Antennas      Number:      Year: 2005
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Title: Wireless Communication Antennas: Special Requirements And New Designs of Dielectric Resonator Antenna
File Type: Conference Paper
Issue:Volume: Poster Sessions 1      Number:      Year: 2007
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Title: Wireless Body Area Networks: UWB Antenna design and Channel Modeling
File Type: Conference Paper
Issue:Volume: S19 Biomedical Applications      Number:      Year: 2020
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Title: WIREGRID: A NEC2 PRE-PROCESSOR
Abstract: WIREGRID is a pre-processor for the widely used public domain method of moments computer code NEC2. WIREGRID was developed for modelling metallic structures using a mesh of wires. In particular, it has powerful facilities for controlling the density of the mesh, permitting the same basic model to be used for different frequencies, with the code automatically generating a suitable mesh for a particular frequency. WIREGRID is not limited to generating wire meshes: it can also be usefully applied to true thin-wire modelling, for instance for Yagi-Uda and log-periodic antennas. In this paper, the basic philosophy of the code is described, and the code capabilities are detailed. Sufficient detail is presented so that the paper can serve as a reference for code users. The meshing algorithm is briefly described. An example is shown of the automatic mesh generation capabilities applied to an automobile. WIREGRID is available in the public domain via anonymous ftp; details of the ftp sites and hardware requirements are given in the appendices. [Vol. 10, No. 1 (1995), pp 31-39]
Author(s): C. F. du Toit, D.B. Davidson, C. F. du Toit, D.B. Davidson
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
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Title: WIRE-GRID MODELING OF SLOT ANTENNAS
Abstract: The ability of a computer code to model slot antennas is investigated. A comparison of experimental and numerically calculated antenna data is presented. [Vol. 1, No. 1, pp.6-14 (1986)]
Author(s): Jimmy L. Funke, Jimmy L. Funke
File Type: Journal Paper
Issue:Volume: 1      Number: 1      Year: 1986
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Title: Wire Realization of a Tapered Slot Antenna with Reconfigurable Elements
File Type: Conference Paper
Issue:Volume: Electromagnetic Simulation using FEKO      Number:      Year: 2011
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Title: Wire Grid Moment Method (NEC) Models of a Patch Antenna
Abstract: Wire grid models of an air-loaded resonant circular patch antenna are used to calculate several observable quantities. The resonant frequency, input reactance, and bandwidth are accurately calculated, but the input resistance is underestimated by the grid models due to the existence of separate currents on both the top and bottom of the measured solid patch. The Lawrence Livermore (NEC3) Method of Moments computer program was used to generage the grid models. Averge wire lengths of about 0.03 wavelengths are required for accurate results. A comparison with other studies suggests that the 0.03 wavelength segmentation may be required because the patch is close to the ground plane (0.0175 wavelengths), and/or because errors in the near field calculation are compounded by the large fraction of energy stored in the near field since the patch is a high Q resonator.
Author(s): P.G. Elliot, S.T. McBride, P.G. Elliot, S.T. McBride
File Type: Journal Paper
Issue:Volume: 4      Number: 3      Year: 1989
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Title: Wire Fault Diagnosis Using Time-Domain Reflectometry and Backtracking Search Optimization Algorithm
File Type: Conference Paper
Issue:Volume: S43 Inverse Finite Element Optimization in Electromagnetic Product Design and Non-Destructive Evalutation II      Number:      Year: 2015
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Title: Wire Fault Diagnosis Based on Time-Domain Reflectometry and Backtracking Search Optimization Algorithm
Abstract: The development of a robust and accurate fault diagnosis approach under various system and fault conditions is a research area of great interest. The objective of this paper is to develop a new non-destructive approach for wiring diagnosis based on Time Domain Reflectometry (TDR) in one hand and on Backtracking Search Optimization Algorithm (BSA) in the other hand. Real-world case studies are investigated to demonstrate the effectiveness and robustness of the proposed approach. Simulation results evaluated from experimental data demonstrate that the proposed approach can be used for effective diagnosis of complex wiring networks.
Author(s): H. Boudjefdjouf, H. R. E. H. Bouchekara, F. de Paulis, M. K. Smail, A. Orlandi, R. Mehasni
File Type: Journal Paper
Issue:Volume: 31      Number: 4      Year: 2016
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Title: WIPL-D Results and Time Domain Response for an Impulse Radiating Antenna (IRA)
File Type: Conference Paper
Issue:Volume: Special Session: Electromagnetic Modeling by WIPL-D      Number:      Year: 2005
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Title: WIPL-D Results and Time Domain Response for an Impulse Radiating Antenna (IRA)
File Type: Conference Paper
Issue:Volume: Special Session: Electromagnetic Modeling by WIPL-D      Number:      Year: 2005
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Title: WIPL-D Parallelization Effort
File Type: Conference Paper
Issue:Volume: Special Session: Electromagnetic Modeling by WIPL-D      Number:      Year: 2005
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Title: WIPL-D Optimization of a Harmonic RF Tag
File Type: Conference Paper
Issue:Volume: EM Applications Using WIPL-D      Number:      Year: 2013
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Title: WIPL-D Model and Simulation Results for a 6ft Diameter Impulse Radiating Antenna (IRA)
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D Software      Number:      Year: 2006
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Title: WIPL-D Compared to Other EM Codes for the Analysis of Printed Antennas
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling by WIPL-D Code      Number:      Year: 2003
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Title: WIPL Code Validation for Metallic Structures
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling by WIPL-D Code      Number:      Year: 2003
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Title: Wind Turbine RCS Modeling and Validation*
File Type: Conference Paper
Issue:Volume: Topics in Radar Scattering      Number:      Year: 2011
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Title: Wind Power Axial-Flux PM Generator Loss Computation Using Quasi-3D FEA
File Type: Conference Paper
Issue:Volume: S07 Low Frequency Magnetics      Number:      Year: 2016
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Title: Wideband, Scanning Array for Simultaneous Transmit and Receive
File Type: Conference Paper
Issue:Volume: S19 Broadband Antennas and Applications      Number:      Year: 2018
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Title: Wideband Single Arm Spiral Antennas
File Type: Conference Paper
Issue:Volume: S14 EM Modeling using FEKO - II      Number:      Year: 2021
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Title: Wideband Self-adjoint Jacobian Computation with Time-domain Field Solutions
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling with QuickWave/Concerto      Number:      Year: 2008
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Title: Wideband Quasi-Yagi Antenna with Broad-Beam Dual-Polarized Radiation for Indoor Access Points
Abstract: This paper presents a wideband, broad beamwidth, dual-polarized antenna for the indoor access points. Its primary radiating elements are two quasi-Yagi antennas, which are arranged orthogonally. The antenna element employs two balanced directors to broaden bandwidth and avoid the structural conflict of the orthogonal installation. A microstrip-slotline transformer is used in the feeding structure for allowing the wideband operation and high port-to-port isolation. The dualpolarized quasi-Yagi antenna is incorporated with a metallic cavity in order to improve the unidirectional radiation in terms of gain, front-to-back ratio, and beamwidth. The final prototype has been fabricated and tested. The antenna yielded a wide impedance bandwidth covering a frequency range from 1.64 to 3.0 GHz (60%) for both ports with port-to-port isolation of a higher than 25 dB. In addition, at both ports, the antenna achieves stable unidirectional radiation with broad beamwidth, high front-to-back ratio, and high radiation efficiency.
Author(s): S. X. Ta, C. D. Bui, T. K. Nguyen
File Type: Journal Paper
Issue:Volume: 34      Number: 5      Year: 2019
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Title: Wideband Printed Lotus Antenna
File Type: Conference Paper
Issue:Volume: Wideband Antennas      Number:      Year: 2005
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Title: Wideband Printed CPW-fed Binomial Curved Slot Antennas
File Type: Conference Paper
Issue:Volume: Antenna Modeling and Small Antennas      Number:      Year: 2008
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Title: Wideband Power Divider Using Novel Split-Ring Resonator
Abstract: A set of novel split-ring resonator basic block Hybrid-Microwave Integrated-Circuit (HMIC) components (transmission line, open and short stubs) is presented with applications to the RF/Microwave power divider. This new open and short LH HMIC resonators have compact sizes of 0.81 and 1.44 mm2 , respectively. The prototypes of an LH power divider constructed from these basic components have been designed, fabricated, and characterized. The LH power divider including two LH branches shows equal power split from 1 to 7 GHz. The proposed power divider benefit from the miniaturized LH HMIC components and have compact sizes of 2.205 mm2 , respectively. There is a good agreement between the full-wave simulations and measurement results with 0.254-mm thick RT5880 substrate. While maintaining similar performance, a 50% reduction in impedance transformer is achieved in comparison to a conventional design.
Author(s): T. Huang, D. Jiang, H. Hu
File Type: Journal Paper
Issue:Volume: 30      Number: 2      Year: 2015
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Title: Wideband Planar Slot Antennas
File Type: Newsletter Paper
Issue:Volume: 19      Number: 1      Year: 2004
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Title: Wideband Open Sleeve Dipole Antenna
File Type: Conference Paper
Issue:Volume: S45 UWB and Multi-Band Antennas II      Number:      Year: 2016
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Title: Wideband Octagonal Dual Circularly Polarized Sub-array Antenna for Ku-Satellite Systems
Abstract: In this paper the analysis and design of a dual circularly polarized 4×4 antenna array operating in Ku-band are discussed with emphasis on its sequential feeding network. The dual circular polarization is achieved by feeding a stacked octagonal patches with a wideband branch line coupler. The proposed 4×4 antenna array is based on two separate sequential feeding networks for LH and RH circular polarizations. The advantage of the proposed feeding network is that it is implemented on a single layer. Simulation results by using both HFSS and CST are presented for comparison. In addition, experimental verifications are presented.
Author(s): K. M. Ibrahim, W. M. Hassan, E. A. Abdallah, A. M. Attiya
File Type: Journal Paper
Issue:Volume: 35      Number: 12      Year: 2020
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Title: Wideband Multi-Port Network Integrated by 3-dB Branch-Line Couplers
Abstract: The design of a multi-port network integrated by symmetrical alignment of four 3-dB branch-line couplers (BLCs) for wideband communication applications is presented. The BLC is designed with the implementation of stub impedance at each port’s transmission line and defect ground structure (DGS) underneath the shunt branches of BLC to improve bandwidth. The designs of the BLC and the multi-port network are performed by using CST Microwave Studio, a three-dimensional (3D) electromagnetic wave simulator. The designed wideband BLC and multi-port are fabricated, and their wideband performances of 2.3 to 5.3 GHz are verified.
Author(s): N. A. M. Shukor, N. Seman, T. A. Rahman
File Type: Journal Paper
Issue:Volume: 33      Number: 7      Year: 2018
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Title: Wideband MIMO Directional Antenna Array with a Simple Meta-material Decoupling Structure for X-Band Applications
Abstract: In this paper, a compact wideband MIMO directional antenna array with a single-layered meta-material is proposed to realize high isolation. The meta-material decoupling structure, which is composed of a modified split-rings and a square loop structure, is suspended over the two antenna elements to reduce the mutual coupling. The achieved results show that the proposed antenna array owns a −10 dB impedance bandwidth ranging from 8.5 GHz to 11.5 GHz. Furthermore, by loading the proposed meta-material superstrate over the two-element MIMO antenna, the designed MIMO antenna array not only has good performance but also enhances the isolation to be more -15 dB within the operating frequency band. In addition, the performances of the proposed antenna array are also tested by radiation pattern, gain, envelope correlation coefficient, diversity gain, total active reflection coefficient and so on. Therefore, these simulation results prove that the proposed wideband MIMO directional antenna array is a suitable candidate for X-band communication.
Author(s): J. Jiang, Y. Li, L. Zhao, X. Liu
File Type: Journal Paper
Issue:Volume: 35      Number: 5      Year: 2020
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Title: Wideband Microstrip Patch Antennas with Transverse Electric Modes
Abstract: A wideband microstrip patch antenna, exciting the fundamental transverse electric (TE) mode, is investigated. The excitation of the TE mode is facilitated through replacing both of the patch and ground plane of a conventional microstrip antenna with artificial magnetic conductors (AMC), consisting of unipolar compact photonic bandgap (UC-PBG) unit cells. The AMC patch and the ground plane of this antenna behave as magnetic conductors within the bandgap region of the unit cells. Similar to conventional patch antennas, it is shown that by cutting a U-shaped slot in the AMC patch, wideband characteristics are realized. The antenna shows a 40% impedance bandwidth and operates at the TE10 mode. Moreover, the width of the patch is 1.75 times smaller than its length, reducing the overall size of the antenna by about 60%, compared with the conventional U-slot PEC antenna supporting the transverse magnetic (TM) mode.
Author(s): T. Mitha, M. Pour
File Type: Journal Paper
Issue:Volume: 35      Number: 8      Year: 2020
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Title: Wideband Microstrip Patch Antennas with Transverse Electric Modes
Abstract: A wideband microstrip patch antenna, exciting the fundamental transverse electric (TE) mode, is investigated. The excitation of the TE mode is facilitated through replacing both of the patch and ground plane of a conventional microstrip antenna with artificial magnetic conductors (AMC), consisting of unipolar compact photonic bandgap (UC-PBG) unit cells. The AMC patch and the ground plane of this antenna behave as magnetic conductors within the bandgap region of the unit cells. Similar to conventional patch antennas, it is shown that by cutting a U-shaped slot in the AMC patch, wideband characteristics are realized. The antenna shows a 40% impedance bandwidth and operates at the TE10 mode. Moreover, the width of the patch is 1.75 times smaller than its length, reducing the overall size of the antenna by about 60%, compared with the conventional U-slot PEC antenna supporting the transverse magnetic (TM) mode.
Author(s): T. Mitha, M. Pour
File Type: Express Journal Paper
Issue:Volume: 35      Number: 8      Year: 2020
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Title: Wideband Microstrip Patch Antenna at 7 GHz
File Type: Conference Paper
Issue:Volume: Student Microwave Design Projects with Sonnet      Number:      Year: 2011
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Title: Wideband Microstrip Endfire Antenna based on SIW and Magnetic Dipole
File Type: Conference Paper
Issue:Volume: 1-P1-C Wideband and Multiband Antennas      Number:      Year: 2017
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Title: Wideband LTCC Vertical-Fed Dipole Antenna for Millimeter-Wave Applications
File Type: Conference Paper
Issue:Volume: 2-2-B Millimeter Wave and Terahertz Antennas      Number:      Year: 2017
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Title: Wideband Low Profile Multi-Polarization Reconfigurable Antenna with Quasi-cross-shaped Coupling Slot
Abstract: A wideband low profile multi-polarization reconfigurable antenna with quasi-cross-shaped coupling slot is proposed. The antenna consists of an upper oval radiating patch, the quasi-cross-shaped coupling slot, fork-shaped folded feed lines and a reconfigurable Wilkinson power divider network with four pairs of p-in diodes. The antenna reconfigurable polarization modes change among ±45° Linear polarization (LP), dual-LP, left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) by controlling the ON/OFF states of the p-i-n diodes. The designed prototype has been fabricated and measured. Good agreement between the measured and simulated results is achieved. Measured results show that the antenna has wide impedance bandwidth (over 21.35% for LP and 17.70% for CP) and axial ratio (AR) bandwidth (16.13% for LHCP and 16.88% for RHCP). The average realized gains are about 7.6 dBi for different polarization modes. The proposed antenna has the advantages of multi-polarization reconfigurable ability, wide bandwidth, low profile, and high gains, which make it possible to be applied to wireless communication systems.
Author(s): Q. Xu, Z. Liu, S. Liu, X. Kong, Z. Huang, B. Bian, Q. Yu, J. Qin
File Type: Journal Paper
Issue:Volume: 35      Number: 3      Year: 2020
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Title: Wideband High-Gain Fabry-Perot Resonator Antenna with Small Footprint Dielectric Superstrates and a Conical Short Horn
File Type: Conference Paper
Issue:Volume: 2-1-B Modeling, Optimization and Design of Antennas      Number:      Year: 2017
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Title: Wideband Hexagonal Fractal Antenna on Epoxy Reinforced Woven Glass Material
Abstract: In this paper a novel hexagonal-circular Fractal antenna is proposed for wideband applications. The proposed antenna is made of iterations of a circular slot inside a hexagonal metallic patch with a transmission line and is fabricated on low cost epoxy matrix reinforced woven glass material. Measurement shows that with a dimension of 0.36?0×0.36?0×0.0071?0 (where ?0 is the lower edge frequency of the operating band), the proposed antenna achieves a wide impedance bandwidth ranging from 1.34 GHz to 3.44 GHz (88%). The proposed antenna also achieves high gain and exhibits a stable radiation pattern which makes it suitable for many wireless communications such as DCS-1800, PCS-1900, IMT-2000/UMTS, ISM (including WLAN), Wi-Fi and Bluetooth.
Author(s): M. A. Dorostkar, R. Azim, M. T. Islam, Z. H. Firouzeh
File Type: Journal Paper
Issue:Volume: 30      Number: 6      Year: 2015
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Title: Wideband GCPW-Fed Dielectric Resonator Antenna for WLAN Applications
File Type: Conference Paper
Issue:Volume: S19 Broadband Antennas and Applications      Number:      Year: 2018
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Title: Wideband Filtering Crossover Based on Ring Resonator with Sharp Rejection
Abstract: A wideband filtering crossover based on ring resonators with sharp rejection is proposed in this paper. Four transmission zeros near the crossover passband can be adjusted conveniently by the even/odd-mode characteristic impedance of the coupled lines. A high selectivity wideband filtering crossover located at 3.0 GHz is designed and fabricated for verification. Good filtering performance and high selectivity for the crossover are realized and experimentally verified.
Author(s): W. Yang, W. Feng, W. Che
File Type: Journal Paper
Issue:Volume: 32      Number: 10      Year: 2017
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Title: Wideband Fabry-Perot Cavity Antenna
File Type: Conference Paper
Issue:Volume: 2-1-B Modeling, Optimization and Design of Antennas      Number:      Year: 2017
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Title: Wideband Equivalent Circuit Model and Parameter Computation of Automotive Ignition Coil Based on Finite Element Analysis
Abstract: This paper presents a coupled fieldcircuit method to predict the wideband characteristic of ignition coils. A lumped circuit model is proposed, which separates the winding of ignition coil into individual sections. In this circuit model, the capacitance between sections, turn-toturn series capacitance of each single section and inductance of winding are calculated by Finite Element Analysis (FEA). This parameter identification is based on the energy principle. In addition, this paper analyzes the influence of frequency on the magnetic-flux distribution and the inductance, using the finite-element model with T- ? formulation. The parameter inductance applied to the circuit model is classified into high frequency inductance and low frequency inductance. Through contrasting the measured and calculated result in frequency and time domain, reliability and feasibility of the presented method in this paper is verified.
Author(s): J. Jin, W. Quan-di, Y. Ji-hui, Z. Ya-li
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
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Title: Wideband Dual-polarized Vivaldi Antenna with Gain Enhancement
Abstract: A wideband dual-polarized Vivaldi antenna covering 1.85-18.3 GHz band with enhanced gain is presented in this letter. The proposed antenna consists of two Vivaldi antenna elements (VAEs), which are designed based on the conventional Vivaldi antenna. Dual-slot structure is employed to improve the gain of the conventional Vivaldi antenna. As a result, sphericallike waves across the slot aperture of the conventional Vivaldi antenna can be transformed to be plane-like waves and thus gain enhancement can be achieved. In order to extend lower frequency limit of the VAE, elliptical slots are adopted. The proposed dual-polarized Vivaldi antenna is obtained by combining two VAEs in a cross-shaped form. The prototype is simulated, fabricated, and measured. A good agreement between EM simulated and measured results evidently validates the proposed antenna.
Author(s): H. Lv, Q. Huang, J. Hou, J. Liu
File Type: Journal Paper
Issue:Volume: 33      Number: 9      Year: 2018
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Title: Wideband Dielectric Resonator Antenna with Parasitic Strip
File Type: Conference Paper
Issue:Volume: Dielectric Resonator Antennas      Number:      Year: 2005
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Title: Wideband Dielectric Resonator Antenna Excited by a Closed Circular Loop GCPW Slot for WLAN 5.5 GHz Applications
Abstract: A dielectric resonator antenna is designed for WLAN 5.5 GHz band applications in this study. The dielectric resonator antenna is fabricated on a cheap FR4 substrate with grounded CPW (GCPW) structure. A new closed circular loop GCPW slot structure is employed to obtain wideband impedance matching. Results of the designed dielectric resonator antenna show that good agreement between simulated and measured reflection coefficients, radiations, and antenna gains is observed. The measured -10 dB bandwidth of the dielectric resonator antenna is 1.6 GHz (28.5%, 4.8 – 6.4 GHz), which covers the WLAN 5.5 GHz band.
Author(s): W.-C. Weng, M.-C. Chang, M.-S. Chen
File Type: Journal Paper
Issue:Volume: 34      Number: 2      Year: 2019
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Title: Wideband Compact Antenna with Partially Radiating Coplanar Ground Plane
Abstract: Many of today's portable communication applications require antennas that are compact, broadband, and easily integrable in a big variety of terminal geometries. This paper presents a compact wideband antenna with partially radiating coplanar ground plane. The prototype of the antenna shows a wide bandwidth (VSWR ? 2) of 92% (from 3.53GHz to 9.5GHz). The antenna also exhibits maximum gain of 3.5dBi and stable radiation patterns over the whole bandwidth. Nevertheless, in this paper the significance of the ground planes on the operating bandwidth are examined with the help of current distribution and discussed in detail with supporting parametric analysis.
Author(s): A. T. Mobashsher, M. T. Islam, N. Misran
File Type: Journal Paper
Issue:Volume: 26      Number: 1      Year: 2011
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Title: Wideband Bow-Tie Slot Antennas with Tapered Tuning Stubs
File Type: Conference Paper
Issue:Volume: Advanced Computational Techniques for Antenna Design      Number:      Year: 2004
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Title: Wideband and High Gain Shared-Aperture Fabry-Perot Resonator Microstrip Antenna
File Type: Conference Paper
Issue:Volume: 2-P2-E Antennas with Advanced/Artificial Materials and Processes      Number:      Year: 2017
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Title: Wideband and Dual-Band Loaded Monopole Dielectric Resonator Antenna
File Type: Conference Paper
Issue:Volume: Recent Antenna Applications      Number:      Year: 2003
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Title: Wide-Angle Claerbout Scheme for Three-Dimensional Time Domain Parabolic Equation and its CN, ADI, AGE Solutions
Abstract: The wide-angle Claerbout scheme of three-dimensional time domain parabolic equation (Claerbout-TDPE) is derived in this paper, which can provide accurate results at angles within 25° of the paraxial direction. At first, the Crank-Nicolson (CN) type is introduced to discretize the Claerbout-TDPE. In this way, a three-dimensional EM scattering problem can be divided into a series of two-dimensional ones. Moreover, the alternating direction implicit (ADI) type is utilized to the Claerbout-TDPE. In this way, a three-dimensional EM scattering problem can be further reduced to a series of one-dimensional ones. Furthermore, the alternating group explicit (AGE) type is introduced to the Claerbout- TDPE for higher computational efficiency. Comparisons are made among the CN, ADI and AGE types in the numerical results.
Author(s): Z. He, H.-C. Yin, R.-S. Chen
File Type: Journal Paper
Issue:Volume: 33      Number: 3      Year: 2018
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Title: Wide-Angle Absorbing Boundary Conditions for Low and High-Order FDTD Algorithms
Abstract: Wide-angle performance of the perfectlymatched- layer absorbing boundary conditions for the finite-difference time-domain (FDTD) method is investigated for efficient modeling of electrically large structures. The original split-field, uniaxial and convolutional perfectly-matched-layer formulations are all optimized to produce near-flat absorption for incidence angles up to 87 degrees. Optimized wide-angle parameters are derived for both the standard FDTD method and a high-order finite-volumes-based variant. The investigated high-order algorithm in particular is shown to produce improved wide-angle performance over standard FDTD for all three perfectly-matched-layer variants even when they are optimized for normal wave incidence. In all cases, optimization is managed through appropriate choices of modeling parameters which can be directly and unobtrusively applied to existing FDTD codes.
Author(s): Mohammed F. Hadi
File Type: Journal Paper
Issue:Volume: 24      Number: 1      Year: 2009
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Title: Wide Stop-Band Microstrip Lowpass Filter with Sharp Roll-off Using Hairpin Resonators
Abstract: A compact microstrip lowpass filter with wide stop-band and sharp roll-off skirt is presented. The structure consists of a combination of modified Hairpin units. The cut-off frequency is 3.1 GHz. The proposed low-pass filter has a very good performance such as extended stop-band bandwidth from 3.36 GHz to 21.5 GHz with the insertion-loss higher than -20.0 dB, sharp roll-off, low insertion-loss, and high return-loss in the passband. The filter is designed, fabricated, and tested and the measured results are in good agreement with the EM-simulation results.
Author(s): M. Hayati, H. S. Vaziri
File Type: Journal Paper
Issue:Volume: 28      Number: 10      Year: 2013
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Title: Wide Bandwidth Endfire Antenna with Log-Period Directors
Abstract: This paper presents the design and implementation of a novel wide bandwidth endfire antenna with log-periodic directors. The feeding structure of the proposed antenna includes a balun which is formed using a pair of microstrip-to-slotline transitions. The proposed antenna has three resonant frequencies in the operating frequency band. Both simulation and measurement results show that the operating frequency band of the antenna for S11 < -10 dB covers the wide bandwidth (5 GHz – 10 GHz), and the relative bandwidth is 67%. Far field measurements in azimuth plane and elevation plane show that the radiation patterns are stable and end fire within the operating band at frequencies of 5 GHz, 7 GHz, 8 GHz, 10 GHz. The proposed antenna radiates a well-defined endfire beam, with a front-to-back ratio > 18 dB and cross polarization level below -28 dB. The dimension of the proposed antenna is 26 mm × 27 mm. Good return loss and radiation pattern characteristics are obtained and measured results are presented to validate the usefulness of the proposed antenna structure for wide bandwidth endfire applications.
Author(s): Y. Sun, G. Wen, H. Jin, P. Wang, Y. Huang, J. Li
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Wide Band Wide Scanning Angle Phased Array Antenna Design in Ku-band
File Type: Conference Paper
Issue:Volume: 1-P1-C Wideband and Multiband Antennas      Number:      Year: 2017
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Title: Wide Band Implantable Antenna Operating at MedRadio Band for MBAN Devices
File Type: Conference Paper
Issue:Volume: 1-4-D EM, Antennas and Wireless Power for Biomedical Applications      Number:      Year: 2017
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Title: Wide Band Flexible Terahertz Metasurface Wave Plate
File Type: Conference Paper
Issue:Volume: 1-SP-4 Metasurfaces/Metamaterials Theory, Design and Applications I      Number:      Year: 2018
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Title: Wide Band Antenna with Ultra-smooth Spectral Characteristics
File Type: Conference Paper
Issue:Volume: S09 Advances in Electromagnetic Modeling by WIPL-D - I      Number:      Year: 2020
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Title: Wide Band Antenna with Ultra-smooth Spectral Characteristics
Abstract: Understanding the evolution of Universe is, in the forefront of, the modern day observational cosmology. It requires precise and accurate measurement of cosmological signal, orders of magnitude weaker than the bright sky background. Detection of such a signal having distinct spectral signature, needs an antenna with frequency independent characteristics over more than an octave bandwidth. A spherical monopole antenna has been designed to operate in the frequency range 50-200 MHz with a spectral smoothness of about few parts in 104. The structure has been modeled and optimized using WIPL-D, to minimize spectral features arising out of abrupt reflections of surface currents and frequency dependent radiation patterns. A prototype has been built to validate the design. This paper presents the methodology adopted in the overall antenna design, experiences in its prototyping and simulation and the measurement results.
Author(s): A. Raghunathan, B. S. Girish, R. Somashekar, K. S. Srivani, S. Singh, R. Subrahmanyan, N. U. Shankar, M. S. Rao, J. Nambissan T.
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: Why does SBVH outperform KD-tree on parallel platforms?
File Type: Conference Paper
Issue:Volume: S41 Parallel and GPU Computations      Number:      Year: 2016
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Title: Whistler Mode Wave Refractive Index in a Finite Temperature Anisotropic Plasma Medium
Abstract: Whistler mode waves, which exist in a magnetized plasma, are prevalent in the Earth's magnetosphere in the extremely low frequency (ELF) and very low frequency (VLF) bands (100 Hz - 30 kHz). Due to the impact of whistler mode waves on space weather processes, it is important to accurately predict the propagation trajectory of these waves and their properties. Numerical raytracing determines the power flow path of the whistler mode waves in the anisotropic medium of the magnetosphere based on local calculation of the refractive index. In the majority of previous work, magnetospheric raytracing has been implemented assuming a cold background plasma (0 K). However, a more accurate description of the magnetospheric plasma includes a background temperature of about 1 eV (11600 K). We present solutions to the dispersion relation that include the effects of finite electron and ion temperatures on the wave refractive index using a warm plasma formulation. Finite temperature effects of the background plasma are shown to be most significant for highly oblique wave normal angles where the refractive index is bounded to smaller values than in the ideal cold plasma approximation.
Author(s): M. Golkowski, A. Maxworth
File Type: Journal Paper
Issue:Volume: 33      Number: 10      Year: 2018
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Title: Whistler Mode Wave Numerical Raytracing in a Finite Temperature Anisotropic Plasma Medium
File Type: Conference Paper
Issue:Volume: S39 Modeling Electromagnetic Waves in Plasma Environments      Number:      Year: 2018
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Title: Whispering Gallery Mode Laser in an Elliptical Microring
Abstract: Studies on whispering gallery mode (WGM) laser in microrings have been limited to circular geometry. Elliptical microring lasers, despite their potential engineering use, have not been analyzed to guide experiments. This paper introduces a computationally efficient method for determining the WGM laser resonance and the laser field distribution in an elliptical microring. An analytical method is applied to avoid computing high order Mathieu functions. Both WGM resonant frequencies and electromagnetic (EM) field distributions are computed and presented in this paper. Computed results clearly show that the WGM laser field is concentrated on the outer surface of the microring. Results also show that the eccentricity of the ellipse affects the distribution of resonant frequencies and the laser field.
Author(s): R. Baktur, L. W. Pearson, J. M. Ballato
File Type: Journal Paper
Issue:Volume: 25      Number: 2      Year: 2010
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Title: Where Intangibles Collide
File Type: Newsletter Paper
Issue:Volume: 20      Number: 2      Year: 2005
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Title: Where does the radiation come from?
File Type: Conference Paper
Issue:Volume: Poster Session 1      Number:      Year: 2003
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Title: What Do You Mean By a Solution to an Operator Equation?
Abstract: The main thrust of this presentation is to illustrate that for many electromagnetic field problems the quality of the solution is very subjective and not objective at all. Therefore to classify solutions on a subjective criteria which is not scientific will create more problems than it would solve. The underlying feature to all this is what do "we mean" by a solution.
Author(s): T.K. Sarkar, E. Arvas, T.K. Sarkar, E. Arvas
File Type: Journal Paper
Issue:Volume: 4      Number: 3      Year: 1989
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Title: Well-Conditioned CFIE for Scattering from Dielectric Coated Conducting Bodies above a Half-Space
Abstract: In this paper, a well-conditioned coupled combined-field integral equation called the electric and magnetic current combined-field integral equation (JCFIE-JMCFIE) is proposed for the analysis of electromagnetic scattering from coated targets above a lossy half-space. The halfspace multilevel fast multipole algorithm (MLFMA) is used to reduce computational complexity. The inner-outer flexible generalized minimal residual method (FGMRES) was used as the iterative solver to further speed up the convergence rate. Numerical results were presented to demonstrate the accuracy and efficiency of the proposed method.
Author(s): D. Ding, J. Ge, R. Chen
File Type: Journal Paper
Issue:Volume: 25      Number: 11      Year: 2010
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Title: Well-Conditioned 2D Models of Rod Arrays for Accelerating 3D Simulations of Photonic Crystals and Plasmonic Structures
File Type: Conference Paper
Issue:Volume: S06 Advanced Methods for Numerical Electromagnetic Analysis - I      Number:      Year: 2021
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Title: Wearable Textile Fabric Based 3D Metamaterials Absorber in X-Band
Abstract: In this paper, a new wearable (flexible) textile fabric-based 3D metamaterials absorber (MMA) structure is proposed. The proposed MMA was created from three layers; weft-knitted fabric, silicone, and plain weave fabric and then, it was simulated in Computer Simulation Technology (CST). It was obtained maximum absorption power (99.66%) at 9.38 GHz, and the average absorption power of 81-95% was obtained in the frequency range of 8 to 12 GHz depending on the incident angle in the simulation. The effect of the wearable textile structure on absorption was investigated. When compared with other materials, it can be said that the proposed MMA is broadband, incident angle independent, TE and TM polarization-independent, flexible, breathable, wearable, ease of fabrication, practical, low weight, and cost advantage. With this designed the textile fabric-based MMA, it can be obtained both low reflection coefficients and low transmission coefficients at broadband X-band frequencies. This provides a good solution for the cloaking of radar systems.
Author(s): E. Delihasanlar, A. H. Yuzer
File Type: Journal Paper
Issue:Volume: 35      Number: 2      Year: 2020
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Title: Wearable Radar Antenna Array Design on Flexible PCB for Visually Impaired People
File Type: Conference Paper
Issue:Volume: S47 Advanced Antenna Designs for Emerging Wireless Applications      Number:      Year: 2021
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Title: Wearable Graphene Based Curved Patch Antenna for Medical Telemetry Applications
Abstract: In order to explore the expediency of graphene for biotelemetry in Wireless Body Area Network (WBAN), conformal square patch antenna design has been presented in this paper. The operational efficiency of the antenna is attributed to the incredible properties of graphene as patch conductor. The proposed antenna designed for operating in band from 1-4.88 GHz is fed with microstrip line and quarter wave transformer for impedance matching. The antenna however achieves best performance at 2.4 GHz in ISM band with good impedance matching, reasonable dB gain and high radiation efficiency for the wideband of frequencies in GHz range. The proposed wearable conformal graphene based antenna is optimally positioned at distance from body to make it suitable for Ultra Wide Band (UWB) health monitoring systems fulfilling the requirements of wideband operation, high gain and improved radiation efficiency at reduced SAR.
Author(s): R. Bala, R. Singh, A. Marwaha, S. Marwaha
File Type: Journal Paper
Issue:Volume: 31      Number: 5      Year: 2016
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Title: Wearable Antennas for Body-Centric Communications: Design and Characterization Aspects
Abstract: Wearable antennas exhibit numerous challenges in terms of design and optimization due to the specific environment in which they operate. Therefore, the design of such antennas is a non-trivial task, as multiple constraints have to be satisfied. We present an algorithm for design-and-optimization of flexible wearable antennas with high radiation efficiency and low specific absorption rate, that takes into account the dielectric loading of the human body. It provides a list of feasible antenna designs, not just a single solution, and identifies the optimal wearable antenna design. Numerical examples on the design and optimization of a wearable antenna (based on a dipole structure with a reflector) to demonstrate the validity and efficiency of the proposed algorithm are given. The optimal antenna design shows robust on-body performance and provides a suitable balance between small antenna size (antenna surface is 2214 mm2), high radiation efficiency (57.73%), and low value of the maximum 10 g average SAR (0.112 W/kg) on a homogeneous semisolid phantom. Finally, the optimal antenna design is fabricated. The antenna performance is studied under different conditions: on a homogeneous semisolid phantom, on a liquid phantom, on a three-layer semisolid phantom, on a human arm and in the free space. A good agreement between simulated and measured antenna performance is observed.
Author(s): A. G. Al-Sehemi, A. A. Al-Ghamdi, N. T. Dishovsky, N. T. Atanasov, G. L. Atanasova
File Type: Journal Paper
Issue:Volume: 34      Number: 8      Year: 2019
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Title: Wearable and implantable RFIDs for Human-body Sensing
File Type: Conference Paper
Issue:Volume: RFIday 2010      Number:      Year: 2010
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Title: Ways to Improve Computational Efficiency of GRE
File Type: Conference Paper
Issue:Volume: High Frequency Techniques      Number:      Year: 2012
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Title: Waveport Modeling for DGTD Method and Its Applications
File Type: Conference Paper
Issue:Volume: 2-SE-3 Advances in Electromagnetic Theory and Simulation Techniques II      Number:      Year: 2018
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Title: Wavelet Packet Transform with Iterative Technique based on Method of Moments
File Type: Conference Paper
Issue:Volume: MoM and Applications      Number:      Year: 2007
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Title: Wavelet Packet Transform of the Method of Moments Matrix for Large-Scale Problems
File Type: Conference Paper
Issue:Volume: MoM and Applications      Number:      Year: 2007
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Title: Wavelet Model of Multivariate Prior Covariance
File Type: Conference Paper
Issue:Volume: S59 Uncertainty Quantification and Modeling for Complex Applications      Number:      Year: 2018
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Title: Wavelet Analysis of Permanent Magnet Synchronous Machine Flux Density Harmonic Content With Different Pole Number Designs
File Type: Conference Paper
Issue:Volume: Advances in CEM      Number:      Year: 2004
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Title: Waveguides with Hyperbolic Metasurface Claddings
File Type: Conference Paper
Issue:Volume: Student Paper Competition      Number:      Year: 2014
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Title: Waveguides with Hyperbolic Metasurface Claddings
File Type: Conference Paper
Issue:Volume: Computational Methods in Nanoelectromagnetics      Number:      Year: 2014
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Title: Waveguides with Exceptional Points of Degeneracy of Order 2, 3, 4 and 6 without Loss and Gain
File Type: Conference Paper
Issue:Volume: S33 Complex Meta-Structures and Applications - II      Number:      Year: 2021
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Title: Waveguide Mode Computation through Smoothed Particle Electromagnetics
File Type: Conference Paper
Issue:Volume: Modeling, Design and Optimization of Complex Electromagnetic Systems      Number:      Year: 2008
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Title: Waveguide Microwave Imaging: Solids Volume Fraction of Particulate Materials
Abstract: An original modeling-based microwave imaging technique for determining the volume fraction of solid material in dielectric powders is described. The desired characteristic is determined by analyzing S-parameter measurements in a waveguide containing the sample with the help of an artificial neural network trained by data from 3D FDTD simulation. The powder sample is represented by a mixture of air and millimeter-scale particles reproduced in the FDTD model. Computational tests with 20 to 40 mm cubic samples of SiC and ZrO2 powders in WR340 show that the solids volume fraction is determined with less than 5% error.
Author(s): A. V. Brovko, E. K. Murphy, V. V. Yakovlev
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Waveguide Filter Modeling and Simulation using Mode-matching, Fullwave Network Analysis and Swarm Optimization
Abstract: This paper presents the modeling of waveguide bandpass filter synthesis. It consists of a combination of the most appropriate and reliable methods and techniques of analysis, simulation and optimization used in determined order and leading to a fast and accurate method of filter synthesis. An example of a forth-order filter synthesis is given, employing a symmetric configuration and symmetric response. The obtained results, reference measurement and commercial software simulator results are compared for validation.
Author(s): I. Bouchachi, J. Mateu, M. L. Riabi
File Type: Journal Paper
Issue:Volume: 32      Number: 2      Year: 2017
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Title: Wavefront Reconstruction Using a Dispersive Propagation Model
File Type: Conference Paper
Issue:Volume: Inverse Scattering in Medicine and Biology - State of the Art, Recent Advances and Future Trends      Number:      Year: 2008
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Title: Waveform of Class E Power Amplifiers with PI Network
File Type: Conference Paper
Issue:Volume: 4-1-C Passive/Active Microwave and Terahertz Devices      Number:      Year: 2017
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Title: Wave Propagation on Two Dimensional Doubly-Periodic Guiding Structures.
File Type: Conference Paper
Issue:Volume: Computer Simulation of Electromagnetic-System Testing      Number:      Year: 2007
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Title: Wave Propagation on a Circular Chiral Rod
File Type: Conference Paper
Issue:Volume: Guided Waves in Non-Standard Media      Number:      Year: 2008
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Title: Wave Propagation and Radio Network Planning Software WinProp added to the Electromagnetic Solver Package FEKO
File Type: Conference Paper
Issue:Volume: S19 Modeling with FEKO      Number:      Year: 2017
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Title: Wave Propagation Along a Thin Vertical Wire Antenna Placed in a Horizontally Layered Medium
File Type: Conference Paper
Issue:Volume: Fundamental Electromagnetics: Materials and Boundaries      Number:      Year: 2010
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Title: Wave Concept Iterative Process Merges with Modal Fast Fourier Transformation to Analyze Microstrip Filters.
Abstract: A novel iterative method based on the concept of waves is reported for use in the field theory, computer aided design and optimization of high frequency integrated circuits. It consists of a recursive relationship between a given source and reflected waves from the discontinuity plane which is divided into cells. A high computational speed has been achieved by using Modal Fast Fourier Transformation (MFFT). The theory as well as its procedure implementation is described. Numerical results are succussfully compared with published data.
Author(s): A. Gharsallah, R. Garcia, A. Gharbi, H. Baudrand, A. Gharsallah, R. Garcia, A. Gharbi, H. Baudrand
File Type: Journal Paper
Issue:Volume: 16      Number: 1      Year: 2001
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Title: Wave Concept in MoM-GEC Formalism
File Type: Conference Paper
Issue:Volume: S34 Computational Electromagnetics Advanced Algorithms and Emerging Applications IV      Number:      Year: 2017
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Title: Wave Characteristics Of Layered Anisotropic Media for Remote Sensing Applications
File Type: Conference Paper
Issue:Volume: S49 EM Modeling and Applications - II      Number:      Year: 2021
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Title: Water-based Metamaterial Absorber for Broadband Electromagnetic Wave Absorption
File Type: Conference Paper
Issue:Volume: 2-1-C Properties, Modelling and Novel Concepts of Artificial Electromagnetic Structures I      Number:      Year: 2017
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Title: Water Extraction of SAR Image Based on Region Merging Algorithm
File Type: Conference Paper
Issue:Volume: 2-1-E Synthetic Aperture Radar Techniques and Applications I      Number:      Year: 2017
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Title: Water Content and Tissue Composition Effects on Microwave Tomography Results
File Type: Conference Paper
Issue:Volume: Microwave Imaging and Inverse Problems      Number:      Year: 2008
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Title: Waffle Iron Filter Design using WIPL-D
File Type: Conference Paper
Issue:Volume: S20 Advances in Electromagnetic Modeling by WIPL-D - II      Number:      Year: 2020
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Title: W-Band Longitudinal-Slot Coupling Four-Way SIW Power Combiner/Divider
File Type: Conference Paper
Issue:Volume: 3-P3-H Passive/Active Microwave and Terahertz Devices      Number:      Year: 2017
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Title: W-band High-Gain Antenna Arrays with Low-Loss Gap Waveguide Feeding Network
File Type: Conference Paper
Issue:Volume: 2-1-B Modeling, Optimization and Design of Antennas      Number:      Year: 2017
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Title: W-band Electronic Focus-Scanning by a Reconfigurable Transmitarray for Millimeter-Wave Imaging Applications
Abstract: A w-band electronic focus-scanning function, which is desired for high-resolution fast-speed millimeterwave imaging systems, is realized by a reconfigurable transmitarray antenna (RTA). As a two-layer structure, each RTA element is integrated with two packaged PIN diodes symmetrically within a limited area (1.6×1.6mm2). When a linearly polarized electromagnetic wave incidents on this reconfigurable element, an orthogonally polarized transmission wave is generated, with the ability of 1-bit phase adjustment (0°/180°). Using this element, a 32×2 reconfigurable transmitarray is designed and fabricated to realize 1-D steerable focal points in a near-distance focal plane. The measured focal points agree well with the design, illustrating the feasibility of the proposed RTA for w-band microwave imaging systems.
Author(s): X. Pan, F. Yang, S. Xu, M. Li
File Type: Journal Paper
Issue:Volume: 35      Number: 5      Year: 2020
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Title: Voxel-Based Inverse Methods
File Type: Conference Paper
Issue:Volume: Nondestructive Evaluation and Materials Characterization      Number:      Year: 2010
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Title: Vortex Beam Optimization Design of Concentric Uniform Circular Array Antenna with Improved Array Factor
Abstract: In this paper, an improved array factor of the concentric uniform circular array (CUCA) antenna is proposed for the orbital angular momentum (OAM) vortex beam optimization design. From the perspective of the radiation pattern’s power conservation principle, a correction factor is introduced to the conventional array factor of CUCA. Then, based on the improved array factor, by adjusting the rings’ radii parameters of the CUCA, we optimize the vortex beam’s sidelobe level through the generic algorithm (GA). Two different CUCA antenna model are calculated as examples to further illustrate the effectiveness of the improved array factor. Subsequently, an electromagnetic simulation model of two rings CUCA antenna is built at C band for generating low sidelobe vortex beam carrying OAM mode. The electromagnetic simulation model of the designed CUCA antenna is also fabricated and measured. The corresponding antenna far-field vortex beam radiation pattern and near-field vortex wave electric field distributions are measured. The simulation results and the measurement results are in good agreement. The proposed designs of antenna and OAM vortex beam regulation are expected to be used for 5G and 6G communications applications.
Author(s): Q. Feng, Y. Lin, Y. Zheng, L. Li
File Type: Journal Paper
Issue:Volume: 36      Number: 7      Year: 2021
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Title: VOLUME LOADING -- A NEW PRICIPLE FOR SMALL ANTENNAS
Abstract: Volume loading means placing conductively enclosed volumes at the ends of the arms of a short linear antenna to increase and control the capacitance of the structure. This technique allows tuning the antenna to make it series-resonant at a design frequency for which it is electrically small. This paper describes the discovery and development of the concept, gives some computed examples to illustrate the relation between shape and performance, and describes some experimental work, including a 900 MHx corless phone demonstration design.
Author(s): D.B. Miron, D.B. Miron
File Type: Journal Paper
Issue:Volume: 14      Number: 2      Year: 1999
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Title: Voltage Parameter Identification of AC Overhead Transmission Lines by Using Measured Electric Field Data
Abstract: With the development of smart power grids, the demand for real-time voltage monitoring along overhead transmission lines (OTLs) has been growing. However, the existing voltage measurement of OTLs by using potential transformers involves formidable difficulties. This study proposes a non-contact measurement method in which the voltages on AC OTLs are inversely calculated on the basis of the measured data of the power frequency electric field under OTLs. To improve the accuracy and stability of the inverse calculation, an accurate mathematical model and modified inverse algorithms are investigated and then a set of feasible approaches are proposed. First, considering an overhead conductor’s actual physical form and the meteorological conditions of its operating environment, a 3-D catenary model is built, and the mathematical relations between 3-D electric fields and the voltages on OTLs are identified. Second, the improved particle swarm algorithm is used to search the optimal measurement positions of the electric field to improve the ill-posedness of inverse problems. Third, the iterative Tikhonov regularization method, in which the number of iterations is considered as the variable, is adopted to further improve the ill-posedness of inverse problems and reduce the susceptibility of regular solutions to regularization parameter alpha. Fourth, root mean square values and phase parameters of AC voltages are identified from the sinusoidal fitting curves obtained by the real-time inverse calculation. Results of the simulation and experiment examples show that inverse solutions of high precision can be obtained under the condition with relatively high errors of electric field measurement. Moreover, the advantages of the proposed inversion method, such as fast computing speed and good stability, are demonstrated.
Author(s): D. Xiao, Q. Zheng, Y. Xie, Q. Ma, Z. Zhang
File Type: Journal Paper
Issue:Volume: 33      Number: 8      Year: 2018
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Title: Voltage and Current Analysis for Arcing Detection on AC Overhead Electrified Railways
File Type: Conference Paper
Issue:Volume: Numerical Techniques for Electromagnetic Applications      Number:      Year: 2011
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Title: Vivaldi Antenna for GPR
File Type: Conference Paper
Issue:Volume: Novel Antennas      Number:      Year: 2009
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Title: Visualizing Time-Domain Distributed Electromagnetic Fields Using Sonnet
File Type: Conference Paper
Issue:Volume: EM Applications in Sonnet      Number:      Year: 2012
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Title: Visualization of Electric Field Amplitudes inside Porous Spherical Cavity Resonators
File Type: Conference Paper
Issue:Volume: EM Applications using WIPL-D      Number:      Year: 2012
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Title: Virtual Source Modeling of the High-Frequency Scattering of the Infinite Conducting Strip under Cylindrical Wave Excitation
File Type: Conference Paper
Issue:Volume: Macromodeling for EMC and SI Complex Systems      Number:      Year: 2007
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Title: Virtual Design of Insulation Elements Based on FEM and Automated Optimization Process
File Type: Conference Paper
Issue:Volume: Hybrid CEM Techniques      Number:      Year: 2005
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Title: Vibration Isolation of Magnetic Suspended Platform with Double Closed-loop PID Control
Abstract: In magnetic vibration isolation field, magnetic force is used for the isolation, while the whole isolation system is always supported passively, which have non-control shortcomings. Aimed at this problem, a novel active control strategy with a double closed-loop PID algorithm was designed in this paper. The double closed-loop strategy includes an internal and external loop control, which was designed to fulfill the magnetic levitation and isolation, respectively. Firstly, the vibration isolation strategy proposed in this paper was simulated in both time and frequency domain. The simulation results showed that this method possesses good performance of vibration isolation. Then, an active levitation and vibration isolation control experiment was designed. The experimental results showed that the control algorithm has a good vibration control effect under periodic vibration and random vibration conditions.
Author(s): M. Tang, J. Zhou, C. Jin, Y. Xu
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Via Modeling in Multi-Gbits/s Signal Analysis
File Type: Conference Paper
Issue:Volume: Black Box Modeling      Number:      Year: 2004
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Title: VHF-UHF Monocone Antenna for Ground Penetrating Radar Application
Abstract: This paper introduces a VHF-UHF monocone antenna for ground penetrating radar GPR application. The proposed antenna covers different bandwidths through only changing the cone geometry. Same ground plane shape and feeding system are used. Firstly, both conventional and proposed monocone antennas are designed, simulated and their simulated results are compared. One antenna cone is fabricated and measured for verification purpose. Good agreement is obtained between measured and simulated bandwidths. The measured bandwidth extends from 73 MHz to 500 MHz. Secondly, another antenna cone is designed and simulated without altering the upper or the lower cone radii. The second cone antenna bandwidth extends from 130 MHz to 1000 MHz. The receiver antenna of the commercial SIR 2000 impulse GPR is replaced by the proposed VHF-UHF first monocone antenna and the field test results are recorded and discussed.
Author(s): T. G. Abouelnaga, E. A. Abdallah
File Type: Journal Paper
Issue:Volume: 34      Number: 5      Year: 2019
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Title: VHF Antennas on Unmanned Air Vehicles (UAV) for a Simplified Synthetic Aperture Radar (SAR)
File Type: Conference Paper
Issue:Volume: Electromagnetic Simulation using FEKO      Number:      Year: 2011
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Title: VHF Antenna Modeling for Rocket Application
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling using FEKO – I      Number:      Year: 2008
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Title: VFD Approach to the Computation TE and TM Modes in Elliptic Waveguide on TM Grid
File Type: Conference Paper
Issue:Volume: Finite Difference Methods      Number:      Year: 2013
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Title: VFD Approach to the Computation TE and TM Modes in Elliptic Waveguide on TM Grid
Abstract: We describe here a vector finite difference approach (VFD) to the evaluation of eigenvalues and modes of elliptical waveguides. The FD is applied using a 2D elliptical grid in the waveguide section. A suitable Taylor expansion of the vector mode function allows to take exactly into account the boundary condition. To prevent the raising of spurious modes, our FD approximation results in a constrained eigenvalue problem, that we solve using a decomposition method. This approach has been evaluated comparing our results to known data for the elliptic case.
Author(s): A. Fanti, G. Montisci, G. Mazzarella, G. A. Casula
File Type: Journal Paper
Issue:Volume: 28      Number: 12      Year: 2013
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Title: Versatile Nanoparticle Manipulation with Designer Thermoplasmonic Metasurface
File Type: Conference Paper
Issue:Volume: S48 Computational Nanophotonics: Advanced Numerical Methods and Applications II      Number:      Year: 2018
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Title: Verifying Received Power Predictions of Wireless InSite Software in Indoor Environments at WLAN Frequencies
Abstract: This paper introduces a study on verifying received power at WLAN frequencies in indoor environments, Wireless InSite is a popular electromagnetic ray-tracing software which is widely used for predicting channel behaviour in indoor and outdoor environments. The study compares software-generated data with measurements collected through 3rd floor Chesham Building, University of Bradford, at WLAN frequencies, the paper also investigates the effect of changing settings on results accuracy and computational time, and finally, the paper presents a comparison between simulation results with empirical models.
Author(s): H. A. Obeidat, O. A. Obeidat, M. F. Mosleh, A. A. Abdullah, R. A. Abd-Alhameed
File Type: Journal Paper
Issue:Volume: 35      Number: 10      Year: 2020
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Title: Verify Microstrip Antenna Using Feature Selective Verification Method
File Type: Conference Paper
Issue:Volume: 4-3-B Antenna Design and Optimization Techniques I      Number:      Year: 2017
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Title: Verification Testing of Multi-Dynamical Solver for Multiferroic Antennas
File Type: Conference Paper
Issue:Volume: S42 Computational Methods      Number:      Year: 2021
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Title: Verification of the CADRCS RCS tool for NCTR work
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling, Inversion and Applications      Number:      Year: 2007
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Title: VERIFICATION OF SOFTWARES FOR ELECTROMAGNETIC FIELD ANALYSIS USING MODELS PROPOSED BY INVESTIGATION COMMITTEES IN IEE OF JAPAN
Abstract: In order to investigate methods for analyzing electromagnetic fields and to compare the accuracy and the CPU time of various codes and so on, investigation committees were set up in IEE of Japan. In this paper, the activities of various investigation committees relating electromagnetic field analysis are described from the viewpoint of the verification of software. [Vol. 12, No. 3 (1997), pp 50-61
Author(s): Norio Takahashi, Norio Takahashi
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
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Title: Verification of Nonlinear Characteristics of Radar Angular Glint by Surrogate Data Method
Abstract: In this paper, we present a nontrivial verification of nonlinear characteristics of angular glint by the surrogate data method. Glint is a key cause of target loss in radar detections. Prediction and suppression of glint is a hot topic. Firstly, glint data of a typical target are calculated by GRECO method for two motions. As glint is calculated by quadric surface calculations, it is nonlinear in mathematical nature. The surrogate data method is explained and workflow is summarized to verify the nonlinear traits of glint. Surrogate methods of phase randomized Fourier transform and amplitude adjusted Fourier transform are illustrated. Test statistics of higher order moments and time reversibility are given. Lorenz model is simulated as a standard nonlinear model to verify effectiveness of workflow, and nonlinear verification criteria are drawn. A new parameter is designed to measure the powerfulness of nonlinearity. Finally, nonlinear verifications for the two angular glint series are given. Results are illustrated in figures and data and they agree with nonlinear criterion. This paper lays the foundations for chaotic verifications of glint.
Author(s): J. Zhang, Z. Li, C. zheng, J. Miao
File Type: Journal Paper
Issue:Volume: 28      Number: 10      Year: 2013
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Title: Vectorial GO and Diffraction Decomposition of Physical Optics Scattering of Dipole Wave from Planar Surfaces in Terms of Modified Edge Representation Line Integrals
File Type: Conference Paper
Issue:Volume: Asymptotic and High Frequency Techniques      Number:      Year: 2005
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Title: Vector Parabolic Equation Modeling of Wireless Propagation in Tunnels with Statistically Rough Surface Walls
File Type: Conference Paper
Issue:Volume: S59 Uncertainty Quantification and Modeling for Complex Applications      Number:      Year: 2018
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Title: Vector Parabolic Equation Modeling of Wireless Propagation in Tunnels with Statistically Rough Surface Walls
File Type: Conference Paper
Issue:Volume: S10 Student Paper Competition II      Number:      Year: 2018
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Title: Vector Parabolic Equation Method for the EM Scattering from PEC Objects in Half-Space
Abstract: The vector parabolic equation method was widely used to analyze the electromagnetic scattering from electrically large PEC objects in free space. In this paper, it is applied for the analysis of the electromagnetic scattering from PEC objects in halfspace. By introducing both the incident field and the reflected field to illuminate the objects, the vector parabolic equation method can be used to efficiently calculate the radar cross-section of PEC objects with electrically large size in half-space. The numerical results demonstrate that the proposed method can efficiently give reasonably accurate results.
Author(s): Z. He, T. Su, R. S. Chen
File Type: Journal Paper
Issue:Volume: 30      Number: 8      Year: 2015
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Title: Vector Control of PMSM Take Over by Photovoltaic Source
Abstract: This article established with the modeling and the field oriented control of permanent magnet synchronous machines, with a focus on their applications in variable speed domain in photovoltaic source.
Author(s): T. Yuvaraja, K. Ramya
File Type: Express Journal Paper
Issue:Volume: 1      Number: 6      Year: 2016
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Title: Vector Control of PMSM Take Over by Photovoltaic Source
Abstract: This article established with the modeling and the field oriented control of permanent magnet synchronous machines, with a focus on their applications in variable speed domain in photovoltaic source.
Author(s): T. Yuvaraja, K. Ramya
File Type: Journal Paper
Issue:Volume: 33      Number: 2      Year: 2018
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Title: Vector Control of PMSM Take Over by Photovoltaic Source
Abstract: This article established with the modeling and the field oriented control of permanent magnet synchronous machines, with a focus on their applications in variable speed domain in photovoltaic source.
Author(s): T. Yuvaraja, K. Ramya
File Type: Express Journal Paper
Issue:Volume: 33      Number: 2      Year: 2018
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Title: VARIOUS APPROACHES TO TORQUE CALCULATIONS BY FEM AND BEM
Abstract: Different algorithms for the torque calculation by Maxwell stress method (MSM) are dealt with in the paper. The aim of designing these algorithms was to reduce the influence of the choice of the integration path and discretization of the air gap between the stator and rotor on the accuracy of the results. In some of these algorithms the connection between the stator and rotor is released For the magnetic field calculation the finite element method (FEM), boundary element method (BEM), and hybrid finite element - boundary element method (HM) were used. The calculation results were tested on a permanent magnet DC motor and a single phase brushless motor. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 127-130]
Author(s): Mladen Trlep, Anton Hamler, Bozidar Hribernik, Mladen Trlep, Anton Hamler, Bozidar Hribernik
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: Variational Analysis of Substrate-Integrated Waveguides with Longitudinal Slot
File Type: Conference Paper
Issue:Volume: S43 Advanced Applications I      Number:      Year: 2017
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Title: Variable Phase-Shifter/Down Converter for Active Microstrip Phased Array Antenna Applications
File Type: Conference Paper
Issue:Volume: Poster Sessions 1      Number:      Year: 2007
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Title: Validity of Approximate Boundary Conditions in Analysis of Strip-Loaded Planar and Curved Surfaces
File Type: Conference Paper
Issue:Volume: Poster Sessions 1      Number:      Year: 2007
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Title: Validation, Verification and Calibration in Applied Computational Electromagnetics
Abstract: Model validation, data verification, and code calibration (VV&C) in applied computational electromagnetics is discussed. The step by step VV&C procedure is given systematically through canonical scenarios and examples. Propagation over flat-Earth with linearly decreasing vertical refractivity profile, having an analytical exact solution, is taken into account as the real-life problem. The parabolic wave equation (PWE) is considered as the mathematical model. MatLab-based numerical simulators for both the split step Fourier and finite element implementations of the PWE are developed. The simulators are calibrated against analytical exact and high frequency asymptotic solutions. Problems related to the generation of reference data during accurate numerical computations are presented.
Author(s): G. Apaydin, L. Sevgi
File Type: Journal Paper
Issue:Volume: 25      Number: 12      Year: 2010
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Title: Validation, Verification and Calibration in Applied Computational Electromagnetics
File Type: Conference Paper
Issue:Volume: CEM for EM Education      Number:      Year: 2010
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Title: VALIDATION OF, AND LIMITATIONS ON, THE USE OF NEC-4 FOR RADIATION FROM ANTENNAS BURIED WITHIN A HOMOGENEOUS HALF-SPACE
Abstract: The use of the computer program NEC-4 for the simulation of radiation from buried antennas is considered. NEC-4 uses the “exact” Sommerfield integral formulation for stratified media (in NEC-4, re-stricted to an homogeneous half-space). Although the formulation is rigorous, certain approximations have to be made for numerical implementation. The formu-lation, and some of these issues, is outlined in the paper. Several validation examples comparing results computed using NEC-4 and results available in the lit-erature are presented for antennas buried in various typical media, including ground, fresh water, and the sea. Satisfactory agreement has generally been obtained; where differences have been noted, we have able to explain most in terms of approximate implementa-tion issues.
Author(s): David B. Davidson, H. du Toit Mouton, David B. Davidson, H. du Toit Mouton
File Type: Journal Paper
Issue:Volume: 13      Number: 3      Year: 1998
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Title: Validation of Wind Turbine Doppler Signatures in a Passive Bistatic Radar with a Point Scatterer Model
File Type: Conference Paper
Issue:Volume: S06 Advanced Radar Technologies and Techniques I      Number:      Year: 2019
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Title: VALIDATION OF THE NUMERICAL ELECTROMAGNETICS CODE (NEC) FOR ANTENNA WIRE ELEMENTS IN PROXIMITY TO EARTH
Abstract: This paper summarizes recent MITRE efforts to validate the NEC-3 and NEC-GS versions of the Numerical Electromagnetics Code (NEC) developed by Lawrence Livermore National Laboratory for predicting the performance of antenna wire elements in close proximity to flat earth. In an early version (NEC-l), the effect of the air-ground interface was included by applying a plane-wave Fresnel rei:lection coefficient approximation to the field of a point source. The NEC-2 version, while still retaining the Fresnel reflection coefficient model as an option, provides a more accurate ground model by numerically evaluating Sommerfeld integrals. The version NEC-3 extends the NEC-2 version to cases for bare wire segments below the air-earth interface. Version NEC-GS utilizes rotational symmetry to provide a more efficient version of NEC-3 for the case of a monopole element with a uniform radial wire ground-screen (GS). Results of the various versions are compared with each other and with other mndels. The input-output format of the NEC-GS version is discussed. It is concluded that the NEC-3 Sommerfeld integral option in the NEC-GS version is the best available model for monopole elements with electrically small radial-wire ground planes. [Vol. 8, No. 2 (1993), pp 44-71]
Author(s): M. M. Weiner, M. M. Weiner
File Type: Journal Paper
Issue:Volume: 8      Number: 2      Year: 1993
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Title: VALIDATION OF THE MININEC3 CODE FOR COMPLEX RADIATING STRUCTURES
Abstract: The ability of the MININEC3 code to accurately model complex radiating structures was previously unknown because computer compiler constraints limited the size of analyzable configuration. With the conversion of the code from BASIC to FORTRAN however it is now feasible to use it to simulate such structures. This paper presents the results of a validation exercise aimed at assessing the code's suitability for modelling configurations which involve hundreds of segments. [Vol. 9, No. 1 (1994), pp 58-66]
Author(s): K.P. Murray, B.A. Austin, K.P. Murray, B.A. Austin
File Type: Journal Paper
Issue:Volume: 9      Number: 1      Year: 1994
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Title: Validation of Fast Site-Specific Mean-Value Models for Indoor Propagation
Abstract: A fast assessment of the local mean value of the electric field strength throughout a floor plan is useful for the design of local-area networks. Site-specific models require coding the location of walls, doorways, and other features and modelling their structure and electrical properties. Using ray tracing to find the field strength throughout the floor plan is slow and expensive because a grid of closely-spaced points is needed to trace the rapid variations called fast fading; then the raytracing local area average is found by explicit spatial averaging, to obtain the slow fading behavior. The raytracing mean value is obtained by combining the amplitudes of the fields associated with the rays on an energy basis; widely-spaced grid points can be used because the local mean value varies slowly with position, making the calculation fast and inexpensive. The Sabine method provides a energy-balance approach for an inexpensive estimate of the local mean value field strength. This paper tests the accuracy of the fast methods (the ray-tracing mean value and the Sabine mean value) against the local area average found from dense ray tracing, and against measurements. In a 40 m2 room of roughly square floor plan, the fields from the fast methods were close to those of dense ray tracing and to the measurements. But it is shown that in a long corridor, the ray-tracing mean value and the Sabine mean value were low compared to dense ray tracing, and so these fast methods should be used with caution.
Author(s): C. W. Trueman, D. Davis, B. Segal, W. Muneer
File Type: Journal Paper
Issue:Volume: 24      Number: 3      Year: 2009
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Title: Validation of a Z-Matrix Finite Element Program for Analyzing Electrostatic Fields
Abstract: Modern electrical equipment designs demand more compact, complex geometries and require more strigent analyses of the associated three-dimensional electrostatic fields. Analytical solutions of such fields are limited to relatively simple geometries. Numerical solutions using the finite element method are limited by available computer storage and processing time. Lauber posed an economical method for solving three-dimensional finite element electrostatic fields by forming the finite element system matrix using Brown's Z-matrix techniques. (Lauber, 1982) (Brown, 1975) This method was implemented by a FORTRAN computer program. (Barber and Lauber, 1986) (Barber, 1988) The purpose of this paper is to briefly describe the present version of the program called FEWZ (Finite Elements using a Windown and the Z-matrix) and to show how it was validated.
Author(s): P.F. Barber, T.S. Lauber, E.D. Patterson, P.F. Barber, T.S. Lauber, E.D. Patterson
File Type: Journal Paper
Issue:Volume: 4      Number: 3      Year: 1989
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Title: VALIDATION AND DEMONSTRATION OF FREQUENCY APPROXIMATION METHODS FOR MODELING DISPERSIVE MEDIA IN FDTD
Abstract: Recently, digital signal processing techniques were used to design, analyze and implement discrete models of polarization dispersion for the Finite-Difference Time-Domain (FDTD) method. The goals of the present work are to illustrate the FDTD update equations for these techniques and to validate and demonstrate these techniques for one-dimensional problems involving reflections from dispersive dielectric half-spaces. Numerical results are compared with several other dispersive medial FDTD implementations.
Author(s): J.H. Beggs, J.H. Beggs
File Type: Journal Paper
Issue:Volume: 14      Number: 2      Year: 1999
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Title: Validating the Magnetostatic Frill Source with WIPL-D
File Type: Conference Paper
Issue:Volume: Electromagnetic Simulation using Wipl-D      Number:      Year: 2011
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Title: Validating Numerical Models – Quantifying Error
Abstract:
Author(s):
File Type: Newsletter Paper
Issue:Volume: 19      Number: 1      Year: 2004
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Title: Valence Electron High-harmonic Generation Analysis by the Finite Difference Time Domain Method
File Type: Conference Paper
Issue:Volume: 2-2-A Multiphysics Modeling and Simulation      Number:      Year: 2017
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Title: V-Band Frequency Reconfigurable Cavity-Based Bandpass Filters
File Type: Conference Paper
Issue:Volume: S55 Nanotechnology      Number:      Year: 2016
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Title: V Transmission lines Frequency Operation Band
File Type: Conference Paper
Issue:Volume: Microwave, Optical Devices, and Propagation      Number:      Year: 2007
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Title: UWB-MIMO Quadruple with FSS-Inspired Decoupling Structures and Defected Grounds
Abstract: In this paper, a quad element Ultra Wideband Multiple-Input Multiple-Output (UWB-MIMO) antenna system is presented. The proposed design is compact as it has four semielliptical shaped antennas along with the decoupling structures, fabricated on a compact substrate. The substrate employed is a low cost FR-4 laminate. The antenna elements are decoupled by employing Defected Ground Structures (DGS) and structures inspired from Frequency Selective Surfaces. An enhanced impedance match over lower to medium band is achieved by introducing dipole-like parasitic stubs on rear sides of the antennas. Measured results show that the isolation achieved by the proposed design is more than 20 dB over desired frequency band.
Author(s): T. Shabbir, R. Saleem, A. Akram, F. Shafique
File Type: Journal Paper
Issue:Volume: 30      Number: 2      Year: 2015
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Title: UWB Square Monopole Antenna with Omni-Directional Radiation Patterns for Use in Circular Cylindrical Microwave Imaging Systems
Abstract: In this paper, a novel ultra-wideband printed monopole antenna (PMA) for the use in a circular cylindrical microwave imaging system is presented. The proposed antenna consists of a square radiating patch and a ground plane with a pair of L-shaped slots and two L-shaped conductor back plane, which provides a wide usable fractional bandwidth of more than 130 % (3.02 GHz - 15.21 GHz). By cutting two modified Lshaped slots with variable dimensions on the ground plane corners and also by inserting two Lshaped conductor back plane on the other side of the substrate, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The proposed antenna has an ordinary square radiating patch, therefore displays a good omni-directional radiation pattern even at higher frequencies, and also its radiation efficiency is greater than 82% across the entire radiating band. The designed antenna has a small size of 12 × 18 mm2. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for circular cylindrical microwave imaging system.
Author(s): N. Ojaroudi, M. Ojaroudi, N. Ghadimi, M. Mehranpour
File Type: Journal Paper
Issue:Volume: 28      Number: 2      Year: 2013
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Title: UWB Slot Antenna with Band-Stop Operation by Using H-Shaped Parasitic Structures for UWB Applications
Abstract: A novel ultra wideband (UWB) printed slot antenna with band-notched performance is designed and manufactured. In order to increase the impedance bandwidth of the slot antenna, we use a rectangular slot with an H-shaped parasitic structure inside the rectangular slot on the feedline that with this structure UWB frequency range can be achieved. Additionally, by using a square ring radiating stub with a rotated H-shaped parasitic structure inside the square ring, a frequency band-stop performance has been obtained. The designed antenna has a small size of 20 × 20 mm2 while showing the radiation performance in the frequency band of 2.97 GHz to over 12.39 GHz with a band rejection performance in the frequency band of 5.01 GHz to 5.98 GHz. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.
Author(s): M. Ojaroudi, N. Ojaroudi, N. Ghadimi
File Type: Journal Paper
Issue:Volume: 28      Number: 12      Year: 2013
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Title: UWB Slot Antenna with Band-Notched Property with Time Domain Modeling based on Genetic Algorithm Optimization
Abstract: This paper presents a kind of band-notched slot antenna with time domain designing method for ultra-wideband (UWB) applications. The proposed antenna consists of a square radiating stub with a defected mircostrip feed-line using an M-shaped step impedance resonator (SIR) slot and a defected ground plane with a pair of inverted U-shaped slots. By cutting two inverted U-shaped slots in the ground plane, a new resonance at the higher frequencies is excited and hence much wider impedance bandwidth can be produced that. To generate a band-notched characteristic, we use an M-shaped slot at the feed-line. The proposed antenna can operate from 3.03 to 13.21 GHz with frequency band-notched function in 7.28-7.79 GHz to avoid interference from downlink of X-band satellite communication systems. To verify the validation of the proposed antenna an equivalent circuit based on time domain reflectometry (TDR) analysis is presented. In addition, the accuracy of the equivalent circuit models have been improved using Genetic algorithm optimization (GAP). Detailed simulation and numerical investigations are conducted to understand their behaviors and optimize for broadband operation. The proposed antenna exhibits almost omni-directional radiation patterns in UWB frequency range and could be used in wireless systems.
Author(s): J. Zolghadr, Y. Cai, N. Ojaroudi
File Type: Journal Paper
Issue:Volume: 31      Number: 8      Year: 2016
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Title: UWB Sampler for Wireless Communications and Radar
File Type: Conference Paper
Issue:Volume: Technologies for Ultra-Wideband Communication      Number:      Year: 2005
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Title: UWB Monopole Antenna with WLAN Frequency Band-Notched Performance by using a Pair of E-Shaped Slits
Abstract: In this paper an ultra-wideband monopole antenna with frequency band-stop performance is designed and manufactured. The proposed antenna consists of square radiating patch with two E-shaped slits and a ground plane with a protruded T-shaped strip inside the rectangular slot. In the proposed structure, by inserting a rectangular slot with a T-shaped strip protruded inside the slot on the ground plane, additional resonance is excited and hence, much wider impedance bandwidth can be produced, especially at the higher band. In order to create band-rejected function we use two E-shaped slits in the square radiating patch. The fabricated antenna has the frequency band of 3 GHz to over 12.7 GHz with a rejection band around 5 GHz – 6 GHz. Good VSWR and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications
Author(s): N. Ojaroudi, M. Ojaroudi, N. Ghadimi
File Type: Journal Paper
Issue:Volume: 28      Number: 12      Year: 2013
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Title: UWB Monopole Antenna with Switchable Band-Notch Characteristic Using a Novel MEMS Afloat
Abstract: In this paper, a novel microelectro-mechanical system (MEMS) U-shaped afloat is designed and used instead of a simple slot to activate and deactivate the band notch characteristic of an ultra wideband (UWB) monopole antenna at the WLAN band (5.15-5.825 GHz) without extra DC bias lines. The novelty of this work is design of MEMS afloat that can stay in down state permanently. When the dc actuation voltage, about 20 volts, is applied to the microstrip center line, the ?/2 long U-shaped afloat moves down and creates a slot (resonating element) in its vacant place. Whereas no voltage is applied, the afloat remains in the up position and serves as a part of the antenna, which eliminates the resonance. The proposed design for MEMS afloat has least negative effect on gain, reflection coefficient, and pattern of the antenna. The gain of the antenna is about 3.2 dBi over the entire UWB frequency band (3.1-10.6 GHz), while it decreases sharply over 7 dB at the rejection band. More-over, the time-domain characteristics of the antenna is investigated, which shows 1 ns delay over the UWB frequency band for 20 cm. Due to a novel afloat design, the addition of the resonance element does not affect on the radiation performance, reflection coefficient, gain, and group delay of the antenna outside of notched band frequencies.
Author(s): A. Nemati, B. A. Ganji
File Type: Journal Paper
Issue:Volume: 30      Number: 12      Year: 2015
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Title: UWB Monopole Antenna with Dual Band-Stop Performance Using G-Shaped SRR and SIR Structures at Feed Line
Abstract: This article presents a new design of ultra-wideband monopole antenna with the characteristics of dual band rejection .The antenna consists of a circular radiating patch, a feed-line with G-shaped Step-Impedance Resonator (SIR) slot and Split-Ring Resonator (SRR) structure, and a ground plane which provides a wide usable fractional bandwidth of more than 120% with two notch bands around 5.15-5.35 GHz and 7.25-7.75 GHz, to avoid interferences from High Performance Radio Local Area Networks (HIPERLAN) and downlink frequency of X-band satellite systems. The simulated and measured results show that the antenna design exhibits an operating bandwidth (VSWR<2) from 2.86 to 12.92 GHz, excluding the rejected bands. The proposed antenna configuration is simple, easy to fabricate and can be integrated into any UWB system. The antenna has an ordinary circular-disc radiating patch, therefore displays good omnidirectional radiation patterns, even at higher frequencies.
Author(s): S. Ojaroudi, Y. Ojaroudi, N. Ghadimi, N. Ojaroudi
File Type: Journal Paper
Issue:Volume: 29      Number: 10      Year: 2014
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Title: UWB Monopole Antenna with Dual Band-Notched Function
Abstract: In this letter, an Ultra-Wideband (UWB) monopole antenna with dual frequency band-stop performance is designed and manufactured. In the proposed structure, by inserting an S-shaped parasitic structure inside a square slot in the ground plane a new resonance at higher frequencies can be achieved, which provides a wide usable fractional bandwidth of more than 125%. In order to generate dual bandnotched function, we use four L-shaped strips protruded inside square ring. The measured results reveal that the antenna offers a very wide bandwidth from 2.63 to 14.2 GHz with two notched bands covering all the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX and 4 GHz C bands. Good VSWR and radiation pattern characteristics are obtained in the frequency band of interest.
Author(s): Y. Ojaroudi, S. Ojaroudi, N. Ojaroudi
File Type: Journal Paper
Issue:Volume: 30      Number: 2      Year: 2015
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Title: UWB Monopole Antenna with Compact Polygon-Shaped Patch for Portable Devices
Abstract: In this paper, a small ultra wideband (UWB) antenna with co-planar waveguide (CPW) feed, consisting of a polygon-shaped design on the patch and a ground plane truncated with two mirror rectangular–shaped notches is designed for ultra wideband (UWB) applications. In this proposed antenna, through increasing the number of cuts inside the initial patch, a proper control on the upper frequency of the band can be achieved. The overall dimension of the antenna is 19×19 ×1 mm3 and fed by 50 ? coplanar waveguide. The proposed antenna is developed and its VSWR is compared with the simulated result. The proposed antenna operates in the adopted bandwidth (3.1 GHz-10.6 GHz) with VSWR < 2, and covers it very well from 3 GHz to 14.9 GHz, which provides fractional bandwidths of more than 132%. The effect of the ground plane notch on the optimization of the VSWR is discussed in detail.
Author(s): T. Sedghi, V. Rafii, M. Moosazadeh
File Type: Journal Paper
Issue:Volume: 29      Number: 1      Year: 2014
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Title: UWB MIMO Antenna with Decoupling Strip for 5G Applications
File Type: Conference Paper
Issue:Volume: S47 Advanced Antenna Designs for Emerging Wireless Applications      Number:      Year: 2021
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Title: UWB MIMO Antenna for High Speed Wireless Applications
Abstract: The paper proposes a MIMO antenna composed of two elements in the form of UWB monopole antennas. Polarization diversity of the proposed antenna is obtained locating the two elements perpendicularly on a common substrate. Also the isolation between elements is accomplished without using any extra decoupling structures. The two monopoles antennas with half elliptical shape are fed with asymmetric coplanar strip (ACS). The presented antenna is located on substrate 48 × 28 mm2 in total size. The distance between the two elements is 15 mm that is 0.15λ0 at 3GHz. The antenna was designed to work effectively from 3 to 11.5 GHz with reflection coefficient better than -10 dB and isolation lower than 18 dB. In addition, antenna with elements located in parallel was designed to show the advantage of the original design. Envelope correlation coefficient, diversity gain and channel capacity loss document the antennas behavior. The antenna was fabricated and measured. Measurement validated the simulation and showed that the designed antenna can be well applied in UWB MIMO systems.
Author(s): A. A. Ibrahim, J. Machac, R. M. Shubair
File Type: Journal Paper
Issue:Volume: 34      Number: 9      Year: 2019
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Title: UWB Microstrip-Fed Slot Antenna with Band-Rejection Performance Using an SRR Conductor-Backed Plane
Abstract: In this article, a novel and compact ultra-wideband (UWB) slot antenna with bandnotched function is presented. This antenna consist of a square radiating stub, a 50? microstrip feedline, a ground plane with a pair of rotated Tshaped strips protruded inside square slots and a Split Ring Resonator (SRR) conductor-backed plane. In this design, by cutting a pair of modified square slots with rotated T-shaped strips protruded inside slots, additional resonance is excited and hence much wider impedance bandwidth can be produced. In order to achieve a band-notched function, an SRR parasitic structure was inserted in the ground plane. The measured results show that the proposed antenna can achieve the Voltage Standing Wave Ratio (VSWR) requirement of less than 2.0 in frequency range from 3.1 GHz to 13.15 GHz, with band-rejection performance of 5.08 GHz to 6 GHz, to avoid interference from WLAN communications. The presented microstrip-fed slot antenna exhibits good radiation behavior. The antenna has a small size.
Author(s): N. Ojaroudi, N. Ghadimi, Y. Ojaroudi
File Type: Journal Paper
Issue:Volume: 29      Number: 3      Year: 2014
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Title: UWB Gain Enhancement of Horn Antennas Using Miniaturized Frequency Selective Surface
Abstract: In this work, enhancement of the radiation performances of horn antennas are worked out within their operation bandwidth by placing the miniaturized Frequency Selective Surface (FSS)s perpendicularly into the inner part of their flares. Here each FSS consists of only a single miniaturized double-sided inverted Tshaped square unit cell designed on the low-cost FR4 with relative permittivity 4.4, loss tangent 0.0035 and thickness 1.58 mm in 3D CST environment so that it is able to focus the propagating electromagnetic waves to increase the directivity properties like a dielectric lens, while keeping the mismatching characteristics with less size and low manufacturing cost compared to its counter parts. Herein an exponentially tapered TEM horn with the operation bandwidth of 5-13 GHz is taken as an example horn antenna for measurements. From the measured results of the prototyped module, it can be observed that the proposed module keep mismatching characteristics of the horn antenna, meanwhile the gain and beam widths are enhanced to amplify the signal in the operation band without any increase in the total volume of the module or making the design bulky. Thus, it is expected that this methodology can be implemented to horn antennas effectively reducing volume and cost of communication systems.
Author(s): M. A. Belen, F. Gunes, P. Mahouti, A. Belen
File Type: Journal Paper
Issue:Volume: 33      Number: 9      Year: 2018
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Title: UWB Compact TEM Ridged Horn Antenna
File Type: Conference Paper
Issue:Volume: Application of Electromagnetic Simulation for Designing and Analysis of Antennas and Radio Propagations Part I      Number:      Year: 2014
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Title: Utilizing Particle Swarm Optimization in the Field Computation of Non-Linear Magnetic Media
Abstract: It is well known that the computation of magnetic fields in nonlinear magnetic media my be carried out using various techniques. In the case of problems involving complex geometries or magnetic media, numerical approaches become especially more appealing. The purpose of the paper is to present an automated particle swarm optimization approach using which field computations may be carried out
Author(s): A. A. Adly, S. K. Abd-El-Hafiz, A. A. Adly, S. K. Abd-El-Hafiz
File Type: Journal Paper
Issue:Volume: 18      Number: 3      Year: 2003
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Title: Utilizing Hybrid Dielectric-Metal and Mesh Refinement Techniques When Modeling a MMIC in Concerto Quickwave
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling with QuickWave/Concerto      Number:      Year: 2008
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Title: Utilization of Protruded Strip Resonators to Design a Compact UWB Antenna with WiMAX and WLAN Notch Bands
Abstract: In this paper, a new design of ultrawideband (UWB) microstrip monopole antenna is presented. The main novelty of the proposed structure is the using of protruded strips as resonators to design an UWB antenna with dual band-stop property. In the proposed design, by cutting the rectangular slot with a pair of rotated Y-shaped strips in the ground plane, additional resonance is excited and much wider impedance bandwidth can be achieved. To make a single band-notched function, the square radiating patch is converted to the square-ring structure with a pair of protruded fork-shaped strips. Finally, by cutting a rectangular slot with a protruded M-shaped strip at the feed line, a desired dual band-notched function is achieved. The measured results reveal that the presented dual band-notched antenna offers a very wide bandwidth from 2.8 to 11.6 GHz, with two notched bands, around of 3.3-3.7 GHz and 5-6 GHz covering all WiMAX and WLAN bands.
Author(s): J. Mazloum, N. Ojaroudi
File Type: Journal Paper
Issue:Volume: 31      Number: 2      Year: 2016
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Title: UTD Shooting-and-Bouncing Extension to a PO/PTD Ray Tracing Algorithm
Abstract: This paper deals with the efficient combination of three well-established electromagnetic modeling methods, a Shooting-and-Bouncing-Rays (SBR) algorithm on the basis of the Geometrical Optics (GO), a source-based calculation of scattered field strengths using Physical Optics (PO) and Physical Theory of Diffraction (PTD), and diffraction calculation on the basis of the Uniform Theory of Diffraction (UTD). While the conventional GO-PO/PTD methods are able to accurately calculate wedge contributions to scattered fields, the further propagation of diffracted rays is generally not considered in SBR approaches. Thus, the aim of this paper is to describe the implementation of diffracted rays according to the UTD concept into an SBR code. This novel implementation allows for the modeling of double diffraction and reflected-diffractedreflected paths in complex scenarios consisting of a very large number of surface elements as well as the accurate simulation of cavities. The comparison with numerically exact reference simulations proves that the proposed hybrid GO/UTD-PO/PTD algorithm yields excellent results and that the UTD-SBR extension definitely improves the simulations of the ray tracing algorithm also for realistic objects.
Author(s): F. Weinmann
File Type: Journal Paper
Issue:Volume: 24      Number: 3      Year: 2009
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Title: UTD Ray and Beam Methods for Analysis of Large EM Wave Problems Abstract
File Type: Tutorial Abstract
Issue:Volume: S35 UTD Ray and Beam Methods for Analysis of Large EM Wave Problems      Number:      Year: 2015
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Title: Using YATPAC for Modeling of a Marchand Balun
File Type: Conference Paper
Issue:Volume: MEFiSTo Modeling and Analysis      Number:      Year: 2007
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Title: Using Transfer Function Approach To Develop MRI Visible and Low RF Heating Sleeve for Cardiac Applicaion
File Type: Conference Paper
Issue:Volume: S54 Computational Electromagnetic Modeling in EMC Applications      Number:      Year: 2016
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Title: Using Time-domain Codes to Find RF Cavity Eigenmodes
File Type: Conference Paper
Issue:Volume: Advances in Finite Difference Time Domain      Number:      Year: 2009
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Title: Using the Feature Selective Validation Technique to Compare Data Sets
File Type: Conference Paper
Issue:Volume: Advances in Numerical EM and Propagation Tools      Number:      Year: 2009
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Title: USING THE FDTD METHOD TO MODEL THE REFLECTION COEFFICIENT OF A VIVALDI TAPERED SLOT ANTENNA FED THROUGH A PLANAR BALUN
Abstract: In this paper, the Time-Domain (FDTD) method was used to determine the reflection coefficient vs. frequency of a Vivaldi Tapered Dual-Slot Antenna fed through a planar balun. The reflection coefficient at the input port of the feed stripline was determined through the separate computation of the reflection coefficient of representation of the antenna section and the scattering matrix of the balun, assuming that the electromagnetic coupling between these sections was negligible. Experimental results, which were obtained on a prototype of this structure, confirmed the validity of the proposed approach and demonstrate that the coupling of the model. [Vol. 12, No. 3 (1997), pp 26-30]
Author(s): G. Biffi Gentili, R Braccini, M. Leoncini, G. Biffi Gentili, R Braccini, M. Leoncini
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
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Title: Using the Best Uniform Approximation with Compression for Efficient Computation of Monostatic Scattering
Abstract: The best uniform approximation method hybridized with Singular Value Decomposition (SVD) is proposed to reduce the time requirement for computation of monostatic Radar Cross Section (RCS). In contrast to our previous work, the traditional best uniform approximation technique is applied to compute the key excitation vectors instead of electric current vectors. Reduction of the number of multiple excitation vectors can lead to significantly reduced computation time. Furthermore, with low-rank property, the key excitation vectors could be further compressed by SVD, resulting in a more efficient method. Numerical results demonstrate that the proposed method is efficient for monostatic RCS calculation with high accuracy.
Author(s): Z. Liu, S. He, X. Zhang, Y. Liu, Y. Zhang
File Type: Journal Paper
Issue:Volume: 29      Number: 11      Year: 2014
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Title: Using System-Theoretical Consideration for Calculating Coupling Effects in Packages
File Type: Conference Paper
Issue:Volume: Advances in CEM Applications I      Number:      Year: 2012
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Title: Using Superformula to Miniaturize CPW Rat Race Coupler
Abstract: This paper proposes a new CPW rat race coupler whose shape has been meandered using the superformula for size reduction. The coupler operates at a center frequency of 1.8 GHz. The size reduction in the proposed design is about 74% as compared to conventional ring rat race coupler. The bandwidth of the proposed coupler defined by |S11| < -15 dB is about 31.6%.
Author(s): A. A. Omar, N. I. Dib
File Type: Journal Paper
Issue:Volume: 33      Number: 12      Year: 2018
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Title: USING NONUNIFORM SEGMENTS LENGTHS WITH NEC TO ANALYZE ELECTRICALLY LONG WIRE ANTENNAS
Abstract: In this paper an electrically long monopole is analyzed using the Numerical Electromagnetics Code, version two (NEC-2). Due to the electrical length of the monopole and the segment length requirement established for the NEC-2 program, the computer memory requirement and computational time become excessive. By successively increasing the segment length with distance from the source, very large structures can be analyzed accurately and efficiently. Various schemes for selecting the segment lengths are considered, and the results are compared to those obtained by using a large number of electrically short segments. This technique of grading segment lengths allows one to employ NEC-2 to analyze other electrically long wire antennas. [Vol. 5, No. 2, pp. 2-16 (l990)]
Author(s): Saad N. Tabet, J. Patrick Donohoe, Clayborne D. Taylor, Saad N. Tabet, J. Patrick Donohoe, Clayborne D. Taylor
File Type: Journal Paper
Issue:Volume: 5      Number: 2      Year: 1990
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Title: Using Near Field Equivalent Sources in Combination with Large Element Physical Optics to Model a Slant 45 Degree Omni Directional Antenna over Ground
File Type: Conference Paper
Issue:Volume: S03 EM Modeling using Feko/WinProp      Number:      Year: 2020
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Title: Using Near Field Equivalent Sources in Combination with Large Element Physical Optics to Model a Slant 45 Degree Omni Directional Antenna over Ground
Abstract: This paper compares the theoretical and measured antenna patterns of a slant 45-degree antenna on a rolled edge ground plane. Advantages of using sampled nearfield currents in combination with large element physical optics in determining the reflected far fields will be described.
Author(s): K. Snyder
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: Using Measurements as Field Sources in Computational Electromagnetics Abstract
File Type: Tutorial Abstract
Issue:Volume: S33 Using Measurements as Field Sources in Computational Electromagnetics      Number:      Year: 2015
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Title: Using MATLAB’s Parallel Processing Toolbox for Multi-CPU and Multi-GPU Accelerated FDTD Simulations
Abstract: MATLAB is a good testbed for prototyping new FDTD techniques as it provides quick programming, debugging and visualization capabilities compared to lower level languages such as C or FORTRAN. However, the major disadvantage of using MATLAB is its slow execution. For faster simulations, one should use other programming languages like Fortran or C with CUDA when utilizing graphics processing units. Development of simulation codes using these other programming languages is not as easy as when using MATLAB. Thus the main objective of this paper is to investigate ways to increase the throughput of a fully functional finite difference time domain method coded in MATLAB to be able to simulate practical problems with visualization capabilities in reasonable time. We present simple ways to improve the efficiency of MATLAB simulations using the parallel toolbox along with the multi-core central processing units (CPUs) or the multiple graphics processing units (GPUs). Native and simple MATLAB constructs with no external dependencies or libraries and no expensive or complicated hardware acceleration units are used in the present development.
Author(s): A. J. Weiss, A. Z. Elsherbeni, V. Demir, M. F. Hadi
File Type: Journal Paper
Issue:Volume: 34      Number: 5      Year: 2019
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Title: Using MATLAB to Model Inhomogeneous Media in Commercial Computational Electromagnetics Software
Abstract: This paper presents a new method to model inhomogeneous media in commercial electromagnetics software, especially FEKO. In this method, the inhomogeneous medium is fragmented to some homogeneous pieces. If the size of these pieces is chosen correctly, then the electromagnetic behaviors of them and inhomogeneous medium are the same. Since creating these homogeneous pieces in FEKO manually is very difficult and time consuming, MATLAB is employed to create these pieces in FEKO.
Author(s): A. Farahbakhsh, D. Zarifi, A. Abdolali
File Type: Journal Paper
Issue:Volume: 30      Number: 9      Year: 2015
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Title: 3B-SPLINES IN THE INTEGRAL EQUATION SOLUTION FOR SCATTERING FROM BODIES OF REVOLUTION
Abstract: The use of B-Splines functions is investigated in conjunction with the Method of Moments integral-equation solution to the problem of scattering from conducting bodies of revolution. Its computational performance in terms of relative accuracy and storage/CPU time requirements is evaluated against entire-domain and sampling-like basis functions. Particular attention is given to the description of current near edges. Questions of time (space) and frequency (wavenumber) localization are also addressed. A simple scheme devised to enforce boundary conditions a priori is shown to potentially capable to stgabilize otherwise spurious solutions
Author(s): F.L. Teixeira, J.R. Bergmann, F.L. Teixeira, J.R. Bergmann
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: ELECTROMAGNETIC PROPERTIES OF A CHIRAL-PLASMA MEDIUM
Abstract: The theoretical properties of a composite chiral-plasma medium are devel- oped. Using the reaction theorem, we obtain the proof of nonreciprocity based upon the constitutive relationships between the electromagnetic vectors E, B, H, D. Using the Maxwell's equations and the proposed constitutive relations for a chiral- plasma medium, we derive the E, and H, vector equations and from these equations, dispersion relations and E-field polarizations are found. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 14-18] MTRT - A MODIFIED TRANSVERSE RESONANCE TECHNIQUE
Author(s): Hector Torres-Silva, Norma Reggiani, Paulo H. Sakanaka, Hector Torres-Silva, Norma Reggiani, Paulo H. Sakanaka
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: MTRT - A MODIFIED TRANSVERSE RESONANCE TECHNIQUE
Abstract: In this work a modified formulation of the transverse resonance technique (TRT) is presented. The difference between the usual TRT and the formulation presented here, MTRT, is the equivalent network considered. With the MTRT proposed formulation, mode solution identification requires less arduous work. The complete equation set is described. Numerical results are presented for dispersion characteristics of microstrip lines, coupled microstrip lines and conductor-backed coplanar waveguides (CBCW). When compared to results obtained by other methods, a good agreement is observed. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 19-25]
Author(s): Alfredo Gomes Neto, Creso S. da Rocha, Herve' Aubert Aubert, D. Bajon, H. Baudrand, Alfredo Gomes Neto, Creso S. da Rocha, Herve' Aubert Aubert, D. Bajon, H. Baudrand
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: EFFECT OF THE MAGNETIC ANISOTROPY ON THE CHARACTERISTICS OF MICROSTRIP ANTENNAS WITH SEVERAL LAYERS
Abstract: The main objective of this work is to show how the properties of a ferrimagnetic material change the characteristics of a microstrip patch with several layers. Particularly, it is investigated how the resonant frequency and the radiation pattern are changed by varying the ferrimagnetic layer thickness or the magnitude and/or direction of the external applied magnetic field. The analysis is carried on by using Hertz potentials and Galerkin method. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 26-29]
Author(s): Jose de Ribamar Silva Oliveira, Adaildo Gomes d'Assunc o, Jose de Ribamar Silva Oliveira, Adaildo Gomes d'Assunc o
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: DISPERSIVE ANALYSIS OF CIRCULAR CYLINDRICAL MICROSTRIPS AND BACKED SLOTLINES
Abstract: In this work, the full-wave analysis of circular cylindrical microstrips and backed slotlines is performed, by using a combination of Hertz vector potentials and Galerkin method. The analysis is developed in the spectral domain. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 30-33]
Author(s): Laercio Martins de Mendonca, Adaildo Gomes d'Assunc o, Laercio Martins de Mendonca, Adaildo Gomes d'Assunc o
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: FINITE ELEMENT ANALYSIS AND EVALUATION OF ELECTROMAGNETIC FIELDS GENERATED BY ATMOSPHERIC DISCHARGES
Abstract: A lightning return stroke channel is modeled by a high loss transmission line. The differential equations that represent its dynamic behavior are solved by the application of the one-dimensional finite element method (FEM). By the combination of FEM results with the use of Maxwell equations applied to the dipole method, electric and magnetic (EM) fields are evaluated at various positions in space. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 34-38]
Author(s): E.H.R Coppoli, R.R. Saldanha, A. Konrad, E.H.R Coppoli, R.R. Saldanha, A. Konrad
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: POINT-MATCHED TIME DOMAIN FINITE ELEMENT METHOD APPLIED TO MULTI-CONDUCTOR ELECTROMAGNETIC TRANSIENTS ANALYSIS.
Abstract: A point-matched time domain finite element method (TDFE) applied to the analysis of electromagnetic transients in multi-conductor transmission line network is presented. The TDFE method solves the partial differential transmission line equations based on a semi-discrete approximation using the finite element method and leap-frog scheme. Some oscillations can occur due to the stability condition of the technique. Using the modal analysis these oscillations can be eliminated. A surge propagation in a simple multi-conductor network is presented and the results are compared with the Electromagnetic Transients Program (EMTP) simulations. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 39-43]
Author(s): Glassio Costa de Miranda, Glassio Costa de Miranda
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: ERROR ESTIMATORS IN SELF-ADAPTIVE FINITE ELEMENT FIELD CALCULATION
Abstract: The aim of this paper is to present different error estimates to improve accuracy in linear and nonlinear self-adaptive finite element field calculation. The first estimator is based on the polynomial theory, the second one makes an estimation of the flux density divergence, the third one is linked to a magnetomotive force associated to elements sides, and the fourth one is based on the use of the bilinear element. All methods were implemented in our software named LMAG2D developed at "Escola Politecnica da Universitade de S o Paulo", Brazil. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 44-49]
Author(s): L. Lebensztajn, J.R. Cardoso Cardoso, L. Lebensztajn, J.R. Cardoso Cardoso
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: TRANSIENT VOLTAGE AND ELECTRIC FIELD DISTRIBUTIONS IN AIR CORE REACTORS
Abstract: This work presents a computational model for the evaluation of transient voltage and longitudinal electric field distributions in single layer air core reactors. The influence of a grounded shielding concentric to the reactor is considered. The validity of the model is verified by comparing computed and measured voltage responses at three taps of a test reactor. Analyses showing the influence of the grounded shielding, front time and front wave shape of the applied voltage on the maximum longitudinal electric stresses along the reactor winding are presented. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 50-55]
Author(s): S. L. Varricchio, N. H. C. Santiago, S. L. Varricchio, N. H. C. Santiago
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: CALCULATION OF ELECTRIC FIELD CREATED BY TRANSMISSION LINES, BY 3D-FE METHOD USING COMPLEX ELECTRIC SCALAR POTENTIAL
Abstract: This paper presents a methodology for tridimensional analysis of the electric field produced by transmission lines. It utilizes the complex electric scalar potential, which makes it possible to consider variation of module and phase in the voltages of supply lines. The Finite Element Method (FEM) is applied to solve the differential equation that describes the phenomenon in the domain of this study. Finally, a comparison is established between the results obtained applying the proposed methodology and the values reached through the classical method of charge simulation. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 56-60]
Author(s): Ricardo Marcal Matias, Adroaldo Raizer, Ricardo Marcal Matias, Adroaldo Raizer
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: ADAPTIVE FINITE ELEMENT MESH REFINEMENT AND 'A POSTERIORI' ERROR ESTIMATION PROCEDURES FOR ELECTROMAGNETIC FIELD COMPUTATION
Abstract: Adaptive Finite Element (FE) mesh refinement combined with a robust and functionally reliable error estimate provides nearly optimal solution accuracy. The efficiency of adaptivity depends on the effectiveness of the mesh refinement algorithm and also on the availability of a reliable and computationally inexpensive error estimation strategy. An adaptive mesh refinement algorithm utilizing a hierarchical minimal tree based data structure for 2D and 3D problems is discussed in this paper. Two different 'a posteriori' error estimation schemes, one based on the local element by element method and the other using the gradient of field approach are also presented. The usefulness of the mesh refinement algorithm and the error estimation strategies are demonstrated by adaptively solving a set of 2D and 3D linear boundary value problems. The performance of the error estimates is also verified for adaptive modeling of a nonlinear problem involving the design of a permanent magnet synchronous machine. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 61-68
Author(s): K.C. Chellamuthu, Natan Ida, Q.k. Zhang, K.C. Chellamuthu, Natan Ida, Q.k. Zhang
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: DESIGN OF ELECTRICAL MACHINES AIDED BY FIELD CALCULATION AND FACTORIAL EXPERIMENTS METHOD
Abstract: An approach for electrical machines design by using magnetic field computation coupled to factorial experiments is presented in this paper. Principles of factorial experiments are briefly reviewed and their application to design optimisation is explained. In this application experiments are replaced by magnetic field calculations. The procedure, which performs automatically all the numerical field calculations required, is described. The whole procedure is applied to a typical problem concerning permanent magnets synchronous motor with polar pieces. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 69-73]
Author(s): C. Pertusa, S.Astier, Y.Lefevre, M.Lajoie-Mazenc, C. Pertusa, S.Astier, Y.Lefevre, M.Lajoie-Mazenc
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: LIMITATIONS OF THE CONVENTIONAL METHODS OF FORCE AND TORQUE PREDICTION
Abstract: The calculation of forces and torques developed in electromechanical devices, and their variation with changes in position or excitation, is often what the designer is, ultimately, interested in. This paper addresses some of the problems associated with the force and torque calculations based on numerical field solutions for 2-D magnetostatic problems. The problem of calculating the cogging torque characteristic of a neodymium-iron-boron permanent-magnet motor is considered and the technique of torque measurement is described briefly. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 74-79]
Author(s): Antonio Flavio Licari o Nogueira, Antonio Flavio Licari o Nogueira
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: COMPARISON OF CONVERGENCE RATES OF EDGE AND NODAL FINITE ELEMENTS FOR MAGNETOSTATIC PROBLEMS
Abstract: Mathematical theory is used to obtain convergence estimations for magnetostatic formulations using nodal and edge elements. Numerical results of two closed boundary problems that confirm the theory are presented. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 80-83]
Author(s): M. L. y Gonzalez, R. C. MesquitaM. L. y GonzalezMesquita, J. P. A. Bastos, M. L. y Gonzalez, R. C. MesquitaM. L. y GonzalezMesquita, J. P. A. Bastos
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: FINITE ELEMENT SIMULATION OF AN OUT-OF-PHASE SYNCHRONIZATION OF A SYNCHRONOUS MACHINE
Abstract: This paper presents the finite element simulations of the out-of-phase synchronization of a synchronous machine with an external electric system. Two cases were analysed regarding to the phase angle: 120 and 180 . Computed results are analysed and compared to analyticalvalues.[Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 84-89]
Author(s): Silvio Ikuyo Nabeta, Albert Foggia, Jean-Louis Coulomb, Gilbert Reyne, Silvio Ikuyo Nabeta, Albert Foggia, Jean-Louis Coulomb, Gilbert Reyne
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: A 3D FINITE-ELEMENT COMPUTATION OF STATOR END-WINDING LEAKAGE INDUCTANCE AND FORCES AT STEADY STATE OPERATING CONDITIONS IN LARGE HYDROGENERATORS
Abstract: The forces acting on the stator end windings of a hydrogenerator at steady state operating conditions, as well as the end-winding leakage inductance, are calculated using a 3D finite element package. A more realistic representation for the geometry of the windings and boundaries is considered. The effects of different representations for the stator core end surface are outlined. The computed values of the inductance from time harmonic and static simulations are presented and compared with classical analytical methods. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 90-96]
Author(s): Viviane Cristine Silva, Albert Foggia, Viviane Cristine Silva, Albert Foggia
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: IMPROVING THE CHARGE SIMULATION METHOD FOR THE COMPUTATION OF HIGH VOLTAGE ELECTRIC FIELDS WITH EFFICIENT LEAST SQUARES TECHNIQUES
Abstract: The well known Charge Simulation Method, which is commonly used for electric field calculations, is shown to be a particular and ill-conditioned case of the Least Squares Charge Simulation Method. By solving a practical problem, it is shown how to efficiently handle a least squares problem, thus obtaining results of higher precision if compared to the traditional Charge Simulation Method For the solution of the resulting linear system, several mathematical methods are analyzed and compared, being stated that the optimum combination of higher precision, lesser error propagation, lesser CPU time and lesser computer RAM are simultaneously reached when applying the Least Squares Charge Simulation Method, solved with the QR decomposition and Householder transformations. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 97-102]
Author(s): J. N. Hoffmann, P. Pulino, J. N. Hoffmann, P. Pulino
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: A HYBRID FINITE DIFFERENCES, AND CHARGE SIMULATION METHOD FOR THE COMPUTATION OF HIGH VOLTAGE ELECTRIC FIELDS
Abstract: A new treatment is proposed to the hybrid method of Finite Differences and Charge Simulation for the computation os electric fields, entirely applicable to the similar hybrid method of Finite Element and Charge Simulation. The resulting system of linear equations is solved by using the fixed point theory, the QR decomposition and the Conjugate Gradients Squared method with a preconditioning technique. New procedures are suggested for the discretization of the boundary conditions, which lead to results with higher precision. Case studies are included. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 103-110]
Author(s): J. N. Hoffmann, P. Pulino, J. N. Hoffmann, P. Pulino
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: FINITE ELEMENT MODELING OF ELECTRICAL MACHINES BY SIMULTANEOUS RESOLUTION OF FIELDS AND ELECTRIC CIRCUITS EQUATIONS
Abstract: In this work, we present a methodology for solving simultaneously the equations of magnetic fields and electric circuits of electrical machines. To consider the magnetic phenomena the Finite Element method is used. The machines are voltage fed and, thus, the electric circuit equations are present in the matricial system which takes into account both physical aspects. A time stepping technique is employed to simulate the steady and transient states. As result, we obtain the magnetic vector potential describing the magnetic behavior of the machine and the current established in the exciting coils. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 111-116]
Author(s): N. Sadowski, R. Carlson, J. P. A. Bastos, M. Lajoie-Mazenc, N. Sadowski, R. Carlson, J. P. A. Bastos, M. Lajoie-Mazenc
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: SHAPE DESIGN OPTIMIZATION OF POWER FREQUENCY ELECTROMAGNETIC DEVICES USING NUMERICAL METHODS
Abstract: This paper presents the mathematical formulation concerning the solution of inverse electromagnetic problems, i.e. the shape optimization of power frequency electromagnetic devices, based on a combination of numerical methods. The optimization problem is solved using deterministic methods in which the electromagnetic field problem is treated as a subproblem of the optimization process. The field problem is calculated using the finite element (FE) method. Three deterministic approaches are studied in detail, the quadratic extended penalty method (QUA), the augmented Lagrange multiplier (ALM) method and the constrained quasi-Newton method (PLBA-CR). The work highlights the advantages and drawbacks of each approach. The search direction for the optimization is found by two distinct methods, the direct differentiation of the FE matrices and the finite difference (FD) method. In total, three problems are discussed in order to show the power and applicability of the theory presented. The PLBA-CR, when combined with the direct differentiation of the FE matrices, appears to offer important advantages over the other methods. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 117-124]
Author(s): Jaime A. Ramirez, Ernest M. Freeman, C. Chat-uthai, Jo o A. Vasconcelos, Jaime A. Ramirez, Ernest M. Freeman, C. Chat-uthai, Jo o A. Vasconcelos
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: DETERMINATION AND ANALYSIS OF CAUSES OF INDUCTION MOTOR MAGNETIC NOISE
Abstract: This paper presents the causes of the acoustic noise magnetically generated by three-phase induction electric motors and some results of tests and calculation are discussed. The influence of the rotor slots skewing on the reduction of the magnetic noise is also analysed through calculated values. The paper gives a general view about how the magnetic noise in induction motors is generated and how much its prevision is important during the design stage. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 125-131]
Author(s): Sebasti o Lauro Nau, Solon Brum Silveira, Sebasti o Lauro Nau, Solon Brum Silveira
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: GROUND-3D LINKED TO LINE PARAMETERS: A METHOD TO FAULT CURRENT DISTRIBUTION AND EARTH POTENTIAL DETERMINATION
Abstract: In previous work [1,2] the author presents a methodology, based on finite elements method (FEM), to calculate the potential distribution influence on the grounding area. At that time the input of the solver admits as known the split of the system. The aim of this article is to demonstrate the advantages of finite element method (FEM) associated with power systems equations with lumped parameters to intrinsically obtain the distribution of fault current in several offered conductor ways and the potential distribution on the ground, simultaneously. To solve the complex equations system, the methodology adopted was that described by Mesquita [3]. . [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 132-135]
Author(s): H. O. Brodskyn, M. C. Costa, J. R.Cardoso, N. M. Abe, A. Passaro, H. O. Brodskyn, M. C. Costa, J. R.Cardoso, N. M. Abe, A. Passaro
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: AN INVESTIGATION OF THE SCATTERING OF SURFACE WAVES AT DIELECTRIC SLAB WAVEGUIDE WITH AXIAL DISCONTINUITY
Abstract: This paper introduces a technique for studying the radiation due to an abrupt axial discontinuity in the geometry of a planar dielectric waveguide (Slab waveguide) when an even TM surface wave strikes the discontinuity. The mode matching technique is applied at the discontinu- ity giving rise to formally exact integral equations which are solved by the Method of Moments. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 136-141]
Author(s): Creso S. Da Rocha, Creso S. Da Rocha
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: ADAPTIVE MESHING IN TWO-VARIABLE STATIC PROBLEMS WITH FIELD BASED ERROR ESTIMATORS USING EDGE AND FACET ELEMENTS
Abstract: In this paper a family of field-based error estimators for Finite Element analysis of electrostatic and magnetostatic problems in plane and axisymmetric geometries is presented. For the error estimation in magnetostatics, each element is divided in three sub-elements using an edge element approach, whereas for electrostatic problems a subdivision using facet elements is used. The methods and the numerical techniques are described, comparisons with known solutions are performed, some examples of application in cases of practical interest are reported and the obtained results are briefly discussed. . [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 142- 147]
Author(s): P. Girdinio, P. Molfino, G. Molinari, M. Nervi, P. Girdinio, P. Molfino, G. Molinari, M. Nervi
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: FINITE ELEMENT MODELLING SCHEMES FOR THE DESIGN AND ANALYSIS OF ELECTRICAL MACHINES
Abstract: Electrical machines are complex objects. We have found that a variety of numerical techniques are required in order to model them using finite elements. We concentrate here on the different formulations which are useful in modelling such devices. Examples of modelling some of these machines using the MEGA package are described. . [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 148- 152]
Author(s): D.Rodger, P.J. Leonard, H.C. Lai, N. Allen, D.Rodger, P.J. Leonard, H.C. Lai, N. Allen
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: THREE DIMENSIONAL MAGNETOSTATICS USING THE MAGNETIC VECTOR POTENTIAL WITH NODAL AND EDGE FINITE ELEMENTS
Abstract: In this paper, the three dimensional vector potential magnetostatic problem is solved using nodal and edge finite elements. The influence of the gauge condition A.w=0 in the characteristics of the edge-element generated matrix is analyzed. Three gauge conditions are studied: no gauge, the complete A.w=0 gauge and the incomplete A.w=0 gauge condition. [Vol. 12, No. 1 (1997), Special Issue on International Computational Electromagnetics, pp 153-156]
Author(s): E. J. Silva, R. C. Mesquita Mesquita, E. J. Silva, R. C. Mesquita Mesquita
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: A NEW ITERATIVE MOMENT METHOD SOLUTION FOR CONDUCTING BODIES OF REVOLUTION
Abstract: An iterative solution of the combined field integral equation (CFIE) has been obtained for perfectly conducting bodies. The proposed technique avoids the inversion of the moment method (MoM) matrix by using an iterative algorithm which shows fast convergence properties, mainly for large bodies. The algorithm is applied to several 3D problems involving bodies of revolution (BOR). Accurate currents are computed with important speedups over direct MoM solutions. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 6-10]
Author(s): F. Obelleiro, J. L. Rodriguez, A. G. Pino, F. Obelleiro, J. L. Rodriguez, A. G. Pino
File Type: Journal Paper
Issue:Volume: 12      Number: 1      Year: 1997
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Title: CALCULATION OF THE FREQUENCY CHARACTERISTICS OF MICROSTRIPS DISCONTINUITIES ON NON-DIAGONAL ANISOTROPIC SUBSTRATES USING FDTD
Abstract: This paper describes modifications of the conventional finite-difference time-domain (FDTD) method to the full-wave analysis of frequency dependent characteristics of microstrips discontinuities on non-diagonal anisotropic substrates. The application of the conventional FDTD is limited to materials with diagonal-anisotropic material matrices. In this paper it is shown that this restriction can be removed: First, steps for obtaining the FDTD equations for the analysis of microstrips discontinuities on substrates with fully anisotropic permittivity matrices are derived. Then, using the Fourier transform of the computed results in the time-domain, the scattering parameters as functions of the frequency are calculated for several examples. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 11-15]
Author(s): S. M. Chehrehrazi, A. R. Baghai-Wadji, S. M. Chehrehrazi, A. R. Baghai-Wadji
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: ELECTROMAGNETIC WAVES IN A NONLINEAR DISPERSIVE SLAB
Abstract: The electromagnetic scattering of a normal incident plane wave from a strongly nonlinear and dispersive dielectric slab is considered. The dynamics of the polarization density vector are described through a forced nonlinear ordinary differential equation of Duffing type, which takes both dispersive and nonlinear effects into account. The aim of the paper is to study the behaviour of the electromagnetic fields by using the Galerkin method. In particular it is shown that shock waves with infinite slope cannot be developed in real media because of the dispersion . [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering pp 16-19]
Author(s): G. Miano, C. Serpico, L. Verolino, G. Panariello, G. Miano, C. Serpico, L. Verolino, G. Panariello
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: SENSITIVITY ANALYSIS USING HIGH ORDER DERIVATIVES
Abstract: In this article, we present a method of sensitivity analysis based on high order derivatives and Taylor expansion. The principle is to find a polynomial approximation of the finite element solution in terms of the sensitivity parameters. We present this method on two dimensional linear magnetostatic and linear magnetodynamic problems. The sensitivity parameters can be either physical parameters or geometric ones. Once the high order derivatives are found, the Taylor expansion allows evaluations for a new set of parameters. The time needed to obtain a new solution is negligible compared to a standard finite element re-analysis. This implies a dramatic change in the use of computational tools. Moreover, the availability of fast evaluations allows a wide use of optimization algorithms. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 20-25]
Author(s): J. L. Coulomb, P. Petin, L. Saludjian, N. Nguyen Thanh, R. Pacaut, J. L. Coulomb, P. Petin, L. Saludjian, N. Nguyen Thanh, R. Pacaut
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: SELF ADAPTIVE FUZZY SETS IN MULTI OBJECTIVE OPTIMIZATION USING GENETIC ALGORITHMS
Abstract: Optimization in electrical engineering has attracted an increasing attention over the last few years. Various strategies to solve electromagnetic optimization problems have been introduced, amongst them stochastic, deterministic and hybrid ones. Most of today's real world applications, however, involve multiple conflicting objectives which should be considered simultaneously. The aim of this paper is to introduce self adaptive fuzzy sets to treat vector optimization problems. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 26-31]
Author(s): Ch. Magele, G. Furntratt, B. Brandstatter, K.R. Richter, Ch. Magele, G. Furntratt, B. Brandstatter, K.R. Richter
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: OPTIMISATION OF THE SHAPE OF THE FERROMAGNETIC CORE OF FLUXSET TYPE MAGNETIC FIELD SENSORS
Abstract: A method is presented for the optimisation of the shape of the ferromagnetic core of fluxset type magnetic filed sensors. The objective of the optimisation is to find a core shape that guarantees the most homogeneous magnetisation of the core due to a given external magnetic field. By finding the optimal shape of the core the sensitivity of the sensor is improved. Since the thickness of the ferromagnetic conducting ribbon core used for fluxset sensors is considerably smaller than its other dimensions, the presence of the core is modelled by magnetic and conducting surface currents flowing in a mathematical surface representing the core. The electromagnetic field is calculated by solving an integral equation derived from the assumption of impedance type boundary conditions on the two sides of this surface. The core shape is optimised by minimising the magnetisation differences at different locations of the core. Simulated annealing procedure is used for the optimisation. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 32-37]
Author(s): Jozsef Pavo, Jozsef Pavo
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: NUMERICAL TECHNIQUES FOR THE INVERSION OF EDDY CURRENT TESTING DATA
Abstract: In this paper, we discuss two techniques for the reconstruction of conductivity profiles in the low frequency limit. The first one is based on the second order approximation of the scattered field operator. In the second procedure, the problem is linearized at the expense of an increase in the number of unknowns including, in this case, the current density and the electric field. Some simple 2D examples are presented to point out and compare the main features of the two approaches. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 38-43]
Author(s): Guglielmo Rubinacci, Antonello Tamburrino, Guglielmo Rubinacci, Antonello Tamburrino
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: MAGNETIC MATERIAL PROPERTY IDENTIFICATION USING NEURAL NETWORKS
Abstract: In the numerical solution of field problems for many devices, the modeling of the hysteresis properties of a material is extremely important. While considerable work has been published on models for handling this behavior, it is still difficult to obtain the parameters for these models from measured data. This paper proposes the use a neural network for this operation. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 44-49]
Author(s): Hamadou H. Saliah, David A. Lowther, Hamadou H. Saliah, David A. Lowther
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: OPTIMIZATION OF A SMES DEVICE UNDER NONLINEAR CONSTRAINTS
Abstract: In this paper a method to calculate the gradients for the TEAM 22 problem is presented. Furthermore an objective function different from the one proposed in the benchmark is used where the energy requirement was handled as an equality constraint. The so derived gradients of the objective function and the constraints together with a standard optimization routine are used to solve the problem. In the last section some new results concerning the presence of local minima for the problem are given. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 50-53]
Author(s): B. R. Brandstatter, Wolfgang Ring, B. R. Brandstatter, Wolfgang Ring
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: RECONSTRUCTION OF INHOMOGENEOUS LOSSY DIELECTRIC OBJECTS IN ONE DIMENSION
Abstract: The 1D inverse scattering problem of reconstructing the material properties of an inhomogeneous lossy dielectric slab is considered. The material properties are reconstructed using scattering data from time harmonic electromagnetic plane waves. The incident plane waves are either TE or TM polarized. The inverse scattering problem formulated as a nonlinear optimization problem by means of integral equations is numerically solved using an iterative scheme and Tikhonov regularization. Numerical examples with both types of polarization are presented. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 54-59]
Author(s): W. Rieger, M. Haas, C. Huber, G. Lehner, W.M. Rucker, W. Rieger, M. Haas, C. Huber, G. Lehner, W.M. Rucker
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
Download Link:Click here to download PDF     File Size: 506 KB

Title: LAGRANGIAN BEM-FEM SOLUTION OF ELECTROMAGNETIC-MECHANICAL COUPLED PROBLEMS
Abstract: In the framework of the electro-mechanical coupled problems, the coupling between the magnetic diffusion and the elastic deformation equations is treated numerically. A mixed BEM-FEM approach for the electromagnetic part, and a FEM approach for the mechanical part, are proposed. Advantages are taken from a Lagrangian formulation of the problem. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 60-65]
Author(s): A. Formisano, R. Martone, F. Villone, A. Formisano, R. Martone, F. Villone
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: MODELLING OF DEGAUSSING COILS EFFECTS ON SHIPS
Abstract: This paper presents our work on magnetic modelling of ships, especially their degaussing coils. We first focus on these coils effects in the FEM computations. The main reason of bad results is a locally inadequate mesh. We propose a method named " reduced potential jump" to avoid the use of a very fine mesh. Then, comparison of results is presented for a simple geometry. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 66-70]
Author(s): F. Le Dorze, J. P. Bongiraud, J. L. Coulomb, G. Meunier, X. Brunotte, F. Le Dorze, J. P. Bongiraud, J. L. Coulomb, G. Meunier, X. Brunotte
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: A THREE-DIMENSIONAL ANALYSIS OF MAGNETIC SHIELDING WITH THIN LAYERS
Abstract: This paper describes a numerical method for the analysis of the magnetic shielding with thin layers in three dimensional, time-harmonic magnetic fields. In this method, FEM is employed to solve a couple of differential equations which express the surface impedance of the thin shielding materials. The magnetic fields in air regions are modeled by means of BEM. The above formulations are coupled to evaluate the shielding properties. The resultant matrix equation includes unknowns of two times the number of nodal points. This method can analyze not only a shielding system with closed surfaces but also that with open surfaces without
Author(s): H. Igarashi, T. Honma, A. Kost, H. Igarashi, T. Honma, A. Kost
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: A C.A.E. TOOL TO UNDERSTAND MAGNETOSTATICS
Abstract: We present in this paper a Computer Aided Education package allowing to visualize the magnetostatic field in and around the magnetic circuit of a double-U shaped contactor. The modeling of this device is performed by solving in real time a non-linear finite element problem. The imple- mentation of this method is optimized greatly in order to allow to animate field patterns in real time in reaction to any user interaction. An evaluation of the improvements brought by this technique to the learning capabilities of students is presented. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 81-84]
Author(s): F. Buret, D. Muller, A. Nicolas, L. Nicolas, F. Buret, D. Muller, A. Nicolas, L. Nicolas
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: NUMERICAL MODELLING OF AN AXIAL-FIELD SOLID DISK INDUCTION MACHINE
Abstract: In this paper a method for the steady-state analysis of an axial-field induction motor with a solid disk rotor is proposed. The boundary condition for the axial component of the magnetic flux density has been calculated by means of an analytical procedure. Accordingly the simulation region is restricted to the air-gap and the rotor. Then the axial component of the diffusion equation is solved for by using a finite difference scheme. Subsequently the azimuthal component of the magnetic flux density and the current density induced in the rotor come out from the field's laws. The validity of the proposed method has been tested by comparing the numerical results with data measured on a double-stator prototype. Finally the numerical procedure has been used for the analysis of the performance of a motor for light vehicle propulsion and the results of the simulation are shown. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 85- 89]
Author(s): Marco Angeli, Nunzio Esposito, Antonino Musolino, Bernardo Tellini, Marco Angeli, Nunzio Esposito, Antonino Musolino, Bernardo Tellini
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: MODELLING DYNAMIC HYSTERESIS IN FERROMAGNETIC SHEETS UNDER TIME-PERIODIC SUPPLY CONDITIONS
Abstract: This paper presents an application of the Dynamic Preisach Model as proposed by Bertotti, to the analysis of electromagnetic phenomena inside a ferromagnetic lamination subject to imposed time-periodic magnetic flux. The field problem, considered as one dimensional, is formulated in terms of magnetic field and the Fixed Point technique is used for the treatment of the hysteretic nonlinearity. The solution is carried out in the harmonic domain by means of the Finite Element method. The original implementation of the Dynamic Preisach Model is detailed and comparisons with measurements are presented in the case of sinusoidal excitations. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 90-95]
Author(s): Oriano Bottauscio, Mario Chiampi, Maurizio Repetto, Oriano Bottauscio, Mario Chiampi, Maurizio Repetto
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: DYNAMIC OPERATION OF COILS WITH FERROMAGNETIC CORES TAKING MAGNETIC HYSTERESIS INTO ACCOUNT
Abstract: The computation of electromagnetic field diffusion in ferromagnetic and conductive media is coupled to circuit analysis problems, involving coils with iron cores. The classical Preisach model provides the relationship between magnetic field intensity and flux density at the local level, inside the core. Combined with a 2D eddy current simulation, carried out by a time stepping method, the dynamic operation of the core is modelled. The circuit equations are solved taking the effects of hysteresis and skin effects caused by eddy currents induced in core sheets into account. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 96-101]
Author(s): Janos Fuzi, Janos Fuzi
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: A STRONG COUPLING MODEL FOR THE SIMULATION OF MAGNETOMECHANICAL SYSTEMS USING A PREDICTOR/MULTI-CORRECTOR ALGORITHM
Abstract: A recently developed modeling scheme for the numerical simulation of coupled magnetomechanical systems is presented. The scheme allows the calculation of dynamic rigid motions as well as deformations of magnetic and anti-magnetic materials in a magnetic field. The equations governing the magnetic and mechanical field quantities are solved using a combined Finite Element /Boundary-Element-Method (FEM-BEM). To circumvent the nonlinear system of equations resulting from a direct coupling of the magnetic and mechanical systems, the calculation of the magnetic forces is based on predictor values of the magnetic quantities. Therewith, a decoupling into a magnetic and mechanical matrix equation can be achieved. To ensure the strong coupling between the magnetic and mechanical quantities, a sophisticated Predictor/Multicorrector Algorithm is used resulting in an efficient iteration between the two matrix equations within a single time step. Computer simulations of an electromagnetic forming system and a magnetomechanical transducer immersed in an acoustic fluid (acoustic power source) show good agreement between simulation results and measured data. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 102-106]
Author(s): M. Kaltenbacher, H. Landes, R. Lerch, M. Kaltenbacher, H. Landes, R. Lerch
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: RESULTS OF PARALLELISATION OF EXISTING ELECTROMAGNETIC FINITE ELEMENT CODES ON SOME DIFFERENT PARALLEL ARCHITECTURES
Abstract: In this paper the results obtained from the parallelisation of some 3D industrial electromagnetic Finite Element codes within the ESPRIT Europort 2 project PARTEL are presented. The basic guidelines for the parallelisation procedure, based on the Bulk Synchronous Parallel approach, are presented and the encouraging results obtained in terms of speed-up on some selected test cases of practical design significance are outlined and discussed. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 107-112]
Author(s): M. Dracopoulos, K. Palrot, G. Molinari, M. Nervi, J. Simkin, M. Dracopoulos, K. Palrot, G. Molinari, M. Nervi, J. Simkin
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: THE NEWTON-RAPHSON METHOD FOR COMPLEX EQUATION SYSTEMS
Abstract: A formulation for the complex Newton-Raphson method is proposed. The derivation is obtained on the assumption of a non-analytical system. The method is applied to the finite element calculation of shielding problems with sinusoidal ex-citation and ferromagnetic material. An application example for which measurement data are available is given in order to judge the convergence characteristics and the reliability of the proposed method. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 113-116]
Author(s): Dieter Lederer, Hajime Igarashi, Arnulf Kost, Dieter Lederer, Hajime Igarashi, Arnulf Kost
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: SOME ASPECTS OF MAGNETIC FORCE COMPUTATION USING BEM-FEM COUPLING
Abstract: For the calculation of magnetic forces with the Maxwell stress tensor the normal and the tangential derivatives of the vector potential A have to be known. We choose Co-continuous elements, therefore A and its tangential derivatives are continuous. In contrast, the normal derivative A/ n calculated with the finite element method is continuous only in a weak sense. When BEM-FEM coupling is used however, the value of A/ n is uniquely available on the coupling surfaces from the BEM formulation. Two methods of magnetic force computation using A/ n either from FEM or from BEM data will be presented. Their accuracy will be compared by means of several examples. [Vol. 12, No. 2 (1997), pp Special Issue on Numerical Field Calculations in Electrical Engineering, 117-120]
Author(s): Joachim Fetzer, Stefan Kurz, Gunther Lehner, Wolfgang M. Rucker, Joachim Fetzer, Stefan Kurz, Gunther Lehner, Wolfgang M. Rucker
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: THE NUMERICAL TREATMENT OF SINGULAR INTEGRALS IN BOUNDARY ELEMENT CALCULATIONS
Abstract: In this paper a general method for the evaluation of singular boundary element integrals over three-dimensional isoparametric boundary elements of higher order is presented. This method permits an efficient integration of strongly singular kernels of order O(1/r2) and of nearly strong singular kernels on curved surfaces. For numerical examples the proposed integration scheme is compared with analytical test examples showing high efficiency and accuracy. This new method has full generality and, therefore, can be applied in any field of electromagnetics. The actual computation can be easily included in any existing computer code, e. g. for the solution of electromagnetic scattering problems. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 121-126]
Author(s): C.J. Huber, W. Rieger. M. Haas, W.M. Rucker, C.J. Huber, W. Rieger. M. Haas, W.M. Rucker
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: MODELLING EDDY CURRENTS INDUCED BY ROTATING SYSTEMS
Abstract: As part of a Japanese funded project, a transient eddy current code is being extended to allow for rotational systems. By allowing the system to rotate, induced eddy currents must be modelled. The system being developed uses the "lock-step" approach to model the rotation. As other facilities are included (non-linear materials for example), the solution time of the final code becomes sufficiently large that special care must be taken, and investigations into using parallel hardware becomes necessary. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 131-134]
Author(s): C. R. I. Emson, C. P. Riley, D. A. Walsh, C. R. I. Emson, C. P. Riley, D. A. Walsh
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: BEM-FEM COUPLING IN ELECTROMECHANICS: A 2-D WATCH STEPPING MOTOR DRIVEN BY A THIN WIRE COIL
Abstract: This paper deals with the transient numerical analysis of 2-d electromechanical devices driven by thin wire coils. Their dynamical behavior is described by the Maxwell equations, by the constitutive relations, and by the equations of motion. For the solution of the electromagnetic problem the BEM-FEM coupling method is used. A two- dimensional watch stepping motor is presented as an example. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 135-139]
Author(s): Stefan Kurz, Joachim Fetzer, Thomas Kube, Gunther Lehner, Wolfgang M. Rucker, Stefan Kurz, Joachim Fetzer, Thomas Kube, Gunther Lehner, Wolfgang M. Rucker
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: HYBRID FORMULATIONS FOR 3D MAGNETOSTATIC AND EDDY CURRENT PROBLEMS
Abstract: Hybrid formulations for solving nonlinear 3D magnetostatic and eddy current problems in terms of magnetic field H are presented. In the pro- posed formulations integral operators are utilized as if the boundary conditions for a partial differential equation were solved within the system of equations. A good correspondence between the results of the presented methods and measurements or other methods is obtained for some test problems. [Vol. 12, No. 2 (1997), Special Issue on Numerical Field Calculations in Electrical Engineering, pp 140-144]
Author(s): Kimmo Forsman, Lauri Kettunen, Kimmo Forsman, Lauri Kettunen
File Type: Journal Paper
Issue:Volume: 12      Number: 2      Year: 1997
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Title: DOMAIN DECOMPOSITION STRATEGIES FOR SOLVING THE MAXWELL EQUATIONS ON DISTRIBUTED PARALLEL ARCHITECTURES
Abstract: Domain decomposition strategies for solving hyperbolic systems of partial differential equations on distributed-memory parallel computing platforms are investigated. The logically-rectangular computational domain is divided either one, two, or three dimensionally into a series of computational blocks, and each block is assigned to a single processor. Theoretical predictions using standard parallel performance models indicate that higher-dimensional decompositions provide superior parallel program performance in terms of scalability. The theory is tested using a finite-volume time-domain (FVTD) Maxwell equations solver to compute the electromagnetic fields inside a rectangular waveguide using various grid sizes and processor numbers on three different parallel architectures- the Intel Paragon, the IBM SP2, and the Cray T3D. The specific performance of the FVTD algorithm on the three machines is investigated, the relation between processor connection topology and message passing performance of a typical grid-based hyperbolic equation solver are identified, and the results are used to augment the classical parallel performance model. Although clear performance trends emerge in terms of the dimensionality of the decomposition, results indicate that higher-dimensional decompositions do not always provide superior parallel performance. [Vol. 12, No. 3 (1997), pp 4-15]
Author(s): Douglas C. Blake, Thomas A. Buter, Douglas C. Blake, Thomas A. Buter
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
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Title: MOMENT METHOD SURFACE PATCH AND WIRE GRID ACCURACY IN THE COMPUTATION OF NEAR FIELDS
Abstract: The accuracy of surface patch and wire grid moment method models for the of near fields is investigated. A sphere and a flat plate with plane wave illumination are examined. It is found that wire grids exhibit stronger near field anomalies than surface patches, which have the current more distributed over the surface. Nevertheless, good results can be obtained with a wire grid, provided that a small distance from the wire grid surface is maintained The surface patch results are obtained using the Junction code. Wire grid results are with both the MBC and NEC codes. Validation the sphere is by comparison with an exact solution obtained from the NECBSC code. [Vol. 12, No. 3 (1997), pp 16-25]
Author(s): Robert Paknys, Leslie R. Raschkowan, Robert Paknys, Leslie R. Raschkowan
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
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Title: FINITE-DIFFERENCE TIME-DOMAIN MODELING OF LIGHT-TRAPPING IN SOLAR CELLS
Abstract: To maximize light-trapping, the absorption of light in the solar cell is maximized. The ways to increase light-trapping are to texture the surfaces of the solar cell and to use anti-reflection coatings. The power spectrum of sunlight also plays an important role in light-trapping. In general, a solar cell consists of multiple layers of dielectric materials. Each dielectric has a complicated surface texture geometry to increase light-trapping. This paper concentrates on solving Maxwell's equations for the general solar cell configuration under illumination from the sun. The absorption and maximum achievable current density are calculated and used to quantify light-trapping in a given solar cell design. Thin solar cells promise to yield higher current collection than thick solar cells at a lower cost [1]. Low cost solar cells are usually characterized by short diffusion length semiconductors. Most minority carriers created within the distance equal to the diffusion length contribute to the electrical current of a solar cell. Hence, the solar cell must be thin when low quality materials are used. As solar cells decrease in size, the ray-trace model becomes inaccurate as previously demonstrated in [2]. A full-wave Finite-Difference Time-Domain (FDTD) light-trapping model is demonstrated to accurately study light-trapping of thin-film solar cells. [Vol. 12, No. 3 (1997), pp 31-42]
Author(s): Todd Marshall, Melinda Piket-May, Todd Marshall, Melinda Piket-May
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
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Title: MODELLING EDDY CURRENTS IN UNBOUNDED STRUCTURES USING THE IMPEDANCE METHOD
Abstract: In this paper extensions to the impedance network method are presented. In particular the method has been applied to problems with boundaries extending to infinity. The infinite boundary condition can also be applied to lines of symmetry in the given geometry. Two dimensional surface models have been verified by comparison of numerical and experimental results in which the potential was measured along the edge of copper sheeting of various shapes located in a uniform, quasi-static magnetic field. The method has potential for modelling three dimensional structures including anisotropic earth planes, arbitrarily shaped buried objects, and both finite and infinitely long faults, dykes, pipes, cylinders and cracks. [Vol. 12, No. 3 (1997), pp 43-49]
Author(s): Daniel James Daniel James, David V. Thiel, Daniel James Daniel James, David V. Thiel
File Type: Journal Paper
Issue:Volume: 12      Number: 3      Year: 1997
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Title: CALCULATION OF ELECTROMAGNETIC SCATTERING VIA VARIATIONS AND ANALYTIC CONTINUATION
Abstract: In this paper we review a numerical method we introduced recently for the solution of problems of electromagnetic scattering. Based on variations of the boundaries of the scatterers and analytic continuation, our approach yields algorithms which are applicable to a wide variety of scattering configurations. We discuss some recent applications of this method to scattering by diffraction gratings and by large two-dimensional bounded bodies, and we present results of new applications to three-dimensional gratings containing corners and edges. In many cases of practical interest our algorithms give nu- merical results which are several orders of magnitude more accurate than those given by classical methods. [Vol. 11, No. 1 (1996), pp 17- 31, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): Oscar P. Bruno, Fernando Reitich, Oscar P. Bruno, Fernando Reitich
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: ERROR CONTROL IN NUMERICAL SOLUTIONS OF BOUNDARY INTEGRAL EQUATIONS
Abstract: A method of estimating the error committed in numerical solutions of integral equations is presented. It is shown how the error can be computed in spaces other than L^2, why this is reasonable and sometimes necessary. The appropriate function spaces are also shown to lead to bounded condition numbers even for first kind equations. [Vol. 11, No. 1 (1996), pp 32-36, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): G . C . HSIAO, R. E . R. E . KLEINMAN, G . C . HSIAO, R. E . R. E . KLEINMAN
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: CALCULATIONS IN MATHEMATICA ON LOW-FREQUENCY DIFFRACTION BY A CIRCULAR DISK
Abstract: This paper is devoted to the symbolic calculation of the scattering coefficient in diffraction by a circular disk, by the use of Mathematica. Three diffraction problems are considered: scalar diffraction by an acoustically soft disk, scalar diffraction by an acoustically hard disk, and electromagnetic diffraction by a perfectly conducting disk. In the low-frequency approximation, the solutions of these problems are in the form of expansions in powers of ka, where a is the radius of the disk and k is the wave number. The emphasis is on the low-frequency expansion for the scattering coefficient, of which several terms are determined exactly with the help of Mathematica. [Vol. 11, No. 1 (1996), pp 47-56, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): J. Boersma, M. J. H. Anthonissen, J. Boersma, M. J. H. Anthonissen
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: SCATTERING BY LARGE STRUCTURES WITH PERIODIC SURFACES: A PROTOTYPE PROBLEM
Abstract: A hybrid method which uses both numerical and asymptotic techniques is described and applied to the scattering of an electromagnetic wave off a large corrugated circular cylinder. The radius of the cylinder is large compared to the wavelength of the incident radiation, but the corrugation height and period are of the same order as the wavelength. This problem is a prototype of a more general situation where the surface of a target is covered with a periodic coating. The method of attack essentially blends boundary layer theory, which describes the local scattering behavior of the surface, and the theory of geometrical optics which gives a global description of the scattering. Although the hybrid method is only developed here for this simple model, its applicability for other targets is clear. [Vol. 11, No. 1 (1996), pp 57-62, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): G.A. Kriegsmann, G.A. Kriegsmann
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
Download Link:Click here to download PDF     File Size: 428 KB

Title: MONO-STATIC RCS COMPUTATION WITH A BLOCK GMRES ITERATIVE SOLVER
Abstract: We present a new method of computing mono-static radar cross sections using a preconditioned Block GMRES iterative algorithm. The convergence properties of this algorithm are analyzed using RCS error, equation residual error and solution error. It is found that this method is nearly an order of magnitude faster than direct methods (LINPACK) for realistic method of moment problems. [Vol. 11, No. 1 (1996), pp 63-69, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): William E. Boyse, Andrew A. Seidl, William E. Boyse, Andrew A. Seidl
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: MODERN KRYLOV SUBSPACE METHODS IN ELECTROMAGNETIC FIELD COMPUTATION USING THE FINITE INTEGRATION THEORY
Abstract: A theoretical basis for numerical electromagnetics, the so-called Finite Integration Theory, is described. Based upon Maxwell's equations in their integral form, it results in a set of matrix equations, each of which is a discrete analogue of its original analytical equation. Applications of this discretization process are described here in the context of the numerical simulation of electroquasistatic problems and of time-harmonic field computations including a new type of waveguide boundary condition, which is presented here for the first time. In both fields the process of mathematical modelling and discretization yields large systems of complex linear equations which have to be solved numerically. For this task several modern Krylov subspace methods are presented such as BiCG, CGS and their more recent stabilized variants CGS2, BiCGSTAB(I) and TFQMR. They are applied in connection with efficient preconditioning methods. The applicability of these modern methods is shown for a number of examples for both problem types. [Vol. 11, No. 1 (1996), pp 70-84, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): Markus Clemens, Rolf Schuhmann, Ursula van Rienen, Thomas Weiland, Markus Clemens, Rolf Schuhmann, Ursula van Rienen, Thomas Weiland
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: FINITE DIFFERENCE METHODS FOR THE NONLINEAR EQUATIONS OF PERTURBED GEOMETRICAL OPTICS
Abstract: Finite difference methods are developed to solve the nonlinear partial differential equations approximating solutions of the Helmholtz equation in high frequency regime. Numerical methods are developed for solving the geometrical optics approximation, the classical asymptotic expansion, and a new perturbed geometrical optics system. We propose a perturbed geometrical optics system to recover diffraction phenomena that are lost in geometrical optics approximations. We discuss techniques we have developed for recovering multivalued solutions and we present numerical examples computed with finite difference approximations of the above systems. [Vol. 11, No. 1 (1996), pp 90-98, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): E. Fatemi, B. Engquist, and S. Osher, E. Fatemi, B. Engquist, and S. Osher
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: ANALYSIS OF THE FINITE ELEMENT RADIATION MODEL CODE FOR ANTENNA MODELING
Abstract: The Finite Element Radiation Model (FERM) code is applied to examine radiation patterns and input impedance of various antenna con- figurations on complex helicopters. This paper addresses the strengths and weaknesses of the FERM code when applied in antenna analysis and is compared with other national codes, such as the Numerical Electromagnetics Code (NEC). In addition, guidelines are outlined for various applications of the code. [Vol. 11, No. 2 (1996), pp 4-13]
Author(s): Marcos C. Medina, Constantine A. Balanis, Jian Peng, Panayiotis A. Tirkc Panayiotis A. Tirkc, Marcos C. Medina, Constantine A. Balanis, Jian Peng, Panayiotis A. Tirkc Panayiotis A. Tirkc
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
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Title: ACCURACY OF THE FINITE ELEMENT METHOD WITH SECOND ORDER ABSORBING BOUNDARY CONDITIONS FOR THE SOLUTION OF APERTURE RADIATION PROBLEM
Abstract: The Finite Element Method with second order Absorbing Boundary Condition is a recently developed computational technique that finds use in antenna design and Electromagnetic Compatibility simulation. To determine the accuracy of this new procedure, the problem of aperture radiation was studied. The near zone and aperture fields of a waveguide antenna computed using the Finite Element Method are compared with published data and results found using other simulation techniques. These comparisons show that the new method is accurate even when the ABC boundary conforms to the problem geometry and is placed as near as /2pi to the aperture. [Vol. 11, No. 2 (1996), pp 14-23]
Author(s): John Silvestro, Xingchao Yuan, Zoltan Cendes, John Silvestro, Xingchao Yuan, Zoltan Cendes
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
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Title: A MOMENT METHOD FORMULATION FOR THE ANALYSIS OF WIRE ANTENNAS ATTACHED TO ARBITRARY CONDUCTING BODIES DEFINED BY PARAMETRlC SURFACE
Abstract: A Moment Method (MM) technique for the analysis of wire antennas on board resonant-sized bodies modelled with parametric surfaces is presented. The approach may have useful applications for the study of the behaviour of wire antennas on board complex conducting structures like aircrafts. The current is represented by curved rooftop functions on the body, piecewise linear functions on the wires and a new junction function in the attachment region between the body and the antenna. The bodies are precisely defined by means of a small number of NURBS surfaces (Non Uniform Rational B-Splines) and Bezier patches (BP). In addition the new junction function that can be defined over any BP allows the antenna to be attached to any part of the body. Radiation patterns and input impedance calculations for several geometries are presented to show the accuracy of the method. The results are successfully validated when comparisons with measurements or results from other methods are carried out. [Vol. 11, No. 2 (1996), pp 32-39
Author(s): F. Rivas, L. Valle, M.F. Catedra, F. Rivas, L. Valle, M.F. Catedra
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
Download Link:Click here to download PDF     File Size: 534 KB

Title: A POSTERIORI ERROR ESTIMATES FOR TWO-DIMENSIONAL ELECTROMAGNETIC FIELD COMPUTATIONS: BOUNDARY ELEMENTS AND FINITE ELEMENTS
Abstract: A brief summary of the variational boundary-value problem formulation of the 2D finite element/boundary element (FE/BE) method is presented. >From this a posteriori error estimates and error indicators for the FE/BE method are developed and applied to electromagnetic scattering and radiation problems. The results obtained indicate that these error estimates and indicators can be obtained within negligible computational times and can be used successfully to obtain valuable a posteriori accuracy and convergence information regarding the reliability of the FE/BE method solutions. [Vol. 11, No. 2 (1996), pp 40-54]
Author(s): F.J.C. Meyer, D.B. Davidson, F.J.C. Meyer, D.B. Davidson
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
Download Link:Click here to download PDF     File Size: 1233 KB

Title: MODELLING OF AN ARBITRARILY-ORIENTED MOBILE TELEPHONE HANDSET IN THE FINITE-DIFFERENCE TIME-DOMAIN FIELD COMPUTATION METHOD
Abstract: The implementation of a generic mobile telephone handset model in the Finite Difference Time Domain (FDTD) method for computation of electromagnetic field distributions is described. The handset can be rotated about the principal FDTD axes to achieve any orientation. The 'thin wire' technique is used to model the antenna in a way that ensures that its correct electrical length is maintained despite the 'staircasing' effect of the FDTD grid. Computed predictions from the model agree with near-field measurements on a physical realisation of the handset, and accurate near and far fields are calculated for arbitrary orientations of the handset. It is concluded that this wire rotation technique has broad application to problems involving components that are required to move in relation to fixed structures. [Vol. 11, No. 2 (1996), pp 55-65]
Author(s): P.S. Excell, P. Olley, N.N. Jackson, P.S. Excell, P. Olley, N.N. Jackson
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
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Title: A MAGNETIC FIELD ITERATIVE TECHNIQUE FOR IMPROVING HIGH FREQUENCY PREDICTION METHODS
Abstract: A Magnetic Field Iterative Technique (MFIT) is developed as a technique for improving the results from high frequency based prediction methods. The technique combines the accuracy of low frequency methods with the speed of high frequency methods to develop a contraction mapping based, iterative solver, which is directly parallelizable on current massively parallel processing machines. In this paper, the MFIT is developed from a Magnetic Field Integral Equation (MFIE) and its contraction discussed. Results obtained mapping properties are using the technique and convergence properties are three dimensional perfect illustrations of the technique's presented for both two and electrically conducting (PEC) targets. [Vol. 11, No. 2 (1996), pp 66-71]
Author(s): Daniel D. Reuster, Gary A. Thiele, Paul W. Eloe, Daniel D. Reuster, Gary A. Thiele, Paul W. Eloe
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
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Title: MODELING OF REMOTE FIELD EDDY CURRENT TRANSIENT PHENOMENA
Abstract: An integral formulation is presented and used for the analysis of the Remote Field Eddy Current (RFEC) transient phenomena. The model presented allows simple and accurate modeling of RFEC systems in the presence of axisymmetric defects. The method has been validated first by comparison of the computed results with results obtained with an analytical model. Then the method was used to show that the Remote Field effect is mainly due to a direct induction effect rather than propagation effects. The Remote Field effect phenomena are usually analysed using a steady state domain. However, the results obtained here have shown that detection of defects is not due to a steady state phenomenon, but depends mainly on the transient signal. [Vol. 11, No. 2 (1996), pp 72- 75]
Author(s): M. Raugi, N. Ida, M. Raugi, N. Ida
File Type: Journal Paper
Issue:Volume: 11      Number: 2      Year: 1996
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Title: SOLUTION OF LAPLACE'S EQUATION USING MULTIPLE PATHS METHOD (MPM)
Abstract: A probabilistic method called the multiple paths method (MPM) is presented to solve the potential equation. Unlike other probabilistic techniques there is no need for the generation of a grid resulting in less computation time and simplicity. The method is based on the calculation of the probability of absorption of a particle at a point on the boundary. The random walk is along a "path" which is a line passing through the starting point, where the potential is to be determined. The results show good agreement with other probabilistic methods and numerical techniques. [Vol. 11, No. 3 (1996), pp 4-8
Author(s): J. Rashed-Mohasselel, M. Fasih, J. Rashed-Mohasselel, M. Fasih
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 349 KB

Title: A NEW DESIGN METHOD FOR LOW SIDELOBE LEVEL LOG-PERIODIC DIPOLE ANTENNAS
Abstract: A new design procedure for log-periodic dipole arrays is presented in this paper. In this method, either the scale factor or the number of dipole elements is selected, after the boom length, and the operating frequency region are specified. The procedure is applied iteratively, in conjunction to the Numerical Electromagnetic Code, to produce a design with low sidelobe levels. With this new procedure, the antenna designer has more control over the boom length; in older techniques, the boom length and the element spacing were dependent on previous calculations, which frequently resulted on unreasonable values Results for several designs are presented, showing the peak gain to peak-sidelobe level ratio, and the antenna gain as a function of frequency, for different scale factors and boom lengths, for a frequency range of 13 to 30 MHz. [Vol. 11, No. 3 (1996), pp 9-15]
Author(s): James K. Breakall, Rafael A. Rodriguez Solis, James K. Breakall, Rafael A. Rodriguez Solis
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 445 KB

Title: NUMERICAL EVALUATION OF SINGULAR INTEGRANDS IN THE APPLICATION OF THE CHARGE SIMULATION METHOD WITH DISTRIBUTED CHARGE DENSITY
Abstract: As it is well known the Charge Simulation Method is a numerical method for the computation of the electric field in three-dimensional problems, based on the concept of the substitution of the electrodic geometry with a series of elementary charge suitably arranged. In this paper we will show a possible, useful way to overpass the difficulties arising in the numerical computations on the integral expression of the electric potential in the contour points where the boundary conditions are imposed, when distributed surface charges are used in the simulation. The numerical approach presented here allows us to evaluate with accuracy the potential coefficients on the metallic surfaces, avoiding the presence of oscillatory numerical solutions in the computation of the electric potential and of the electric field strength around the electrodes, that generally occurs when discrete charges are used in the simulation. [Vol. 11, No. 3 (1996), pp 16-24]
Author(s): Ermanno Cardelli, Loris Faina, Ermanno Cardelli, Loris Faina
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 482 KB

Title: MEASURED RCS POLAR CONTOUR MAPS FOR CODE VALIDATION
Abstract: Measured radar cross-section (RCS) data as a function of the angle of incidence and of the frequency over a wide range provide an excellent basis for code validation. This paper examines the RCS of six targets measured as a function of the angle of incidence of the plane wave, and of the frequency, through and beyond the resonance range of target size. The RCS is presented as a function of frequency and incidence angle using a color contour map in a polar format, with the radius proportional to the frequency. Such polar contour maps exhibit striking patterns to the underlying scattering mechanisms and target geometry. The RCS as a function of incidence angle and frequency is available from the authors for an extensive collection of targets. [Vol. 11, No. 3 (1996), pp 25-43]
Author(s): C.L. Larose, C.W. Trueman, C.L. Larose, C.W. Trueman
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
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Title: AN EFFICIENT METHOD OF ANALYSIS OF CO-PLANAR DIPOLE ARRAY ANTENNAS
Abstract: Generalized impedance formulas for non-uniform array configurations based on the improved Circuit Theory (ICT) are presented for the first time in an English text. To further enhance the ICT as an accurate and fast method for evaluations, a new and more com pact closed-form formula is derived to replace a function requiring time intensive numerical integration during the implementation of the of the ICT algorithm in co-planar dipole array antenna evaluations. The resulting ICT computational scheme reduces the required CPU time by a factor of two and has the same order of accuracy as the conventional MoM. The new ICT implementation would be of considerable use as a Computer Aided Design (CAD) tool of co-planar dipole array antennas. [Vol. 11, No. 3 (1996), pp 44-54]
Author(s): A. I. Imoro, N. Inagaki, N. Kikuma, A. I. Imoro, N. Inagaki, N. Kikuma
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 848 KB

Title: AN ALGORITHM FOR SOLUTION OF THE INVERSE ELECTROMAGNETIC LIQUID METAL CONFINEMENT PROBLEM
Abstract: The design of an electromagnetic levitation system for large amounts of liquid metal requires the solution of an inverse field problem. The objective is to calculate the electromagnetic pressure distribution which corresponds to a specific metallo-static head. This paper describes an algorithm for the design of coil systems which will produce the desired pressure distribution. The technique is illustrated by the design of a torroidal levitation system. [Vol. 11, No. 3 (1996), pp 55-62]
Author(s): G.J. Bendzsak, G.J. Bendzsak
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 687 KB

Title: COMPARISON OF MAGNETICALLY INDUCED ELF FIELDS IN HUMANS COMPUTED BY FDTD AND SCALAR POTENTIAL FD CODES
Abstract: This paper presents a detailed numerical comparison of the magnetically-induced extremely low-frequency electric field and current density within an anatomically realistic model of the full human body, as computed using two different numerical techniques. The first technique is a recently-described full-wave quasi-static finite-difference time-domain (FDTD) method. The use of a time-ramped excitation involving pairs of oppositely-directed plane waves allows for the calculation of decoupled magnetic and electric induction in complex heterogeneous bodies, in relatively short (5 ns) simulation times. The second method is an implementation of Stevenson's method applied for isolated conducting bodies. With the lowest-order external magnetic field represented by a vector potential, the lowest-order internal electric field can be represented by a scalar conduction potential, and the magnetically-induced contribution can be calculated in isolation. Both methods have an underlying similarity in their finite-difference approach, but are nevertheless very distinct. Each code was used to calculate the fields, induced by three orthogonal uniform magnetic fields, in a 7.2 mm-resolution human full-body model. Three-dimensional correlation coefficients of better than 99.9998% were observed between current densities computed by the two methods. Individual edge electric fields typically agree to 3 significant digits. [Vol. 11, No. 3 (1996), pp 63-71]
Author(s): Trevor W. Dawson, Jan De Moerloose, Maria A. Stuchly, Trevor W. Dawson, Jan De Moerloose, Maria A. Stuchly
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 693 KB

Title: ANALYTIC VALIDATION OF A THREE-DIMENSIONAL SOLAR-POTENTIAL FINITE- DIFFERENCE CODE FOR LOW-FREQUENCY MAGNETIC INDUCTION
Abstract: This paper presents a detailed comparison of numerical and analytical calculations of the low-frequency electric and current density fields, induced by an applied uniform axial magnetic field, in an equatorially stratified sphere having the conductivity distribution Rho (_)=Rho0e- cos( _) with p {1,2} and > 0. As shown by the analytic solution, the resulting induced fields are fully three-dimensional, and the model therefore serves as a rigorous test of numerical codes The numerical method is a scalar-potential finite-difference scheme based on Stevenson's method for isolated conducting bodies. This computer code was recently shown to provide excellent agreement with results computed independently by a modified Finite-Difference Time-Domain method. Nevertheless, both codes share some underlying similarities, such as their common use of parallelepiped material voxels to represent the conductivity distribution, and of an edge-based staggered to model the electric fields. Therefore, it is of value to compare the numerical results with analytic ones The analytic model has a freely adjustable contrast parameter, and supports both pi and 2pi-periodic conductivity distributions. Numerical and analytical results are compared for several configurations. Full three-dimensional volumetric correlation coefficients are typically of the order of 99% or better. As might be expected, the main differences occur at the surface of the sphere, where the true circumferential fields are most poorly approximated by the staircasing approximation inherent the numerical approximation. [Vol. 11, No. 3 (1996), pp 72-81]
Author(s): Trevor W. Dawson, Maria A. Stuchly, Trevor W. Dawson, Maria A. Stuchly
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
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Title: THE GRADIENT ASSOCIATED CONJUGATE DIRECTION METHOD
Abstract: A new conjugate direction (CD) based method, GaCD by name, is addressed with its full derivations. Comparison with some commonly used CD methods is made, concluding that the GaCD method is among the best of them, in terms of an assessment number. A practical example is presented in which a waveguide-microstrip transition section is optimized with respect to its transmission parameter S2l. The measurement of the transition agrees very well with the numerical results. [Vol. 11, No. 3 (1996), pp 82-96]
Author(s): Min Zhang, Min Zhang
File Type: Journal Paper
Issue:Volume: 11      Number: 3      Year: 1996
Download Link:Click here to download PDF     File Size: 1873 KB

Title: THE NEC2 RADIATION PATTERNS OF UNDER-SEGMENTED WIRE GRID MODELS OF A FIGHTER AIRCRAFT COMPARED TO MEASUREMENTS
Abstract: This paper presents results of a NEC2 method of moments evaluation of VHF/UHF antennas on a wire grid model of a fighter aircraft. The study shows that practically useful radiation patterns results can be obtained when the grid model is considerably under-segmented in aircraft regions which are electrically far removed from the antennas. Normal modelling guide-lines requires approximately 35000 segments for the fighter grid model at 400 MHz; judicious under-segmentation gave useful results using a model comprising 5000 segments. This reduction in segments reduced computer time by a factor of 343 and memory requirements is reduced by a factor of 18. NEC2 radiation patterns are compared to measurements on a l/lOth scale model which was performed in an anechoic chamber compact range. [Vol. 10, No. 1 (1995), pp 5-14]
Author(s): 0. Givati, A.P.C. Fourie, 0. Givati, A.P.C. Fourie
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
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Title: A SURFACE INTEGRAL EQUATION FORMULATION FOR LOW CONTRAST SCATTERERS BASED ON RADIATION CURRENTS
Abstract: A new surface integral equation formulation based on radiation currents is presented. Numerical problems have been observed when treating low contrast scatterers with surface integral equation formulations based on the total equivalent currents. These problems result because the total equivalent currents are large compared with the radiation currents for low contrast materials. The surface integral equation formulation presented here avoids this problem by solving directly for the radiation currents. [Vol. 10, No. 1 (1995), pp 15-18]
Author(s): Paul M. Goggans, Allen W. Glisson, Paul M. Goggans, Allen W. Glisson
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
Download Link:Click here to download PDF     File Size: 423 KB

Title: THE MEASURED EQUATION OF INVARIANCE METHOD APPLIED TO RANDOMLY ROUGH SURFACES
Abstract: The Measured Equation of Invariance (MEI) method has received considerable attention recently. Unlike more traditional numerical techniques, MEI solutions are obtained by inversion of a relatively small and sparse matrix. Therefore, the MEI method can potentially provide a solution much more quickly than other techniques. To date, the MEI method has been applied primarily to discrete objects. In this paper, bistatic radar cross sections for one-dimensional, perfectly conducting, randomly rough surfaces are obtained using the MEI method. The implementation suitable for this problem requires some modification and enhancement of the original algorithm to achieve the desired accuracy. These algorithmic changes can be applied to the discrete scattering problem as well. Monte Carlo results for the bistatic scattering cross section for surfaces with Gaussian statistics and satisfying a Gaussian roughness spectrum are compared to those from another technique and excellent agreement is obtained. [Vol. 10, No. 1 (1995), pp 19-30]
Author(s): John B. Schneider, Shira Lynn Broschat, John B. Schneider, Shira Lynn Broschat
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
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Title: A GUIDE TO IMPLEMENTATIONAL ASPECTS OF THE SPATIAL DOMAIN INTEGRAL EQUATION ANALYSIS OF MICROSTRIP ANTENNAS
Abstract: In the analysis of microstrip radiating structures integral equation methods rate among the more accurate approaches. By far the most demanding part in the use of these methods is the actual numerical implementation. This paper presents a detailed illustrated description of the numerical implementation of a spatial domain mixed-potential integral equation analysis of microstrip radiating structures. [Vol. 10, No. 1 (1995), pp 40-51]
Author(s): Louis T. Hildebrand, Derek A. McNamara, Louis T. Hildebrand, Derek A. McNamara
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
Download Link:Click here to download PDF     File Size: 1533 KB

Title: PERFORMANCE OF A CHARACTERISTIC-BASED, 3-D, TIME-DOMAIN MAXWELL EQUATIONS SOLVER ON THE INTEL TOUCHSTONE DELTA
Abstract: A characteristic-based, windward numerical procedure for solving three-dimensional Maxwell equations in the time domain has been successfully ported to the Intel Touchstone Delta multicomputer. The numerical results by concurrent computation duplicated the earlier simulations of an oscillating electric dipole on a vector processor and compared well with the exact solutions. The parallelized code is scalable up to 512 nodes and incurs only up to 7.6% performance degradation. The sustained data processing rate is clocked at 6.551 Gigaops. However, the data I/O process is unscalable on the shared memory system. [Vol. 10, No. 1 (1995), pp 52-62]
Author(s): J. S. Shang, Kueichien C. Hill, Donald A. Calahan, J. S. Shang, Kueichien C. Hill, Donald A. Calahan
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
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Title: ON THE APPLICABILITY OF THE BICONJUGATE GRADIENT FFT METHOD FOR THE THIN CONDUCTING PLATE PROBLEM
Abstract: The application of the Biconjugate Gradient FFT method to the thin conducting plate problem is investigated. Upon comparing with a Conjugate Gradient FFT method, it is found that the Biconjugate Gradient solution requires a relatively larger error tolerance to achieve a comparatively well-behaved current distribution. Coupled with the requirement of only one matrix-vector product per iteration, the computational cost of the Biconjugate Gradient method is, thus, much smaller than those previously reported in the literature. Of particular importance is the use of the incident electric field as a starting estimate to alleviate the non-convergence behaviour which is usually associated with the application of a Biconjugate Gradient approach to conducting plates at grazing angle. For other angles of incidence, it is shown that this procedure also accelerates the resulting convergence rates as compared to those obtained by simply using zero as an initial estimate. [Vol. 10, No. 1 (1995), pp 63-68]
Author(s): T. V. TRAN, A. McCOWEN, T. V. TRAN, A. McCOWEN
File Type: Journal Paper
Issue:Volume: 10      Number: 1      Year: 1995
Download Link:Click here to download PDF     File Size: 702 KB

Title: REVISED INTEGRATION METHODS IN A GALERKIN BOR PROCEDURE
Abstract: Several relatively simple numerical changes improve the speed and accuracy of the early Mautz and Harrington discretization procedure for boundary element method calculations of scattering from axially symmetric bodies. This method is still in common use in programs such as CICERO and GRMBOR. For a fixed set of geometry points, changes in the azimuthal (o) integration reduce computer time, especially when lossy materials are involved. Changes in the integration along the generating curve (t) improve accuracy. The most interesting of these is the use of the equal area rule from parallel wire modeling of solid surfaces to answer the old question of the optimal constant for dealing with an integrable singularity in some of the t integrals. Some of these changes are applicable to a variety of integral equations and boundary conditions. Most of them can be implemented with little programming effort. Tests are shown for difficult cases involving spheres, and Mie series calculations are used for comparison. [Vol. 10, No. 2 (1995), pp 5-16]
Author(s): David R. Ingham, David R. Ingham
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
Download Link:Click here to download PDF     File Size: 886 KB

Title: HIGHER-ORDER FDTD METHODS FOR LARGE PROBLEMS
Abstract: The Finite-Difference Time-Domain (FDTD) algorithm provides a simple and efficient means of solving Maxwell's equations for a wide variety of problems. In Yee's uniform grid FDTD algorithm the derivatives in Maxwell's curl equations are replaced by central difference approximations. Unfortunately, numerical dispersion and grid anisotropy are inherent to FDTD methods. For large computational domains, e.g., ones that have at least one dimension forty wavelengths or larger, phase errors from dispersion and grid anisotropy in the Yee algorithm (YA) can be significant unless a small spatial discretization is used. For such problems, the amount of data that must be stored and calculated at each iteration can lead to prohibitive memory requirements and high computational cost. To decrease the expense of FDTD simulations for large scattering problems two higher-order methods have been derived and are reported here. One method is second-order in time and fourth-order in space (2-4); the other is second-order in time and sixth-order in space (2-6). Both methods decrease grid anisotropy and have less dispersion than the YA at a set discretization. Also, both permit a coarser discretization than the YA for a given error bound. To compare the accuracy of the YA and higher-order methods both transient and CW simulations have been performed at a set discretization. In general, it has been found that the higher-order methods are more accurate than the YA due to the reduced grid anisotropy and dispersion. However, the higher-order methods are not as accurate as the YA for the simulation of surface waves. This is attributed to the larger spatial stencil used in calculating the fields for the higher-order methods. More research is needed to examine the accuracy of higher-order methods at material boundaries. [Vol. 10, No. 2 (1995), pp 17-29]
Author(s): Charles W. Manry Jr, Shira L. Broschat, John B. Schneider, Charles W. Manry Jr, Shira L. Broschat, John B. Schneider
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
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Title: RADAR CROSS SECTION OF A RECTANGULAR CAVITY- A MASSIVELY PARALLEL CALCULATION
Abstract: A sequential code that calculates the radar cross section of a rectangular waveguide cavity was modified to execute on a MasPar MP-l massively parallel computer with a SIMD architecture. The code uses the mode matching method of analysis to produce a set of matrix equations. Steps taken to accomplish the parallelization are discussed and some specific examples of program modification are presented. Timing results for wideband data are given that demonstrate the power of parallel computers for this type of application. Suggestions are made for further improvements as increased memory space becomes available. [Vol. 10, No. 2 (1995), pp 30-45]
Author(s): L. D. Vann, L.T. Willet, J.S. Bagby, H.F. Helmken, L. D. Vann, L.T. Willet, J.S. Bagby, H.F. Helmken
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
Download Link:Click here to download PDF     File Size: 835 KB

Title: A NUMERICAL TECHNIQUE TO DETERMINE ANTENNA PHASE CENTER LOCATION FROM COMPUTED OR MEASURED PHASE DATA
Abstract: In many antenna applications, it is a requirement to have knowledge of the antenna phase center properties. Many interpretations of antenna phase center and its apparent location exist. This paper will present a formulation for determination of antenna phase center location derived using the antenna phase response. A fortran program, developed from the formulations, is used to calculate phase center location for several examples which include both computed and simulated measured phase data. A simple numerical technique is presented that processes measured phase data allowing accurate phase center determination. [Vol. 10, No. 2 (1995), pp 46-62]
Author(s): Steven R. Best, James M. Tranquilla, Steven R. Best, James M. Tranquilla
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
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Title: CONFORMAL ARRAY DESIGN SOFTWARE
Abstract: A powerful conformal array design computer program can be developed by modification of a physical optics based array fed reflector analysis computer program. [Vol. 10, No. 2 (1995), pp 63-74]
Author(s): H.K. Schuman, H.K. Schuman
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
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Title: COMPARISON OF THE INPUT IMPEDANCE OF MONOPOLE ANTENNAS OBTAINED BY NEC, MINlNEC, AND MEASUREMENTS
Abstract: This paper compares the input impedance of monopole antennas numerically calculated by NEC and MININEC with experimental results. This comparison determines the limitation of these two computer codes used for modeling more complicated structures. Two groups of monopoles are considered. The first group consists of eight electrically thin monopoles of length .28 meters (.235 wavelengths at 252 MHz) and radii of .4064, . 7874, 1.168, 1.562, 2.390, 3.162, 6.350, and 7.920 millimeters (.341E-3, .661E-3, .981E-3, 1.31E-3, 2.01E-3, 2.66E-3, 5.33E-3, and 6.65E-3 wavelengths at 252 MHz). For this group, impedance calculations were compared to measurements over the band of 237-267 MHz. The second group consists of five electrically thick monopoles of length .2 wavelengths and radii of .0509, .0635, .0847, .1129, and .1270 wavelengths. For the second group impedance calculations were compared with measurements of tubular monopoles with flat ends. The results of this paper show that the extended kernel option of NEC predicted measured monopole impedance measurements more accurately than MININEC. [Vol. 10, No. 2 (1995), pp 75-85]
Author(s): R. J. Bauerle, J. K. Breakall, R. J. Bauerle, J. K. Breakall
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
Download Link:Click here to download PDF     File Size: 745 KB

Title: ACCURATE MODELING OF STEPPED-RADII ANTENNAS
Abstract: The LP8, eight element, log periodic antenna made by M2 Enterprises has recently been modeled at Penn State University using both Version 2 and 4 of the Numerical Electromagnetics Code (NEC). The antenna has a steppedradii element construction and operates from 10 to 30 MHz. The stepped-radii element construction is difficult to model using NEC Version 2. To model a stepped-radii antenna with this version, equivalent lengths of constant radii are calculated using another method of moments program called ELNEC. These equivalent lengths replaced the original stepped radii elements of the log periodic antenna during the modeling. Fortunately, NEC Version 4 can simulate the stepped-radii elements directly, which makes the modeling procedure much easier and accurate. Both NEC models show good agreement with the measurements when compared to VSWR measurements. The authors hope that this paper will help others with similar modeling problems who cannot yet obtain NEC Version 4. [Vol. 10, No. 2 (1995), pp 86-95]
Author(s): A. I. Bauerle, J. K. Breakall, A. I. Bauerle, J. K. Breakall
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
Download Link:Click here to download PDF     File Size: 726 KB

Title: MUTUAL VALIDATION OF THREE PROGRAMS FOR NUMERIC ANTENNA COMPUTATIONS
Abstract: The numerical results obtained by three different codes, GALNEC, WARAN and NEC-2 are compared for thin dipoles and thick ones with hemispherical end caps and for arrays of such collinear dipoles. The electric field integral equation and Galerkin's method are used in the code GALNEC where solid thick dipole bodies are implemented. Mei's (1965) integral equation and collocation technique are wed in the code WARAN, where thick dipoles are simulated as arrays of thin wires. Good agreement has been obtained for current distri- butions and input and mutual impedances. [Vol. 10, No. 2 (1995), pp 96-101]
Author(s): Andrew A. Efanov, Harald Schopf, Bernhard Schnizer, Andrew A. Efanov, Harald Schopf, Bernhard Schnizer
File Type: Journal Paper
Issue:Volume: 10      Number: 2      Year: 1995
Download Link:Click here to download PDF     File Size: 421 KB

Title: Using GPUs for Accelerating Electromagnetic Simulations
Abstract: The computational power and memory bandwidth of graphics processing units (GPUs) have turned them into attractive platforms for general-purpose applications at significant speed gains versus their CPU counterparts [1]. In addition, an increasing number of today's state-ofthe- art supercomputers include commodity GPUs to bring us unprecedented levels of performance in terms of raw GFLOPS and GFLOPS/cost. Inspired by the latest trends and developments in GPUs, we propose a new paradigm for implementing on GPUs some of the major aspects of electromagnetic simulations, a domain traditionally used as a benchmark to run codes in some of the most expensive and powerful supercomputers worldwide. After reviewing related achievements and ongoing projects, we provide a guideline to exploit SIMD parallelism and high memory bandwidth using the CUDA programming model and hardware architecture offered by Nvidia graphics cards at an affordable cost. As a result, performance gains of several orders of magnitude can be attained versus threadlevel methods like pthreads used to run those simulations on emerging multicore architectures
Author(s): M. Ujaldon
File Type: Journal Paper
Issue:Volume: 25      Number: 4      Year: 2010
Download Link:Click here to download PDF     File Size: 309 KB

Title: Unconditionally Stable Locally One-Dimensional FDTD Methods for Efficient Electromagnetic Simulations
File Type: Conference Paper
Issue:Volume: Optoelectronic modeling      Number:      Year: 2009
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Title: Tuning Space Mapping for Microwave Design Optimization
File Type: Conference Paper
Issue:Volume: Electromagnetic Simulations using Sonnet      Number:      Year: 2011
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Title: Time Domain Modeling of Active Materials
File Type: Conference Paper
Issue:Volume: S48 Computational Nanophotonics: Advanced Numerical Methods and Applications II      Number:      Year: 2018
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Title: The Way from Natural to Artificial
File Type: Conference Paper
Issue:Volume: 2-1-C Properties, Modelling and Novel Concepts of Artificial Electromagnetic Structures I      Number:      Year: 2017
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Title: The Validationof EM Modelling Codes. A User Viewpoint
Abstract: Computer codes for solving radiation and scattering problems have becomed powerful and widely available. The user of such a code must initially convince himself that his copy of the code executes correctly on his specific computer with his particular compiler. He must then build up expertise in constructing models for solution by the code which obey the restrictions imposed by the "modelling guildelines" accompanying the code in a user's manual. Users often want to solve "real" problems that do not conform to the problem geometry envisaged by the code writer. The user replaces the "real" structure with a computer model solvable by the code, and which obeys the modelling guidelines. The user must then carry out a "model validation" in which the computer model is tested against full-scale or scale model measurements. A successful "model validation" contributes to the user community's "experience base" and lends confidence to both the computer code and to the modelling process. Sometimes an unsuccessful attempt at modeling exposes a genuine limitation of the code. Then a new "modelling guideline" can be formulated to aid other users in avoiding the same difficulties. This paper reviews code development to highlight the origin of "modelling guidelines", and how they are extended by the user community. From the user's point of view, the "experience base" is augmented whenever a successful "model validation" is carried out and reported. Several examples are presented of the difficulties that may be encountered in computer modelling, and how such difficulties lead to further "modelling guidelines" aimed at aiding others in solving similar problems.
Author(s): S.J. Kubina, C.W. Trueman, S.J. Kubina, C.W. Trueman
File Type: Journal Paper
Issue:Volume: 4      Number: 3      Year: 1989
Download Link:Click here to download PDF     File Size: 731 KB

Title: The Success of GPU Computing in Applied Electromagnetics
Abstract: In the field of electromagnetic modeling, whether it is the complex designs for engineered materials or devices and components integrated within their natural environments, there is a big drive for highly efficient numerical techniques to model the performance of complex structures. This often cannot be achieved by conventional computer systems, but rather through using the so-called high performance computing (HPC) systems that utilize hardware acceleration. We review recent General Purpose Graphics Processing Units (GPGPU) computing strategies introduced in four fields of computational electromagnetics: Finite-Difference Time-Domain (FDTD), Finite Elements Method (FEM), Method of Moments (MoM) and ElectroMagnetic Ray Tracing (EMRT).
Author(s): A. Capozzoli, O. Kilic, C. Curcio, A. Liseno
File Type: Express Journal Paper
Issue:Volume: 1      Number: 4      Year: 2016
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Title: The Success of GPU Computing in Applied Electromagnetics
Abstract: In the field of electromagnetic modeling, whether it is the complex designs for engineered materials or devices and components integrated within their natural environments, there is a big drive for highly efficient numerical techniques to model the performance of complex structures. This often cannot be achieved by conventional computer systems, but rather through using the so-called high performance computing (HPC) systems that utilize hardware acceleration. We review recent General Purpose Graphics Processing Units (GPGPU) computing strategies introduced in four fields of computational electromagnetics: Finite-Difference Time-Domain (FDTD), Finite Elements Method (FEM), Method of Moments (MoM) and ElectroMagnetic Ray Tracing (EMRT).
Author(s): A. Capozzoli, O. Kilic, C. Curcio, A. Liseno
File Type: Journal Paper
Issue:Volume: 33      Number: 2      Year: 2018
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Title: The Success of GPU Computing in Applied Electromagnetics
Abstract: In the field of electromagnetic modeling, whether it is the complex designs for engineered materials or devices and components integrated within their natural environments, there is a big drive for highly efficient numerical techniques to model the performance of complex structures. This often cannot be achieved by conventional computer systems, but rather through using the so-called high performance computing (HPC) systems that utilize hardware acceleration. We review recent General Purpose Graphics Processing Units (GPGPU) computing strategies introduced in four fields of computational electromagnetics: Finite-Difference Time-Domain (FDTD), Finite Elements Method (FEM), Method of Moments (MoM) and ElectroMagnetic Ray Tracing (EMRT).
Author(s): A. Capozzoli, O. Kilic, C. Curcio, A. Liseno
File Type: Express Journal Paper
Issue:Volume: 33      Number: 2      Year: 2018
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Title: The Locally-corrected Nystrom Method: Progress and Challenges
File Type: Conference Paper
Issue:Volume: S05 Locally Corrected Nystrom Method and its Applications      Number:      Year: 2021
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Title: THE COMPUTATION OF LINEAR DISPERSIVE ELECTROMAGNETIC WAVES
Abstract: Numerical solutions of the equations describing electromagnetic pulse propagation in geometrically complex Debye-dispersive dielectrics are used in the development of safety standards for human exposure to non-ionizing radiation. Debye dispersion is a relaxation process, a phenomenon which occurs when the underlying material is forced into non-equilibrium due to the passing waves. This relaxation is typically stiff in applications, and the system of equations is then singularly perturbed. Such systems are notoriously expensive to solve with standard numerical methods. We review previous work related to the numerical solution of such problems, and consider a representative numerical scheme in order to elucidate the nature of the challenge posed to Computational Electromagnetics by the stiffness. Further. an analysis of the stiffness leads us to propose a scheme that seems "natural" for the problem at hand. [Vol. 11, No. 1 (1996), pp 8-16, Special issue on Applied Mathematics: Meeting the challenges presented by computational electromagnetics]
Author(s): Peter G. Petropoulos, Peter G. Petropoulos
File Type: Journal Paper
Issue:Volume: 11      Number: 1      Year: 1996
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Title: Teaching Electromagnetics via Virtual Tools and a New Electromagnetic Engineering Program (EMEP)
File Type: Conference Paper
Issue:Volume: CEM for EM Education      Number:      Year: 2010
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Title: Spoof Surface Plasmons for Guiding and Radiating Electromagnetic Waves
File Type: Conference Paper
Issue:Volume: 6-ME-1 Advanced Plate Antenna and Array Technologies II      Number:      Year: 2018
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Title: Simulation and Optimization of Photonic Crystal Structures
File Type: Conference Paper
Issue:Volume: Computational Electromagnetics for Photonics      Number:      Year: 2007
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Title: Self-adjoint S-parameter Sensitivities for TLM problems
File Type: Conference Paper
Issue:Volume: Advances in Computer-Aided Design of Electromagnetic Structures and Devices      Number:      Year: 2006
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Title: Scalability of Hybrid Full Wave/Asymptotic EM Solver Techniques for Naval Antennas
File Type: Conference Paper
Issue:Volume: S32 Recent Advances in Asymptotic Methods      Number:      Year: 2021
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Title: Review of the Latest Feature Additions to the Electromagnetic Solver FEKO
File Type: Conference Paper
Issue:Volume: S44 EM Modeling Using FEKO I      Number:      Year: 2016
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Title: Review of Six-Port Interferometer Technology
File Type: Conference Paper
Issue:Volume: Six Port Technology in Software Radio Wireless Communication Systems      Number:      Year: 2007
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Title: Review of SIW Power Capacity and Verification on Multi-Physics Simulation
File Type: Conference Paper
Issue:Volume: 6-ME-3 Multi-physics Simulation of Coupled Field-Circuit Problems      Number:      Year: 2018
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Title: Review of Selected New Features in FEKO 2018
File Type: Conference Paper
Issue:Volume: S23 EM Modeling Using FEKO I      Number:      Year: 2018
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Title: Review of RF Cloaking Techniques for Antenna Applications
Abstract: This paper reviews the background phenomenon of various cloaking techniques such as transformation optics, transmission line network, microwave network cloak, scattering cancellation techniques in the applications of antenna field particularly in hiding the obstacle from the electromagnetic source and reducing the mutual coupling between two antennas that was placed closed to each other. Cloaking at multiple frequencies in each cloaking techniques are also compared. The comparative study showed that the scattering cancellation technique based on aperiodic Frequency Selective Surfaces (FSS) structure will dominate the electromagnetic cloaking field in near future.
Author(s): N. Kumutha, K. Hariharan, N. Amutha, B. Manimegalai
File Type: Journal Paper
Issue:Volume: 33      Number: 8      Year: 2018
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Title: Review of Recent Advances and Future Challenges in Antenna Measurement
Abstract: This paper reviews the last advances in Antenna Measurement Field that took place during the previous years in order to analyse the challenges for the antenna measurement community, both industrial and academic, for the future years. The paper begins with an introductory review of the antenna measurement methodologies innovations, continuing with measurement systems technical improvements and concluding with the challenges for the antenna measurement community in the close future.
Author(s): M. Sierra-Castañer
File Type: Express Journal Paper
Issue:Volume: 1      Number: 2      Year: 2016
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Title: Review of Recent Advances and Future Challenges in Antenna Measurement
Abstract: This paper reviews the last advances in Antenna Measurement Field that took place during the previous years in order to analyse the challenges for the antenna measurement community, both industrial and academic, for the future years. The paper begins with an introductory review of the antenna measurement methodologies innovations, continuing with measurement systems technical improvements and concluding with the challenges for the antenna measurement community in the close future.
Author(s): M. Sierra-Castañer
File Type: Express Journal Paper
Issue:Volume: 33      Number: 1      Year: 2018
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Title: Review of Recent Advances and Future Challenges in Antenna Measurement
Abstract: This paper reviews the last advances in Antenna Measurement Field that took place during the previous years in order to analyse the challenges for the antenna measurement community, both industrial and academic, for the future years. The paper begins with an introductory review of the antenna measurement methodologies innovations, continuing with measurement systems technical improvements and concluding with the challenges for the antenna measurement community in the close future.
Author(s): M. Sierra-Castañer
File Type: Journal Paper
Issue:Volume: 33      Number: 1      Year: 2018
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Title: Review of Complex Looped FDTD and its new applications
File Type: Conference Paper
Issue:Volume: Modeling Techniques for Periodic Structures and Metamaterial Applications - I      Number:      Year: 2008
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Title: Review of Advanced EM Modeling Techniques in the Computer Code FEKO
File Type: Newsletter Paper
Issue:Volume: 18      Number: 2      Year: 2003
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Title: Review -- Grid Computing for Electromagnetics
File Type: Newsletter Paper
Issue:Volume: 20      Number: 1      Year: 2005
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Title: Retrospect of Space Solar Power Stations History
File Type: Conference Paper
Issue:Volume: 8-TP-4 In Celebration of 70th Birthday of Prof. Jia-dong Xu II      Number:      Year: 2018
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Title: Retrospect of Space Solar Power Stations History
File Type: Conference Paper
Issue:Volume: 10-TE-4 In Celebration of 70th Birthday of Prof. Jia-dong Xu III      Number:      Year: 2018
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Title: Response Correction Techniques for Microwave Design Optimization
File Type: Conference Paper
Issue:Volume: Electromagnetic-Simulation-Driven-Design: Modeling and Optimization      Number:      Year: 2011
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Title: Reconfigurable Origami Antennas
File Type: Conference Paper
Issue:Volume: S42 Physically Reconfigurable Antennas and Arrays: Design, Modeling and Materials I      Number:      Year: 2019
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Title: Recent Advances in Sensitivity Analysis with Frequency-Domain Full-Wave EM Solvers
Abstract: This paper introduces recent developments in efficient sensitivity analysis with numerical electromagnetic solvers in the frequency domain. We start by reviewing our original discrete approaches for sensitivity analysis. We then propose and investigate, for the first time, two new discrete approaches which enhance the accuracy of the estimated derivatives. All four introduced approaches are based on the adjointvariable method and target solvers on structured grids. Discussion and comparison of the accuracy and convergence for the different approaches are also given. Examples include waveguide and printed structures.
Author(s): S. M. Ali, N. K. Nikolova, M. H. Bakr, S. M. Ali, N. K. Nikolova, M. H. Bakr
File Type: Journal Paper
Issue:Volume: 19      Number: 3      Year: 2004
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Title: RAY-TRACING TECHNIQUES FOR MOBILE COMMUNICATIONS
Abstract: In this paper an application for mobile communication of several ray-tracing techniques is presented. The techniques work in combination with deterministic propagation models based on GTD/UTD techniques. Several ray-tracing techniques are reviewed and some results applying one of them, the Angular Zeta Buffer (AZB) method for urban and indoor scenarios are shown, obtaining in all the cases good results comparing with measurements.
Author(s): O. Gutierrez, F. Saez de Adana, I. Gonzalez, J. Perez, M. E. Cetedra, O. Gutierrez, F. Saez de Adana, I. Gonzalez, J. Perez, M. E. Cetedra
File Type: Journal Paper
Issue:Volume: 15      Number: 3      Year: 2000
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Title: Ray-Launching Geometrical Optics in FEKO: A Summary of the Last Four Years of Intensive Development
File Type: Conference Paper
Issue:Volume: 10-TE-3 Recent Advances on Electromagnetics Modeling and Simulation Techniques II      Number:      Year: 2018
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Title: Radar cross section of exhaust ions in HF region
File Type: Conference Paper
Issue:Volume: High Frequency Techniques      Number:      Year: 2012
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Title: Progress on Microwave Devices Fabricated Using Stereolithography 3-D Printing Technique
File Type: Conference Paper
Issue:Volume: 2-3-C Advanced Manufacturing Technologies for Microwave Devices      Number:      Year: 2017
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Title: Progress of Tensor-Based High-Dimensional Uncertainty Quantification of Process Variations
File Type: Conference Paper
Issue:Volume: S05 Locally Corrected Nystrom Method and its Applications      Number:      Year: 2021
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Title: Progress and Future Work on the NS-FDTD Method
File Type: Conference Paper
Issue:Volume: Finite Difference Methods      Number:      Year: 2013
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Title: Physics-Based Aggregate-Functions Approaches to Large Mom Problems
Abstract: Aggregate functions approaches construct efficient MoM basis functions by suitably grouping standard (e.g. Rao-Wilton- Glisson) functions. The application domains, objectives and related means of achieving them can be significantly different. In this paper we review some recent advances in aggregatefunctions methods, putting them in a unifying perspective. We address matrix compression, multi-resolution sets, low- and high-frequency constructs. They can reduce the degrees of freedom of the problem so as to allow a direct, iteration-free solution, or can accelerate the convergence rate of iterative methods. We analyze compressive methods in more detail, providing general discussion and specific implementation examples.
Author(s): L. Matekovits, G. Vecchi, F. Vico
File Type: Journal Paper
Issue:Volume: 24      Number: 2      Year: 2009
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Title: PARALLEL MATRIX SOLVERS FOR MOMENT METHOD CODES FOR MIMD COMPUTERS
Abstract: Parallel algorithms are presented that are suitable for the solution of the system of linear equations generated by moment method problems on local memory Multiple Instruction, Multiple Data (MIMD) parallel computers. The two most widely used matrix solution algorithms in moment method codes are described, namely the conjugate gradient (CG) method and LU decomposition. The underlying philosophy of parallelism is briefly reviewed. Suitable parallel algorithms are then described, presented in pseudo-code, their timing behaviour analyzed the- oretically, and timing results measured on a particular MIMD computer- -a transputer array --are presented and compared to the theoretical timing models. It is concluded that efficient parallel algorithms for both the CG and LU exist and that MIMD computers offer an attractive computational platform for the solution of moment method problems with large numbers of unknowns. [Vol. 8, No. 2 (1993), pp 144-175]
Author(s): David B. Davidson, David B. Davidson
File Type: Journal Paper
Issue:Volume: 8      Number: 2      Year: 1993
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Title: PARALLEL COMPUTATION OF LARGE-SCALE ELECTROMAGNETIC FIELD DISTRIBUTIONS
Abstract: Some experience of the use of high-frequency electromagnetics software on parallel computers is reported. Types of such computers are reviewed and approaches to the parallelisation of existing serial software are discussed. A practical large-scale problem is presented involving the modelling in very fine detail of electromagnetic penetration into biological systems. This was tested on state-of-the-art parallel computers and important practical and strategic aspects of the experience derived are discussed. It was found that considerable programmer effort was required to optimise the software to use the computer architecture effectively, but that efficient acceleration of the run-times of typical computational tasks could be achieved, provided that the tasks were large and were partitioned optimally.
Author(s): Peter S. Excell, Adam D. Tinniswood, Kathleen Haigh-Hutchinson, Peter S. Excell, Adam D. Tinniswood, Kathleen Haigh-Hutchinson
File Type: Journal Paper
Issue:Volume: 13      Number: 2      Year: 1998
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Title: Overview of Mesh Truncation Algorithms in PDEs for Maxwell Equations
File Type: Conference Paper
Issue:Volume: In Tribute To Dr. Zoltan Cendes      Number:      Year: 2012
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Title: Overview of Inverse Scattering, Imaging, and Parallel Computing
File Type: Conference Paper
Issue:Volume: Efficient Numerical Solutions of Large Multi-dimensional Inverse Scattering Problems      Number:      Year: 2007
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Title: Optimizing the Parallel Implementation of a Finite Difference Time Domain Code on a Multi-user Network of Workstations
Abstract: The implementation of a parallel, three dimensional, finite difference time domain (FDTD) computer program is considered and applied to a test scattering problem on a multi-user network of desktop workstations. The computation has primarily been done on a local area network (LAN) using six identical HP 9000/715 workstations (i.e. a homogeneous environment) with the Parallel Virtual Machine (PVM) software being employed as the communications harness.In this paper the sequential and parallel FDTD approaches are reviewed. We investigate the factors which cause a reduction in efficiency in the latter, such as host allocation and load balancing. We propose a task migration process, which is efficient for the FDTD algorithm, as a partial solution. The advantages of this approach are discussed and further developments based on available computational resources are suggested
Author(s): J. V. Mullan, C. J. Gillan, V. F. Fusco, J. V. Mullan, C. J. Gillan, V. F. Fusco
File Type: Journal Paper
Issue:Volume: 13      Number: 2      Year: 1998
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Title: Optimizing Multiple GPU FDTD Simulations in CUDA
File Type: Conference Paper
Issue:Volume: Parallel and Hardware Acceleration for Computational Electromagnetics      Number:      Year: 2011
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Title: On the numerical modeling of graphene and silicene for EM solvers
File Type: Conference Paper
Issue:Volume: Computational Methods in Nanoelectromagnetics      Number:      Year: 2014
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Title: On the Discretization of Fredholm Integral Equations of First Kind Using Compactly Supported Wavelets
File Type: Conference Paper
Issue:Volume: Advances in Integral Equation Techniques      Number:      Year: 2003
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Title: Numerical Validation of a Boundary Element Method with Electric Field and Its Normal Derivative as the Boundary Unknowns
Abstract: We recently developed a surface integral equation method where the electric field and its normal derivative are chosen as the boundary unknowns. After reviewing this formulation, we present preliminary numerical calculations that show good agreement with the known results. These calculations are encouraging and invite the further development of the numerical solution.
Author(s): J. Markkanen, A. J. Yuffa, J. A. Gordon
File Type: Journal Paper
Issue:Volume: 34      Number: 2      Year: 2019
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Title: Numerical Validation of a Boundary Element Method With E and @E @N as the Boundary Unknowns
File Type: Conference Paper
Issue:Volume: S28 Computational Methods for Complex EM Domains, Integral Equation Methods      Number:      Year: 2018
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Title: Numerical Simulation Approaches for Phased Array Design
Abstract: Abstract - This paper reviews the two well-known numerical simulation techniques that are widely used in antenna modeling; the finite-difference time-domain (FDTD) and the Method of Moments (MoM). The packages FDANT (prepared in Fortran language by using FDTD) and NEC2 (public domain code for the MoM) are used to model various types of antenna arrays, their advantages/disadvantages are discussed on characteristic design examples, and they are calibrated one against the other. Also, a simple Matlab package (ANTEN_GUI) for the visualization of radiation patterns, beam forming and beam steering capabilities of user-designed planar arrays of isotropic radiators (which can be used to test the above mentioned packages and as an educational tool, in e.g., antennas and propagation lectures) is introduced1.
Author(s): L. Sevgi, L. Sevgi
File Type: Journal Paper
Issue:Volume: 21      Number: 3      Year: 2006
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Title: Neural Network Based Methods for Nonlinear Behavioral Modeling of RF and Microwave Circuits
File Type: Conference Paper
Issue:Volume: Microwave Modeling and CAD      Number:      Year: 2009
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Title: Near-field RCS Measurement and Microwave Imaging Diagnosis-A Review of NWPU Work
File Type: Conference Paper
Issue:Volume: 9-P-2 Poster      Number:      Year: 2018
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Title: Multiple Beam Antenna Technology for Satellite Communications Payloads
Abstract: Abstract—This paper reviews multiple beam antenna (MBA) technologies that are applicable for satellite communications payloads. It provides design, performance analysis, and hardware implementation aspects of various types of MBAs that include reflector MBAs, phased array MBAs, and lens MBAs. Parametric design of these MBAs and RF analysis for coverage gain and inter-beam isolation are given. Recent advances and trends in MBA technologies for space applications are discussed.
Author(s): S. Rao, M. Tang, C. Hsu, S. Rao, M. Tang, C. Hsu
File Type: Journal Paper
Issue:Volume: 21      Number: 3      Year: 2006
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Title: Multi-Layer LCP Technology for Millimetre Wave Applications
File Type: Conference Paper
Issue:Volume: System-on-Package (SoP) Wireless Components      Number:      Year: 2011
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Title: Modeling and Analysis of a Dual-Band Dual-Polarization Radiator Using FEKO
Abstract: A dual-band hybrid antenna element comprising of microstrip and waveguide radiating elements is theoretically investigated through computer simulations. The low band radiator is a Shorted Annular Ring (SAR) microstrip antenna and the high band antenna is an open ended circular waveguide. First, the characteristics of a SAR patch antenna are presented and reviewed. Then the dual-band antenna configuration is described, which is realized by forming a waveguide radiator in the shorted region of the SAR microstrip antenna. Modeling and analysis of the SAR patch antenna and the hybrid element are investigated using the method-of-moment-based software package FEKO. The analysis includes return loss computations showing the element bandwidth at different frequency bands and the radiation patterns in the E- and H- planes. Feeding the element in phase quadrature produces circular polarizations (CP). The radiation patterns of the CP dual-band element are also analyzed using FEKO and the axial ratio performance is subsequently assessed
Author(s): Amir I. Zaghloul, C. Babu Ravipati, M. T. Kawser, Amir I. Zaghloul, C. Babu Ravipati, M. T. Kawser
File Type: Journal Paper
Issue:Volume: 22      Number: 1      Year: 2007
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Title: Metamaterial Enhanced Antenna Systems: A Review
File Type: Conference Paper
Issue:Volume: S08 Design, Analysis and Applications of EM Metasurfaces I      Number:      Year: 2018
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Title: MERCURY MOM: An Applied RWG EM Scattering Code for Electrically Large Bodies
File Type: Conference Paper
Issue:Volume: 30 Years of RWG Basis Functions      Number:      Year: 2011
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Title: Inverse Scattering and Information Management – Trends and Envisaged Strategies
File Type: Conference Paper
Issue:Volume: 4-MP-5 Inverse Scattering - Theory, Methods and Applications I      Number:      Year: 2018
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Title: Introduction to Genetic Algorithms in Electromagnetics
Abstract: This special issue of the ACES Journal is devoted to nev developments in Genetic Algorithm (GA) applications in computational electromagnetics. Genetic Algorithms have become extremely popular in the computational electromagnetics literature. The papers included in this special issue are very arcane, so I decided to include an unreviewed tutorial overview at the last minute as an introduction for those of you who are at a more basic level. GAs model natural selection and genetics on a computer to optimize a wide range of problems.
Author(s): Randy L. Haupt, Randy L. Haupt
File Type: Journal Paper
Issue:Volume: 15      Number: 2      Year: 2000
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Title: Higher-order (LT/QN) vector finite elements for waveguide analysis
Abstract: The finite element (FE) formulation for waveguide discontinuity analysis is reviewed and extended to multiple, arbitrarily-oriented ports. Several higher-order vector elements - specifically hierarchal linear tangential/quadratic normal (LT/QN) - are compared, and the extensions required to incorporate LT/QN elements in the formulation are presented. The improved accuracy afforded by LT/QN elements compared to constant tangential/linear normal (CT/LN) elements is investigated by considering energy conservation in an empty waveguide. Results obtained using both CT/LN and LT/QN elements are also shown for a problem of engineering interest: an E-plane bend. Results for the LT/QN elements compare especially well to approximate analytical results using quite coarse meshes. The paper concludes with a discussion of the use of iterative solvers and possible convergence problems encountered when using higher-order elements.
Author(s): David B Davidson, David B Davidson
File Type: Journal Paper
Issue:Volume: 17      Number: 1      Year: 2002
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Title: Genetic Algorithm Applications for Phased Arrays
Abstract: Abstract—Analytical approaches to phased array optimization started in the mid 1940s and transitioned to numerical techniques that can find a local minimum. Computers spurred the development of many different local optimization algorithms that worked well for a few variables and a cost function with a single minimum. In the 1990s, the genetic algorithm (GA) emerged as a competent optimization algorithm for a wide range of complex cost functions. This paper reviews phased array optimization and lays the foundation for the use of the GA. An extensive reference list is provided and some future research areas are discussed.
Author(s): R. L. Haupt, R. L. Haupt
File Type: Journal Paper
Issue:Volume: 21      Number: 3      Year: 2006
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Title: GA-MoM Optimization of Slot Arrays
File Type: Conference Paper
Issue:Volume: S33 Electromagnetic Simulation for RF and Microwave Design Optimization      Number:      Year: 2018
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Title: Fundamental Limitations on the Use of Open-Region Boundary Conditions and Matched Layers to Solve the Problem of Gratings in Metallic Screens
Abstract: Interest in accurate modeling of the electromagnetic wave scattering from grating surfaces has been renewed due to recent advances in the manipulation and localization of the light in novel application of plasmonic resonance. This work briefly reviews the frequency-domain finite methods that have been used extensively to solve the grating problem. Emphasis will be placed on the finite methods that use local boundary operators or matched layers to truncate the computational boundary. It is shown that significant errors can be generated when using either of these two mesh truncation techniques even if the truncation boundaries are receded to avoid any evanescent waves emanating from the gratings. To quantify the error, the solutions obtained using the boundary condition or matched layers are compared to the solutions obtained using either mode matching or the surface integral equation method, both of which are devoid of truncation boundary related approximations and errors. Additionally, limitations on the use of the periodic boundary condition to truncate the mesh for periodic problems are also addressed.
Author(s): B. Alavikia, O. M. Ramahi
File Type: Journal Paper
Issue:Volume: 25      Number: 8      Year: 2010
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Title: Flammer’s Exact Solution for the Circular Conducting Disk: A Benchmark Problem for EM Software Validation
File Type: Conference Paper
Issue:Volume: S03 Computational Electromagnetics, Advanced Algorithms and Emerging Applications      Number:      Year: 2018
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Title: FINITE ELEMENTS IN ELECTROMAGNETICS: A JUBILEE REVIEW
Abstract: This review describes the historical origins and the present state of the finite element method in electromagnetics. The foundation principles of finite elements are briefly reviewed. Applications are mainly to two and three dimensional problems of microwave and optical structures. The major types of scalar element are noted, and edge-interpolative vector elements are reviewed, firstly for the waveguide problem and then in three dimensions. An extensive bibliography is given, particularly stressing review papers. [Vol. 9, No. 2 (1994), Special Issue on The Numerical Computation of Low Frequency Electromagnetic Fields, pp 10-24]
Author(s): J. Brian Davies, Peter P. Silvester, J. Brian Davies, Peter P. Silvester
File Type: Journal Paper
Issue:Volume: 9      Number: 2      Year: 1994
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Title: FDTD Modeling of Electromagnetic and Thermal Dosimetry in Human for Microwave Exposures
File Type: Conference Paper
Issue:Volume: Advances in Finite Difference Time Domain      Number:      Year: 2009
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Title: EVOLUTION OF A SUITE OF COMPUTATIONAL MODELING TOOLS FOR MOBILE TELEPHONE DOSIMETRY STUDIES AT THE UNIVERSITY OF BRADFORD, U.K.
Abstract: The evolution of a set of software and skills for the computational simulation of the interaction of mobile telephones with the human body is reviewed. These have been developed and applied in the authors' research group over the past decade. The work has aimed at maximization of realism in the representation of the body components and the telephone through use of MRI images, use of resolutions down to 1mm, incorporation of a hand into the model, development of a rotation algorithm for the telephone, development of techniques for modeling helical antennas, and development of hybrid techniques to allow the Method of Moments to be used to model the telephone, combined with finite difference methods for the human tissues. Generic experience and specimen results are presented. It is argued that the policy of pursuing realism in the simulation, beyond the level that is sufficient on physical grounds, is essential to convince the non-specialist public of the trustworthiness of the work.
Author(s): Peter S. Excell, John A. Vaul, Peter S. Excell, John A. Vaul
File Type: Journal Paper
Issue:Volume: 16      Number: 2      Year: 2001
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Title: Estimation of Mutual Coupling in Irregular Planar Arrays
File Type: Conference Paper
Issue:Volume: S14 Numerical Methods for Analysis, Design and Measurement of Antennas I      Number:      Year: 2018
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Title: Energy Paradigms of Augmented Tags for the Internet of Things Deployment
File Type: Conference Paper
Issue:Volume: S33 Electromagnetic Techniques for the Internet of Things I      Number:      Year: 2017
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Title: EMX: Overcoming Silicon Chip EM Simulation Challenges for Passive Circuit Analysis and Model Development
File Type: Conference Paper
Issue:Volume: S23 Electromagnetic Modeling for Electronic Design Automation      Number:      Year: 2021
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Title: Electromagnetic Stimuli in Therapeutics and Resuscitation
File Type: Conference Paper
Issue:Volume: S53 Biological Effects of Electric, Magnetic and Electromagnetic Fields I      Number:      Year: 2017
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Title: Electromagnetic Diffraction Modeling: High Frequency Asymptotics vs. Numerical Techniques
Abstract: Electromagnetic diffraction modelling and recent numerical simulation approaches, on the canonical 2D non-penetrable wedge scattering problem, are reviewed in this introduction paper.
Author(s): L. Sevgi
File Type: Journal Paper
Issue:Volume: 32      Number: 7      Year: 2017
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Title: Development of Wideband L-Probe Coupled Patch Antenna
Abstract: The patch antenna fed by an L-shaped probe was proposed in 1998. This feeding method, and its modified version, the meandering strip, has led to the development of a new class of wideband patch antennas which can be operated in linear, circular or dual polarization with excellent performance characteristics. L-probe coupled patch antennas are simple in structure and low in material and production costs. Moreover, it can be designed with dual wideband performance which is very attractive for modern mobile communications. This paper presents a review of the general designs for linearly and circularly polarized L-probe patch antennas. Comparisons between measured and simulated results are presented. Methods for gain enhancement and cross polarization suppression are also introduced. The designs and performances of two dual-band wideband L-probe fed patch antennas are also described.
Author(s): Kwai Man Luk, Kai Fong Lee, Hau Wah Lai, Kwai Man Luk, Kai Fong Lee, Hau Wah Lai
File Type: Journal Paper
Issue:Volume: 22      Number: 1      Year: 2007
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Title: Development of the Incremental IEMF Method as an Analycital Proof for the Validity of FARS (Far-field Analysis of Radiation Sources)
File Type: Conference Paper
Issue:Volume: Advances in Integral Equation Based Techniques II      Number:      Year: 2009
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Title: Detect and Pointing Algorithm's Performance for a Planar Smart Antenna Array: A Review
Abstract: An adaptive antenna array combines the signal of each element, using some constraints to produce the radiation pattern of the antenna, while maximizing the performance of the system. Direction of arrival (DOA) algorithms are applied to determine the directions of impinging signals, whereas beamforming techniques are employed to determine the appropriate weights for the array elements, to create the desired pattern. In this paper, a detailed analysis of both categories of algorithms is made, when a planar antenna array is used. Several simulation results show that it is possible to point an antenna array in a desired direction based on the DOA estimation and on the beamforming algorithms. A comparison of the performance in terms of runtime and accuracy of the used algorithms is made. These characteristics are dependent on the SNR of the incoming signal.
Author(s): T. Varum, J. N. Matos, P. Pinho
File Type: Journal Paper
Issue:Volume: 30      Number: 8      Year: 2015
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Title: Coupled EM-Structural Analysis in Convected Coordinates
File Type: Conference Paper
Issue:Volume: S47 Integral Equation Solvers for Real-Life Applications I      Number:      Year: 2018
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Title: COMPUTER-BASED ELECTROMAGNETlC EDUCATION
Abstract: Computers provide an exciting opportunity for boosting electromagnetic education and corporate training. Animated graphics of the wave propagation phenomenon, visualization of the abstract and highly mathematical subjects, one-on-one and self-paced tutoring, and the ability to mimic often unavailable and expensive laboratory experiments are among the often-cited benefits of a computer-based electromagnetic education. In this paper, we review the activities of the NSF/IEEE Center for Computer Applications in Electromagnetic Education (CAEME). This Center was established to stimulate and accelerate the use of computers and software tools in EM education. A reflection on the extensive software package developed and distributed by the CAEME Center is described and examples of the developed software are presented. To help integrate available EM software in classroom teaching and corporate training, CAEME developed four multimedia lessons for instruction. These interactive media lessons integrate and allow individuals to interactively manipulate information from multimedia sources such as video, software, and animated graphics and also include instructional information such as quizzes and tutorials to help evaluate the students' performance. Features of these lessons are presented, and future developments in the Center's activities are described. [Vol. 8, No. 1, (1993), Special Issue on Computer Applications in Electromagnetics Education, pp 77-107]
Author(s): Magdy F. Iskander, Magdy F. Iskander
File Type: Journal Paper
Issue:Volume: 8      Number: 1      Year: 1993
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Title: Computational Electromagnetics for the Evaluation of EMC Issues in Multi-Component Energy Systems
Abstract: This paper reviews the physics based modeling based on the electromagnetic stray fields and interference in the electric power network. The low frequency as well as high frequency equivalent source modeling of the power components for the study of radiated and conducted electromagnetic compatibility were implemented. The 3-D finite element analysis with some modification were applied in the solution method, as well as meshing strategies for the simulation of large scale components. Moreover, the stray field of the components was utilized for improving the control of the machine-drive system using hardware in loop method. The optimization in the design of the components such as the power converter based on the EMC compliance was also applied. This was achieved by coupling MATLAB with 3-D finite element technique for applying the numerical optimization techniques. The results were verified experimentally.
Author(s): M. R. Barzegaran, O. A. Mohammed
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: COMPUTATION OF MULTIPOLE MOMENTS FOR SHORT THIN WIRE CHIRAL STRUCTURES
Abstract: This paper considers the computation of the multipole moments of small chiral wire structures. The multipole moments are reviewed and it is shown that the charge induced on the wire must be accurately computed. A quasistatic thin-wire Galerkin Method of Moments formulation has been developed to numerically compute the charge distribution. The chiral structures under consideration are on the borderline of "thin" and a Body of Revolution Method of Moments formulation has also been developed for use as a check on the accuracy of the thin-wire approximations. It is shown that the "standard" thin-wire formulation is not sufficiently accurate, but the relatively simple addition of an end-cap greatly improves the convergence and accuracy of the formulation with acceptable computation cost. Finally, the formulation is extended to include bent wires, permitting the electric and magnetic dipole moments as well as the electric quadrupole moment to be calculated for a small chiral structure. [Vol. 10, No. 3 (1995), Special Issue on Advances in the Application of Method of Moments to Electromagnetic Radiation and Scattering Problems, pp 129-138]
Author(s): Isak Petrus Theron, David Bruce Davidson, Johannes Hendrik Cloete, Isak Petrus Theron, David Bruce Davidson, Johannes Hendrik Cloete
File Type: Journal Paper
Issue:Volume: 10      Number: 3      Year: 1995
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Title: Compressive Processing for Computational Electromagnetics – Theoretical Basics, Current Trends and Advances
File Type: Conference Paper
Issue:Volume: 7-TA-5 Compressive Sensing in Applied Computational Electromagnetics - Trends and Advances      Number:      Year: 2018
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Title: Comparison and Analyzing of Propagation Models with Respect to Material, Environmental and Wave Properties
Abstract: This paper presents a study on a class of algorithms based on Uniform Theory of Diffraction (UTD) for multiple diffractions. Within this context Slope UTD with Convex Hull (S-UTD-CH) model based on Slope UTD and Fresnel zone concept was reviewed. S-UTD-CH model can be used for fast and more accurate field prediction for multiple diffractions in transition zone. An extensive simulation results for comparison of UTD based algorithms with respect to the computation time and accuracy was provided. Furthermore, the study shows how relative permittivity constant, conductivity and inner angle of wedge and polarization type affect the relative path loss.
Author(s): M. B. Tabakcioglu, D. Ayberkin, A. Cansiz
File Type: Journal Paper
Issue:Volume: 29      Number: 6      Year: 2014
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Title: Cloud Computing Simulation Tools for Nanophotonics at nanoHUB.org
File Type: Conference Paper
Issue:Volume: Computational Nanophotonics: Time – Domain Multiphysics, Meshless Methods and Non – Linear Optics      Number:      Year: 2013
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Title: Cloud Computing for the Science of Light: Nanophotonics Tools at nanoHUB.org
File Type: Conference Paper
Issue:Volume: Modeling of Metamaterials and Transformation Based Devices      Number:      Year: 2011
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Title: Characterization of a Planar Two-Arm Self-Complementary Square Spiral Antenna Using the Numerical Electromagnetics Code (NEC)
File Type: Conference Paper
Issue:Volume: Electromagnetic-Simulation-Driven-Design: Modeling and Optimization      Number:      Year: 2011
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Title: Characteristic Basis Function Method (CBFM)—An Iteration-free Domain Decomposition Approach in Computational Electromagnetics
Abstract: In this paper we review a novel Domain Decomposition (DD) approach, called the Characteristic Basis Function Method (CBFM), which tackles large-scale electromagnetic problems by generalizing the concept of principle of localization that forms the cornerstone of asymptotic methods. The paper shows that the problem of having to deal with large matrices that arise in the conventional formulation of large problems with the Method of Moments (MoM) can be obviated, by dividing the original large problem into a number of smaller sub-problems that are more manageable to handle. However, unlike the conventional DD approaches that typically rely upon iteration algorithms to account for the inter-coupling between the subdomains, the CBFM tackles the problem with direct solvers instead. It is possible to do this in the context of CBFM, because it reduces the original large system matrix into one whose size is orders of magnitude smaller, and is appropriately called the “reduced matrix.” Furthermore, an important salutary feature of CBFM is that the algorithm is naturally parallelizable, an attribute that distinguishes it from many other CEM solvers, and makes it well suited for parallel platforms that have become ubiquitous in recent years. This, in turn, enables us to take advantage of the power of these platforms and to solve, numerically efficiently, large problems that were well beyond our reach in the past. The paper also shows that the basic concepts of CBFM are quite general, and they not only apply to MoM, but can also be tailored for both FEM and FDTD. Index Terms─ Characteristic Basis Function Method (CBFM), Domain Decomposition, Method of Moments (MoM), Finite element Method (FEM), Finite Difference Time Domain (FDTD).
Author(s): R. Mittra
File Type: Journal Paper
Issue:Volume: 24      Number: 2      Year: 2009
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Title: Calculator of WPT Efficiency between Transmitting and Receiving Elements
File Type: Conference Paper
Issue:Volume: 1-3-D Wireless Power Transfer Supported by Computational Electromagnetics      Number:      Year: 2017
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Title: Beam Scanning Reflectarray Antennas: A Technical Review
File Type: Conference Paper
Issue:Volume: Student Paper Competition      Number:      Year: 2012
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Title: Beam Scanning Reflectarray Antennas: A Technical Review
File Type: Conference Paper
Issue:Volume: Latest Developments of Reflect/Transmit Array Antennas      Number:      Year: 2012
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Title: Avoiding the Time-static Simplification in the Simulation of Time-varying Materials
File Type: Conference Paper
Issue:Volume: S07 Advances in Electromagnetics of Complex Media and Metamaterials - I      Number:      Year: 2021
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Title: Artificial Intelligence Technology and Engineering Applications
Abstract: There has been sixty-year development of the artificial intelligence (AI) and the maturation of AI techniques is now leading to extensive applications and industrialization. In this paper, authors review the connotation and evolution of AI techniques and engineering applications. A four-layer framework of the AI technology system is summarized in this paper to help readers understand AI family. Engineering applications of AI techniques have made remarkable progress in the recent years, for instance, applications in fault diagnosis, medical engineering, petroleum industry and aerospace industry. By introducing the state-of-the-art of AI technologies, it can help the researchers in both engineering and science fields get ideas on how to apply AI techniques to solve application-related problems in their own research areas.
Author(s): X. Li, H. Jiang
File Type: Journal Paper
Issue:Volume: 32      Number: 5      Year: 2017
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Title: Application of the Radial Point Interpolation Method as Meshless Time-Domain Technique in Electromagnetics
File Type: Conference Paper
Issue:Volume: Student Paper Competition      Number:      Year: 2008
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Title: Application of the Radial Point Interpolation Method as Meshless Time-Domain Technique in Electromagnetics
File Type: Conference Paper
Issue:Volume: Recent Developments and Applications with Time-domain Modeling Techniques      Number:      Year: 2008
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Title: APPLICATION OF NUMERICAL MODELING TECHNIQUES IN ELECTROMAGNETIC HYPERTHERMIA
Abstract: Electromagnetic hyperthermia has been demonstrated to be a safe and useful adjuvant to ionizing radiation in the treatment of malignant tumors. However, applicators and systems for delivering the optimum treatment prescribed by the physicians are far from being available at present. Computer modeling can play a significant role in the design of better heating equipment and in improving the quality of the hyperthermia treatments currently being administered. There is an active ongoing research to develop suitable calculational models using a variety of numerical techniques. But several gaps exist in the current knowledge regarding the validity of these numerical simulations in the clinical context. The development of treatment planning systems similar to those used for radiation therapy requires resolution of these issues. Of the different numerical modeling approaches currently being developed, the finite-difference time-domain (FD-TD) technique has been extensively applied to calculate specific absorption rate (SAR) patterns in complex 3-D heterogeneous biological objects primarily because it is accurate and has a small computer burden relative to frequency-domain integral equation and finite element techniques. Following a brief review of the historical development of numerical modeling of electromagnetic interaction with biological structures in the hyperthermia context, examples of recent calculations using FD-TD technique in realistic situations in electromagnetic hyperthermia are provided. It has been observed from 2-D calculations, that the water bolus, routinely used in the clinic to provide energy coupling and surface (skin) temperature control, and the inhomogeneous tissue structures significantly modify the SAR patterns compared to patterns computed in planar and homogeneous structures. In conclusion, future areas of work are identified and discussed. [Vol. 7, No. 2, pp. 61-71 (1992), Special lssue on Bioelectromagnetic Computations]
Author(s): V. Sathiaseelan, A. Taflovel, M.J. Picket-Mayl, C. Reuterl, B. B. Mittal, V. Sathiaseelan, A. Taflovel, M.J. Picket-Mayl, C. Reuterl, B. B. Mittal
File Type: Journal Paper
Issue:Volume: 7      Number: 2      Year: 1992
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Title: Antennas Wrapped up on Slender Column
File Type: Conference Paper
Issue:Volume: S24 Mobile and Small Antennas I      Number:      Year: 2016
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Title: Antenna Developments for Military Applications
Abstract: A review of current, past and projected activities in antenna development indicates a broad spectrum of requirements, and subsequently a variety of innovations to meet these requirements for military radar and communications systems. Designing the antennas in the operating environment, known as in-situ design, is an important factor in guaranteeing the successful operation of the antenna in the field. This paper presents the basic blocks in antenna development, followed by examples of some antennas developed at the Army Research Laboratory for military systems and applications. These include Rotman lenses as beam formers for electronically scanning arrays; phased arrays using MEMS phase shifters at 30 GHz; a 76-GHz narrow beam, low-sidelobe antenna for collision avoidance radar; and other specialized antennas. Of special interest is an effort on developing and using metamaterials in antenna designs, where practical realizations of such materials have the potential of improving the performance and reducing the size of antennas.
Author(s): A. I. Zaghloul, S. J. Weiss, W. K. Coburn
File Type: Journal Paper
Issue:Volume: 25      Number: 1      Year: 2010
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Title: Anonymous Peer review. Time to Move on?
File Type: Newsletter Paper
Issue:Volume: 22      Number: 1      Year: 2007
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Title: An Overview of Equivalent Circuit Modeling Techniques of Frequency Selective Surfaces and Metasurfaces
Abstract: Circuit analysis of frequency selective surfaces is reviewed with the aim to underline range of validity of different models and their advantages in terms of simplicity and physical insight. The circuit approach is based on an equivalent representation of the FSSs with series or shunt connections of inductances and capacitances. Dense non-resonant periodic surfaces (i.e.: grid or patch arrays) can be analyzed analytically by computing the values of inductors or capacitors via the homogenization theory. As the lattice period increases with respect to the operating wavelength or the element shape becomes resonant, a fully analytical circuital approach fails, in particular, in the presence of thin substrates. However, simple circuit approaches can still be employed by deriving lumped parameters values via a quick pre-processing and then generalizing them. The results are accurate up to the resonant frequency region of the element. By including an additional lumped element it is possible, taking into account the effect of the first high order Floquet harmonic. The multi-mode formulation is also able to catch the highly nonlinear response of FSS screens in the grating lobe region provided that the current profile of the element does not change significantly.
Author(s): F. Costa, A. Monorchio, G. Manara
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: An Incomplete Review of Fast Multipole Methods–from Static to Wideband–as Applied to Problems in Computational Electromagnetics
Abstract: Fast multipole methods (FMM) and their immediate predecessors, tree codes, were developed in response to the need for solving Nbody problems that occur in applications as varied as biophysics, computational chemistry, astrophysics and electromagnetics. In all these areas, it is necessary to compute long range potentials of the form 1/R between a dense distribution of point charges, where R is the distance between any two charges. Often, repeated evaluation of these potentials is necessary. It is apparent that the cost of direct evaluation, which scales as O(N2) for N degrees of freedom, forms a fundamental bottleneck. FMM and tree methods ameliorate the cost associated with these computation; CPU times of these method scale as O(N). It stands to reason that FMM has had a seminal impact on a multitude of fields, so much so, that it was recognized as one of the top ten algorithms of the past century. A method to rapidly compute potentials of the form e-j κR/R soon followed. As the reader is aware, these potentials are the crux of integral equation based analysis tools in electromagnetics and the advent of these methods have transformed the face of computational electromagnetics. Consequently, the state of art of integral equation solvers has grown by leaps and bounds over the past decade. This paper attempts to present a detailed review of the state of art of FMM based methods that are used in computational electromagnetics, from the static to the high frequency regime.
Author(s): M. Vikram, B. Shanker
File Type: Journal Paper
Issue:Volume: 24      Number: 2      Year: 2009
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Title: Advances of Neural Network Modeling Methods for RF/Microwave Applications
Abstract: Abstract: This paper provides an overview of recent advances of neural network modeling techniques which are very useful for RF/microwave modeling and design. First, we review neural network inverse modeling method for fast microwave design. Conventionally, design parameters are obtained using optimization techniques by multiple evaluations of EM-based models, which take a long time. To avoid this problem, neural network inverse models are developed in a special way, such that they provide design parameters quickly for a given specification. The method is used to design complex waveguide dual mode filters and design parameters are obtained faster than the conventional EM-based technique while retaining comparable accuracy. We also review recurrent neural network (RNN) and dynamic neural network (DNN) methods. Both RNN and DNN structures have the dynamic modeling capabilities and can be trained to learn the analog nonlinear behaviors of the original microwave circuits from input-output dynamic signals. The trained neural networks become fast and accurate behavioral models that can be subsequently used in systemlevel simulation and design replacing the CPUintensive detailed representations. Examples of amplifier and mixer behavioral modeling using the neural-network-based approach are also presented.
Author(s): H. Kabir, Y. Cao, Y. Cao, Q. Zhang
File Type: Journal Paper
Issue:Volume: 25      Number: 5      Year: 2010
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Title: Advances in the Adjoint Variable Method for Time-Domain Transmission Line Modeling
File Type: Conference Paper
Issue:Volume: Advances in Time Domain Techniques      Number:      Year: 2005
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Title: Advances in the Adjoint Variable Method for Time-Domain Transmission Line Modeling
File Type: Conference Paper
Issue:Volume: Advances in Time Domain Techniques      Number:      Year: 2005
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Title: Advanced Modeling of Characteristic Mode Theory for Antenna Applications
File Type: Conference Paper
Issue:Volume: 2-1-A Brainstorm for Computational Electromagnetics: What We Have Achieved and What We Will Do I      Number:      Year: 2017
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Title: Active Millimeter Wave Imaging System with Sparse Antenna Array
File Type: Conference Paper
Issue:Volume: 2-4-D Millimeter Wave/THz Imaging I      Number:      Year: 2017
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Title: Active Metamaterial Incorporating Gain Device/Medium: A Review
Abstract: Metamaterials intrigue many exciting applications in the broad electromagnetic spectrum ranging from microwave to optics. However, many of the envisaged applications still remain in theory, largely because of the intrinsic loss and dispersion associated with passive metamaterials. Incorporating active devices or media into conventional passive metamaterial structures for loss compensation, as well as dispersion control, is very attractive and may finally enable many desired applications. In addition, because of the added design degree of freedom in active metamaterials, new and rich physical phenomena and insights can be discovered. In this paper, we review the recent progress in the realm of active, gain-assisted metamaterials. Physical limitations on loss and bandwidth of metamaterials are firstly discussed. Recent experimental efforts in transmission-line and volumetric metamaterials with net gain in the microwave and optical regime are then examined. The idea of utilizing non-Foster active devices to reduce the dispersion and achieve broad bandwidth is also presented. Finally, one of the important issues of active metamaterial design, stability, is briefly discussed.
Author(s): Q. Tang, H. Xin
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: A VOLUME INTEGRAL CODE FOR EDDY-CURRENT NONDESTRUCTIVE EVALUATION
Abstract: This paper is an extension of J. R. Bowler, H. A. Sabbagh, and L. D. Sabbagh, "A Computational Model of Eddy-Current Probes Over a Stratified Composite Workpiece," which was presented at the 4th Annual Review of Progress in Applied Computational Electromagnetics, Monterey, CA, March 1988. It describes an application of modern methods of computational electromagnetics to the problem of eddy-current nondestructive evaluation (NDE). Specifically, a volume integral equation is developed that can be used to model eddy-current probes with ferrite cores, or it can be used to compute flaw-field interactions. Both of these problems are of considerable importance in applying electromagnetic techniques to NDE, for they are intimately involved in detecting flaws, and inverting eddy-current data for reconstructing flaws. The model is fully three-dimensional, and the discretized integral equation is solved iteratively using conjugate gradients and FFT techniques. Problems with 12,000 unknowns are being routinely solved on the Alliant FX/ 1 minisupercomputer in reasonable times. The model is used to compute such important probe parameters as impedance and coupling. It is also used to compute the electromagnetic response of flaws as the geometry of the flaw changes, or as a function of frequency. [Vol. 4, No. 1, pp.3-22 (1989)]
Author(s): Harold A. Sabbagh, John R. Bowler, L. David Sabbagh, Harold A. Sabbagh, John R. Bowler, L. David Sabbagh
File Type: Journal Paper
Issue:Volume: 4      Number: 1      Year: 1989
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Title: A Uniaxial Time-Domain Wave Potential Analysis of the Electromagnetic Field in Nonuniform Media
File Type: Conference Paper
Issue:Volume: Advanced Computational Techniques for System Design      Number:      Year: 2003
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Title: A Summary Review on 25 Years of Progress and Future Challenges in FDTD and FETD Techniques
Abstract: The finite-difference time-domain (FDTD) method has established itself among the most popular methods for the numerical solution of Maxwell equations. Reasons for its popularity include its versatility, matrix-free characteristic, ease for parallelization, and low computational complexity. In recent years, the finite-element time-domain (FETD) has also become another very popular algorithm for solving time-domain Maxwell equations due to its geometrical flexibility and the steady growth in hardware computing power. In this review, we succinctly recollect some of the milestones in the development of FDTD and FETD over the last 25 years, and briefly discuss some challenges for the future development of these two algorithms.
Author(s): F. L. Teixeira
File Type: Journal Paper
Issue:Volume: 25      Number: 1      Year: 2010
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Title: A ROMANIAN EXPERIENCE IN COMPUTER-AIDED ELECTROMAGNETIC EDUCATION
Abstract: The paper presents the actual interests in computer-aided electromagnetic education (CAEE) at the Electrical Engineering Department from Polytechnic Institute of Bucharest, Romania. The actual state of computer use on different levels of undergraduate and graduate education is presented. Specifically, an overview of the undergraduate theoretical training and practical applications is described, and research topics for graduate reports and doctoral dissertations are discussed. Issues related to hardware utilities are reviewed, and future projects aimed at improving the CAEE capabilities in Romania are described. The material is based on significant selected references. [Vol. 8, No. 1, (1993), Special Issue on Computer Applications in Electromagnetics Education, pp 125-137]
Author(s): Mihaela Morega, Daniel Ioan, Mihaela Morega, Daniel Ioan
File Type: Journal Paper
Issue:Volume: 8      Number: 1      Year: 1993
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Title: A Review of Ultra-Wideband Array Antennas
File Type: Conference Paper
Issue:Volume: 7-TA-4 In Celebration of 70th Birthday of Prof. Jia-dong Xu I      Number:      Year: 2018
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Title: A Review of the Modal Decomposition Matrix for Calculating the Far Field of an Infinitely Flanged Rectangular Waveguide
Abstract: We determine the radiation from an infinitely flanged rectangular waveguide using the modal decomposition matrix (MDM) method. The MDM method computes the electromagnetic field components at the aperture in the Fourier domain by representing the radiated field in terms of a sampling of the free-space transverse wave number. The results of the MDM approach show good agreement with numerical approaches using commercial electromagnetic modeling software.
Author(s): G. A. Mitchell, W. Wasykiwskyj
File Type: Journal Paper
Issue:Volume: 33      Number: 12      Year: 2018
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Title: A Review of Terahertz Imaging Systems in CMOS
File Type: Conference Paper
Issue:Volume: 3-2-D EM + Active Device Modeling for MMIC and 5G      Number:      Year: 2017
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Title: A Review of Statistical Methods for Comparing Two Data Sets
Abstract: Statistical approaches to compare data for validation of computational electromagnetics have been used for several years. They provide an accepted means of obtaining a numerical value to quantify the data under consideration. However, the use and meaning of these ‘numbers’ depends, by necessity, on the application. This paper provides an overview of some of the most widely applicable techniques, relating the output of these to visual assessment. It further includes comparison with the FSV (Feature Selective Validation) method allowing a triangulation between statistical approaches, visual approaches and heuristic approaches to validation. It is important that the decision to use or reject a particular technique for validation is based on a rational and objective selection approach. This paper suggests a framework to support this selection approach.
Author(s): A. Duffy, A. Orlandi, A. Duffy, A. Orlandi
File Type: Journal Paper
Issue:Volume: 23      Number: 1      Year: 2008
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Title: A Review of Recent Advances in Designing True-Time-Delay Microwave Lenses Exploiting Metamaterials with Non-Resonant Constituting Unit Cells
Abstract: This paper presents a review of recent developments in the design of planar microwave lenses capable of operating over broad bandwidths in a true-time-delay fashion. The lenses discussed in this paper consist of planar apertures populated with miniature, sub-wavelength time-delay units. Each time delay unit is the unit cell of an appropriately-designed Frequency Selective Surface (FSS) with non-resonant, sub-wavelength constituting unit cells and is designed to provide a constant time-delay unit over the frequency range at which the lens operates. Designs that exploit both band-pass and low-pass FSSs are presented and discussed. Because of the non-resonant nature of their constituting unit cells and their small dimensions, such lenses can operate over broad bandwidths with wide fields of views. When used in conjunction with appropriately designed feed antennas, these lenses can be used in multi-beam, high-gain, broadband antenna apertures.
Author(s): N. Behdad
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: A Review of Perfectly Matched Absorbers for the Finite-Volume Time-Domain Method
Abstract: Different implementations of planar perfectly matched absorbers are studied under the unified framework of the Finite-Volume Time-Domain (FVTD) method. This comparative analysis allows to discuss the similarities existing between the theoretical models and explores the differences in their practical implementation and numerical performance in the framework of the FVTD method. Numerical experiments for performance analysis of the different PML models are conducted in terms of discretization and angle of incidence using waveguide models. The results are compared to theoretically expected values and to the first-order Silver M¨uller absorbing boundary condition.
Author(s): T. Kaufmann, K. Sankaran, C. Fumeaux, R. Vahldieck, T. Kaufmann, K. Sankaran, C. Fumeaux, R. Vahldieck
File Type: Journal Paper
Issue:Volume: 23      Number: 3      Year: 2008
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Title: A Review of Path Integral Time Domain Method
File Type: Newsletter Paper
Issue:Volume: 19      Number: 3      Year: 2004
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Title: A Review of Advanced Characteristic Mode Theories for Complex Electromagnetic Problems
File Type: Conference Paper
Issue:Volume: 4-1-A Brainstorm for Computational Electromagnetics: What We Have Achieved and What We Will Do II      Number:      Year: 2017
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Title: A Review and Application of the Finite-Difference Time-Domain Algorithm Applied to the Schrodinger Equation
Abstract: This paper contains a review of the FDTD algorithm as applied to the time-dependent Schrodinger equation, and the basic update equations are derived in their standard form. A simple absorbing boundary condition is formulated and shown to be effective with narrowband wave functions. The stability criterion is derived from a simple, novel perspective and found to give better efficiency than earlier attempts. Finally, the idea of probability current is introduced for the first time and shown how it can be used to radiate new probability into a simulation domain. This removes the need to define an initial-valued wave function, and the concept is demonstrated by measuring the transmission coefficient through a potential barrier.
Author(s): J. R. Nagel
File Type: Journal Paper
Issue:Volume: 24      Number: 1      Year: 2009
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Title: A New Closed-Form Expression for Dispersion Characteristics of Fundamental Mode of SIW by Least Squares Method
Abstract: A new and accurate closed-form expression is introduced using least squares method (LSM) to calculate propagation constant of substrate integrated waveguide (SIW) at its fundamental mode of operation. The derived equation is a function of geometrical parameters of the structure and accurately estimates cutoff frequency of the dominant mode. The LSM is used to determine the effective width of the SIW structure. A review and comparisons with recently published simulation and measurement results are also provided, which verify the accuracy of the proposed method.
Author(s): M. GH. Alijani, M. H. Neshati
File Type: Journal Paper
Issue:Volume: 30      Number: 8      Year: 2015
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Title: 25 Years of Progress and Future Challenges in Integral Equation Solvers
File Type: Conference Paper
Issue:Volume: 25 Years of Progress and Future Challenges in Applied Computational Electromagnetics I      Number:      Year: 2009
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Title: 25 Years of Progress and Future Challenges in FDTD/FETD Techniques and Applications
File Type: Conference Paper
Issue:Volume: 25 Years of Progress and Future Challenges in Applied Computational Electromagnetics II      Number:      Year: 2009
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Title: 25 Years of Progress and Future Challenges in Boundary-Element Based Field-Circuit and Multiphysics Solvers
File Type: Conference Paper
Issue:Volume: 25 Years of Progress and Future Challenges in Applied Computational Electromagnetics II      Number:      Year: 2009
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Title: Using MATLAB to Control Commercial Computational Electromagnetics Software
Abstract: This paper provides details on how to use MATLAB to control some commercial electromagnetics software packages. FEKO is an example that can be directly called from MATLAB. Other commercial software, such as CST Microwave Studio and Ansoft HFSS, require a scripting language interface. An example of a design of an inset rectangular patch antenna is presented using a direct call to FEKO and a Visual Basic for Applications interface to CST Microwave Studio are presented.
Author(s): R. L. Haupt, R. L. Haupt
File Type: Journal Paper
Issue:Volume: 23      Number: 1      Year: 2008
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Title: Using Logo-Antenna Based RFID Tags forAdvertising
File Type: Conference Paper
Issue:Volume: Modeling of RFID Devices and Systems      Number:      Year: 2009
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Title: Using Logo-Antenna Based RFID Tags for Advertising
File Type: Conference Paper
Issue:Volume: Student Paper Competition I      Number:      Year: 2009
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Title: Using Folded Open-Loop Ring Resonator to Design a Common-Mode Suppression and Frequency Adjustable Balun-Bandpass Filter
Abstract: A compact and simple balun-bandpass filter was investigated by using a pair of half-wavelength open-loop ring resonators (OLRRs) and two microstrip lines. The balun-bandpass filter could be designed easily with a different center frequency by changing the path length of OLLRRs. The design methodology was adopted based on EM simulation to obtain these optimally designed parameters of the OLRRs, and microstrip lines and the filters were fabricated on FR4 substrate. The filters with the frequencies of 2.6 GHz and 5.2 GHz were designed to prove the characteristic of frequency adjustable and they were fabricated with the properties of wide bandwidth and low insertion loss. The balun-bandpass filters presented an excellent inband balanced performance with common-mode rejection ratio over than 40 dB and 34 dB in the passbands of 2.6 GHz and 5.2 GHz, respectively. Good correlation was seen between simulation and measurement, and the result showed that first run pass had been achieved in the majority of our design.
Author(s): C.-M. Chen, S.-J. Chang, J.-C. Zheng, J.-C. Liou, C.-F. Yang
File Type: Journal Paper
Issue:Volume: 31      Number: 1      Year: 2016
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Title: Using FEKO Software for Analysis of Radiated Electric Field by Power Converters
File Type: Conference Paper
Issue:Volume: FEKO Modeling and Analysis - 2      Number:      Year: 2006
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Title: Using FEKO for Electromagnetic Analysis of Carbon-Fiber Composite Structures
File Type: Conference Paper
Issue:Volume: Electromagnetic Simulation using FEKO      Number:      Year: 2011
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Title: Using Electromagnetic Band Gap (EBG) Superstrate Layer to Enhance the Bandwidth and Gain of a Dual Band Microstrip Patch Antenna
File Type: Conference Paper
Issue:Volume: Metamaterial Structures with Application to Guided-Wave Electromagnetics and Antennas      Number:      Year: 2007
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Title: Using Efficient Model-Based Parameter Estimation for Pole-Free Solutions of Modal Propagation Constants, as Applied to Shielded Planar Structures
Abstract: A fast and efficient adaptive sampling algorithm is applied to model-based parameter estimation of a Method-of-Lines implementation of two- and three-layer shielded planar structures, creating a pole-free function for the calculation of the propagation constants. The technique minimizes the number of characteristic equation evaluations, and hence reduces the computation time by orders of magnitude when compared to methods using the characteristic equation directly. Examples of a shielded microstrip line and a finline structure are shown below. Between 3 and 15 evaluations of the characterisic function are typically required per determination of an imaginary or real zero.
Author(s): Robert Lehmensiek, Petrie Meyer, Robert Lehmensiek, Petrie Meyer
File Type: Journal Paper
Issue:Volume: 16      Number: 1      Year: 2001
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Title: Using Circuit Simulation Optimization to Determine the Electrical Properties of Polymeric Composite Materials
File Type: Conference Paper
Issue:Volume: Computational Methods for Nondestructive Evaluation and Materials Characterization      Number:      Year: 2007
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Title: Using Antenna Measurements in Numerical Solutions
File Type: Conference Paper
Issue:Volume: S16 EM Modeling using FEKO      Number:      Year: 2015
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Title: Using an Approximate Streamline Upwind/Petrov-Galerkin Stabilization Matrix for the Solution of Maxwell’s Equations in Dispersive Materials
File Type: Conference Paper
Issue:Volume: S17 Time Domain Methods I      Number:      Year: 2018
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Title: Using Adaptive Estimation to Minimize the Number of Samples Needed to Develop a Pattern to a Specified Uncertainty
Abstract: Obtaining far-field patterns in electromagnetics or acoustics, although generally not as computationally expensive as solving for the sources induced on an object, can none-the-less at times be a substantial fraction of the overall computer time associated with some problems. This can be especially the case in determining the monostatic radar cross section of large objects, since the current distribution must be computed for each incidence angle or when using physical optics to determine the radiation patterns of large reflector antennas. In addition, when employing the point sampling and linear interpolation of the far field that is most often used to develop such patterns, it can be necessary to sample very finely in angle to avoid missing fine details such as nulls. A procedure based on model-based parameter estimation is described here that offers the opportunity of reducing the number of samples needed while developing an easily computed and continuous representation of the pattern. It employs windowed, low-order, overlapping fitting models whose parameters are estimated from the sparsely sampled far-field values. The fitting models themselves employ either discrete-source approximations to the radiating currents or Fourier models of the far field. For the cases investigated, as few as 1.5 to 2 samples per far-field lobe are found to be sufficient to develop a radiation-pattern estimate that is accurate to 0.1 dB, and 2.5 samples per lobe for a simple scatterer. In general, however, the sampling density is not determined by the lobe count alone, but by the effective rank of the field over the observation window, which in turn is a function of both the aperture size and the spatial variation of the source distribution within that aperture.
Author(s): Edmund K. Miller, Edmund K. Miller
File Type: Journal Paper
Issue:Volume: 17      Number: 3      Year: 2002
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Title: Using Adaptive Cross Approximation for Efficient Calculation of Monostatic Scattering with Multiple Incident Angles
Abstract: An adaptive cross approximation (ACA) based method is proposed for the fast analysis of the monostatic radar cross-section (RCS). Using the low-rank property, several largest eigenvalues and corresponding eigenvectors of the multiple right hand sides can be computed and saved efficiently by the ACA algorithm. The iterative solution of linear equations is required at these principle eigenvectors. Compared with solving linear equations at each angle repeatedly, the proposed method is able to greatly reduce the computation time. In order to efficiently solve the linear equations, the flexible general minimal residual (FGMRES) iterative solver is applied to compute the coefficients of Rao-Wilton-Glisson (RWG) basis functions. Numerical results demonstrate that the proposed method is efficient for monostatic RCS calculation with high accuracy.
Author(s): Z. Liu, R. Chen, J. Chen, Z. Fan
File Type: Journal Paper
Issue:Volume: 26      Number: 4      Year: 2011
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Title: NON-INVASIVE ACTIVE THERMOMETRY WITH A MICROWAVE TOMOGRAPHIC SCANNER IN HYPERTHERMIA TREATMENTS
Abstract: In this work the active microwave tomographic imaging of tissue temperature changes induced in deep hyperthermia treatments is studied. The thermal images would allow to monitor and optimize the treatment, increasing its efficacy and avoiding the heating of healthy tissues. As some hyperthermia systems are based on a cylindrical geometry, it is possible to integrate a microwave imaging array in the same structure, providing a non-invasive tool for the monitoring and control. The application of this technique to deep hyperthermia treatments is investigated by numerical simulations and experimentally on two phantoms of thorax and pelvis, using a prototype for microwave tomography recently developed [Jofre et al, 1990]. lVol. 7, No. 2, pp. 121-127 (1992), Special Issue on Bioelectromagnetic Computations]
Author(s): J. J. Mallorqui, A. Broquetas, L. Jofre, A. Cardama, J. J. Mallorqui, A. Broquetas, L. Jofre, A. Cardama
File Type: Journal Paper
Issue:Volume: 7      Number: 2      Year: 1992
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Title: COMPUTATIONAL METHOD FOR POWER LINE MAGNETIC FIELD EVALUATION
Abstract: The paper reports a model for the power line magnetic field evaluation. The obtained results for three different power lines (380 kV double circuit,380 kV single circuit, 220 kV double circuit) was validated with measurement data. Calculated and corresponding measured data were found in good agreement. The influence of geometrical and electrical power line parameters, such as the spatial configuration of the conductors and line phase sequences, is evaluated and discussed. Data on the influence of adjacent line span on the field are also reported. The method can be used for prediction of human exposure in epidemiological studies. [Vol. 7, No. 2, pp. 148-161 (1992), Special Issue on Bioelectromagnetic Computations]
Author(s): Santi Tofani, Giovanni d'Amore, Giancarlo Bonazzola, Giovanni Fiandino, Santi Tofani, Giovanni d'Amore, Giancarlo Bonazzola, Giovanni Fiandino
File Type: Journal Paper
Issue:Volume: 7      Number: 2      Year: 1992
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Title: THE APPLICATION OF NESTED DISSECTION TO THE SOLUTION OF A 2.5D ELECTROMAGNETIC PROBLEM
Abstract: We use the method of nested dissection to solve a 2.5D finite difference electromagnetic problem. This method is considered in some detail, and we have found that the expected theoretical run time savings over more common methods are realised in practice. The program has been used to model EM propagation in coal seams with a view to detecting seam disruptions, which can cause a loss of production in longwall mining operations. Various experimental results and a field survey are discussed and we are able to use these results to construct a physically reasonable model which explains the field data. Some further realistics geological structures are modelled and a comparison between our modelling program and several independent methods shows satisfactory agreement.
Author(s): G. H. Smith, P. R. Williamson, K. Vozoff, G. H. Smith, P. R. Williamson, K. Vozoff
File Type: Journal Paper
Issue:Volume: 5      Number: 2      Year: 1990
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Title: FOUR-ELEMENT BEVERAGE ARRAY
Abstract: An experimental four-element high-frequency Beverage antenna array has been devised for tests on medium range and long range ionospheric circuits. The radiation pattern of the experimental array was calculated using Numerical Electromagnetics Code (NEC) and found to be skewed in azimuth. The antenna installation was subsequently modified in accordance with NEC predictions and the desired beam direction was obtained. Measurements confirmed that the NEC predictions were valid. [Vol. 1, No. 1, pp. 15-20 (1986)]
Author(s): D. V. Campbell, P. Cunningham, P. Dubowicz, K. Loffer, D. V. Campbell, P. Cunningham, P. Dubowicz, K. Loffer
File Type: Journal Paper
Issue:Volume: 1      Number: 1      Year: 1986
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Title: The application of nested dissection to the solution of a 2.5D electromagnetic problem
Abstract: We use the method of nested dissection to solve a 2.5D finite difference electromagnetic problem. This method is considered in some detail, and we have found that the expected theoretical run time savings over more common methods are realised in practice. The program has been used to model EM propagation in coal seams with a view to detecting seam disruptions, which can cause a loss of production in longwall mining operations. Various experimental results and a field survey are discuessed and we are able to use these results to construct a physically reasonable model which explanes the field data. Some further realistic geological structures are modelled and a comparison between out modelling program and several independent methods show satisfactory agreement.
Author(s): G.H. Smith, P.R. Williamson, K. Vozoff, G.H. Smith, P.R. Williamson, K. Vozoff
File Type: Journal Paper
Issue:Volume: 15      Number: 2      Year: 2000
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Title: Linear Triangles versus Biquadratic Quadrangles in RCS computations
Abstract:
Author(s): A. Herschlein, J. von Hagen, D. Löffler, W. Wiesbeck, A. Herschlein, J. von Hagen, D. Löffler, W. Wiesbeck
File Type: Journal Paper
Issue:Volume: 20      Number: 3      Year: 2005
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Title: Digital joint phase and sampling instant synchronisation for UMTS standard
File Type: Conference Paper
Issue:Volume: System Architectures and Analysis      Number:      Year: 2005
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Title: Characterizing Dispersion in the Enclosed-Space Radio Channel using a Composite Mode Model
File Type: Conference Paper
Issue:Volume: Propagation Channel Characterization      Number:      Year: 2005
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Title: Deterministic Channel Modeling and Performance of Monopolarized and Multipolarized MIMO Wireless Channels
File Type: Conference Paper
Issue:Volume: MIMO and Diversity System Characterization      Number:      Year: 2005
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Title: Real Time Angle of Arrival Estimation for GSM Signals
File Type: Conference Paper
Issue:Volume: Direction of Arrival Estimation      Number:      Year: 2005
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Title: Active Frequency Selective Surfaces for Antenna Applications Electronically to Control Phase Distribution and Reflective/Transmissive Amplification
File Type: Conference Paper
Issue:Volume: Phased Array and Active Antennas      Number:      Year: 2005
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Title: Development of Time-Domain Surface Macromodels From Material Measurements
File Type: Conference Paper
Issue:Volume: Advanced EMC Modeling      Number:      Year: 2007
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Title: Reduction of Sensitivity to Measurement Errors in the Derivation of Equivalent Models of Emission in Numerical Computation
Abstract: In this paper, the accuracy of an equivalent dipole model for representing electromagnetic emissions from printed circuit boards (PCB) is studied. The optimization of nearfield measurement parameters and required PCB parameters for building a numerical model are discussed and their impact on the accuracy of emission predictions is examined.
Author(s): X. Tong, D. W. P. Thomas, A. Nothofer, C. Christopoulos, P. Sewell
File Type: Journal Paper
Issue:Volume: 26      Number: 7      Year: 2011
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Title: Non-linear Dielectrics and Ferrites in ICEPIC
File Type: Conference Paper
Issue:Volume: Multi-Physics Modeling and Simulations      Number:      Year: 2012
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Title: Application of the Sliding Surface Method with 3D Finite Element Analyses of a Hybrid Magnetic Bearing
File Type: Conference Paper
Issue:Volume: Low-Frequency Computational Electromagnetics      Number:      Year: 2009
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Title: A Simplified Analytical Solution for Characterizing Edge Currents Along a Finite Ground Plane
File Type: Conference Paper
Issue:Volume: Modeling and Simulation in Electromagnetic Engineering      Number:      Year: 2013
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Title: Extended Scheme using Equivalent Dipoles for Characterizing Edge Currents Along a Finite Ground Plane
Abstract: For the assessment of radiated fields, a simplified analytical solution that approximates the effects of the currents induced at the edges of a finite ground plane is presented. These edge currents are induced by the actual current sources on the plane. This method can be used in characterizing the electromagnetic (EM) emission from any practical PCB and avoids the need for using high-frequency techniques in evaluating effects due to diffraction.
Author(s): C. Obiekezie, D. W. Thomas, A. Nothofer, S. Greedy, L. R. Arnaut, P. Sewell
File Type: Journal Paper
Issue:Volume: 28      Number: 11      Year: 2013
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Title: Convex Optimization Based Sidelobe Suppression for Adaptive Beamforming with Subarray Partition
Abstract: This paper proposes a convex optimization based method to suppress sidelobe in adaptive beamforming at subarray level. Usually phase shift rather than amplitude tapering is implemented at element level to maximize signal to noise ratio. Nevertheless, sidelobe control can be realized at subarray level. The proposed approach is realized by adding a constraint minimizing the difference between weights at subarray level and element-level Chebyshev synthesis into the optimal conditions. Compared with penalty function method, simulations show that for a uniform linear array, the proposed method can suppress sidelobe level considerably, especially the lobes close to mainlobe. Furthermore, it is able to produce better shaped main lobe, which is extremely close to the referenced pattern.
Author(s): S. Xiaofeng, X. Jia, Z. Ying, K. Ling
File Type: Journal Paper
Issue:Volume: 29      Number: 1      Year: 2014
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Title: A Transparent UWB Antenna with a 5 to 6 GHz Band Notch Using Two Split Ring Resonators
Abstract: A miniaturized thin film transparent ultrawideband (UWB) antenna design with a band notch is presented. A pair of split-ring resonators (SRRs) is placed besides the radiating element to realize the band notch centered at 5.5 GHz. The proposed transparent antenna covers the whole 3.1 to 10.6 GHz UWB frequency band with a notch from 5 to 6 GHz to isolate interferences from wireless local area network (WLAN) and dedicated short-range communication (DSRC) applications. The transparency of this antenna of up to 80% is enabled by the fabrication on a conductive silver coated thin film (AgHT-8). Hence, the proposed transparent antenna is a suitable for UWB home entertainment network (IEEE 1394 over UWB network) for green building applications, where high data rates are required for multimedia transfer. Implementation of the proposed transparent antenna will reduce the space consumption due to its very low thickness and low profile, while at the same time increasing the aesthetic values of the installed wireless system due to its high transparency.
Author(s): M. S. A. Rani, S. K. A. Rahim, P. J. Soh, B. M. Saad, M. I. Sabram, M. F. M. Yusoff
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Detection of the Faulty Sensors on Basis of the Pattern Using Symmetrical Structure of Linear Array Antenna
Abstract: In this paper, a simple method is proposed to diagnose the position of the damaged sensors. The position of the damaged sensors is diagnosed on the basis of the null depth level and the number of nulls for the degraded radiation pattern. The method is initiated with tabulation of the array radiation pattern with a single damaged sensor. The corresponding pattern is set as the reference to the radiation pattern of the failed sensors. The tabulated damaged array sensors are compared to a configuration of the assumed damaged sensor. The radiation pattern with deeper null depth level will be the location of the damaged sensor. Moreover, the symmetrical sensor damaged (SSD) technique diagnose the position of damaged sensor, in which on the basis of nulls one can detect the location of damaged sensors. The proposed method diagnoses the location of damaged sensors on the basis of pattern without complex computation as compared to available methods.
Author(s): S. U. Khan, M. K. A. Rahim, N. A. Murad, F. Zubir, O. Ayop, M. F. M. Yusoff, M. R. Hamid, R. Dewan
File Type: Journal Paper
Issue:Volume: 32      Number: 4      Year: 2017
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Title: Crucial Parameters and Optimization of High-Speed Bearingless Drives
Abstract: Bearingless drives integrate the functionality of magnetic bearings and an electric machine into a single device. While this integration allows very compact drives offering all advantages of magnetic levitation, the design process becomes significantly more complex. This work deals with the numerous topological and geometric design decisions which need to be taken for such a bearingless drive. Additionally, the definition of suitable optimization targets for the electromagnetic simulation process is outlined. The proposed guidelines generate a complex relationship of different dependencies which is then fed into the MagOpt optimizer for the design of a high speed bearingless disk drive, which allows verifying the optimization results through measurement results from two prototype drives.
Author(s): H. Mitterhofer, S. Silber
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Ultra-Wideband Six-port Network Constructed by 90° and In-Phase Power Dividers
Abstract: This article proposes a six-port network design with an ultra-wideband operation from 3.1 to 10.6 GHz. The proposed six-port configuration is constructed by two types of power dividers with different phase characteristics of 0° (in-phase) and 90°. The new proposed configuration eliminates one unused port of the conventional six-port. Both components forming the proposed six-port are designed utilizing the microstrip-slot technique to accomplish the designated UWB operating frequency. The six-port is designed via the use of CST Microwave Studio (CST MWS) and realised by applying Rogers TMM4 substrate. Comparable simulated and measured performances are achieved in terms of S-parameters and phase differences between each consecutive port across UWB frequency range.
Author(s): N. Seman, K. H. Yusof, M. H. Jamaluddin, T. A. Rahman
File Type: Journal Paper
Issue:Volume: 34      Number: 5      Year: 2019
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Title: Ultra Wideband Power Divider Design Implementing Microstrip with Slotted Ground
Abstract: This article proposes a compact design of a two-section power divider, which operates over an ultra wideband frequency range of 3-11 GHz. The design approach of microtrip with slotline at the ground plane is applied to reduce the size of the circuit and to achieve wide bandwidth coverage. The rectangular slots are implemented at the ground plane, which is positioned symmetrically underneath the second and third arms of each microstrip quarter-wave transformer to reduce its length up to 33.34%. These attributes lead to an easily fabricated 20 mm x 23 mm compact power divider with a reduced size (by 23.33%). The bandwidth performance is improved up to 19.4% compared to a conventional divider. The design is realized by implementing the Rogers TMM4 substrate and simulated by using CST Microwave Studio. The power divider is verified by using a vector network analyzer (VNA). A good agreement between simulation and fabrication is achieved in terms of return loss, isolation and transmission coefficients across the UWB frequency range.
Author(s): N. Seman, K. H. Yusof, M. H. Jamaluddin, T. A. Rahman
File Type: Journal Paper
Issue:Volume: 34      Number: 8      Year: 2019
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Title: Ground Penetrating Radar Radargram Filter using Singularity Expansion Method
File Type: Conference Paper
Issue:Volume: S12 Sparse Array Processing and Radar Sensing      Number:      Year: 2020
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Title: Investigation of Antennas for Car-to-Car Communications
File Type: Conference Paper
Issue:Volume: S17 Computational Electromagnetics, Advanced Algorithms and Emerging Applications/ High Performance Computing in Electromagnetics      Number:      Year: 2020
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Title: A High Gain Lens-Coupled On-Chip Antenna Module for Miniature-Sized Millimeter-Wave Wireless Transceivers
Abstract: This paper presents high gain and compact Transmit/Receive (TX/RX) integrated antennas in a standard BiCMOS 130nm technology for millimeter-scale millimeter-wave (mm-wave) applications, including high data rate radios and high resolution radars. The proposed TX/RX antenna module utilizes an integrated dipole antenna for the receiver and a slot antenna for the transmitter, placed orthogonally. The achieved gain and radiation efficiency are 5.7dBi and 41.3% for the slot antenna, respectively, and 6dBi and 39% for the dipole antenna. The link budget is improved by 16dB by optimization on the geometry as well as application of a high resistivity hemispheric silicon dielectric lens.
Author(s): M. Moosavifar, D. Wentzloff
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: DOA Estimation in Heteroscedastic Noise with sparse Bayesian Learning
Abstract: We consider direction of arrival (DOA) estimation from long-term observations in a noisy environment. In such an environment the noise source might evolve, causing the stationary models to fail. Therefore a heteroscedastic Gaussian noise model is introduced where the variance can vary across observations and sensors. The source amplitudes are assumed independent zero-mean complex Gaussian distributed with unknown variances (i.e., source powers), leading to stochastic maximum likelihood (ML) DOA estimation. The DOAs are estimated from multisnapshot array data using sparse Bayesian learning (SBL) where the noise is estimated across both sensors and snapshots.
Author(s): P. Gerstoft, C. F. Mecklenbrauker, S. Nannuru, G. Leus
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: Uniaxial Dielectric Waveguide Filter Design Accounting for Losses Using Mode Matching Technique
Abstract: Dielectric filters can provide compact solutions for filter design problems. However, most dielectrics exhibit uniaxial properties, as well as, losses that will undoubtedly affect performance if not accounted for. This paper derives dispersion relations for lossy uniaxial media in dielectric waveguides and also accounts for lossy conducting walls. The waveguide discontinuity problem in the presence of lossy uniaxial media and finite conductivity waveguide walls, is calculated by mode matching technique and the results are applied to a Ka band filter. The design specifications for the proposed filter are a 32.5 GHz center frequency with 6%. Good agreement between simulated and measured results are shown.
Author(s): L. Murphy, J. Mautz, M. Yazdani, E. Arvas, S. Tozin
File Type: Journal Paper
Issue:Volume: 29      Number: 7      Year: 2014
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Title: Ultrawide band Negative Refraction Based on Moving Media Concept
Abstract: The anomalous wave propagation in a homogeneous, isotropic and lossless medium that moves with a constant velocity along the axis of a rectangular waveguide; and its interesting properties lead us to the fact that the moving media may be regarded as double negative metamaterial (DNG). In this paper, the correct sign of the permittivity and permeability of an equivalent stationary media, for each TE and TM modes and for both low and high dielectric velocities are investigated and it is shown that this medium acts as a DNG material over specific frequency ranges.
Author(s): A. Jafargholi, A. Jafargholi
File Type: Journal Paper
Issue:Volume: 27      Number: 11      Year: 2012
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Title: Ultra-wideband Flexible Implantable Antenna for Wireless Capsule Endoscopy System with Performance Improvement
Abstract: The implantable antenna is an important part of the wireless capsule endoscopy (WCE) system to achieve wireless communication. This paper designed an ultra-wideband flexible implantable antenna for wireless capsule endoscopy system. With a very wide bandwidth, the antenna can completely cover the industrial, scientific, and medical frequency bands (ISM, 2.4-2.48 GHz) and Wireless Medical Telemetry Service (WMTS, 1.395-1.4 GHz). The expanded size of the proposed antenna is 18mm× 10mm× 0.1mm. The conformal technology of the antenna has further reduced the space of the system and achieved miniaturization. The capsule antenna in this paper is a compact planar monopole antenna fed by a coplanar waveguide, and it uses a flexible material as a dielectric substrate to achieve the conformal shape of the antenna. U-shaped ground branch (UGB) and a loaded split ring resonator (SRR) structure were used to further improve the antenna performance. Simulation and measurement results were basically the same. On the premise of radiation safety and miniaturization of the antenna, the ultra-wideband operation of the antenna was realized. This antenna design provided reference value for the design and application of the capsule antenna.
Author(s): Y. Feng, P. Chen, S. Pan, G. Li
File Type: Journal Paper
Issue:Volume: 36      Number: 6      Year: 2021
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Title: Ultra Wideband Microwave Ten-Port Reflectometer
Abstract: This paper describes and simulates the Ultra Wideband (UWB) Ten-Port Reflectometer (TPR). It is based on the concept of well-known sixport structure so that numbers of measuring ports are increased to eight in order to improve reliability and accuracy as well. This article presents UWB (2 GHz to 12 GHz) reflectometer using Rectangular Waveguide (RWG). It is proved that increasing numbers of measuring ports leads to improving accuracy and reliability of structure so that each port with corresponding port help to make wideband reflectometer as well as having reliable and robust structure. This prototype of ten-port reflectometer is simulated by Agilent ADS and using RWG that has more bandwidth, less loss and high Q-factor than other common transmission lines, say microstrip, SIW and CPW.
Author(s): A. Askarian, G. Moradi
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Tunneling of Spoof Surface Plasmon Polaritons through Effective Epsilon-Near-Zero Material
File Type: Conference Paper
Issue:Volume: 2-P2-F Metamaterials      Number:      Year: 2017
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Title: Tuning of Waveguide Bandstop Filter Properties by Changing the Physical Dimensions of Metamaterial Unit Cell
File Type: Conference Paper
Issue:Volume: Modeling of Metamaterials and Transformation Based Devices      Number:      Year: 2011
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Title: Tunable Terahertz Plasmon-Induced Transparency in Resonator-Coupled Dirac Semimetal Waveguides
Abstract: The bulk Dirac semimetal (BDS) is an interesting material, similar to graphene, which can dynamically adjust its optical properties via a variation in its Fermi energy or electrical voltage. In this work, a BDS-based plasmonic device, which enables tunable terahertz plasmon-induced transparency, was proposed and designed. By using the finite element method, the surface plasmon polariton and plasmon-induced transparency of this device were systematically investigated. The results demonstrate that the plasmoninduced transparency of such device can be dynamically tuned by varying its Fermi energy. When the Fermi energy changes from 55 meV to 95 meV, the maximum group delay time of the device increases from 13.2 ps to 21 ps. In the case of a cascading device, the maximum group delay time can be further pushed up to 44.57 ps. The influence of the ambient refractive index on the optical properties of the proposed device was also considered and investigated.
Author(s): D. Wang, J. Yang, W. Wang, L. Yuan, X. Li
File Type: Journal Paper
Issue:Volume: 36      Number: 6      Year: 2021
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Title: Tunable Bandstop Filter Based on Split Ring Resonators Loaded Coplanar Waveguide
Abstract: In this paper, a novel electrical tunable bandstop filter based on coplanar waveguide (CPW) loaded with split ring resonators (SRRs) is proposed. The unit cell of the bandstop filter is formed by etching single SRR on the CPW back substrate side, and the SRRs can be excited by the CPW slot’s magnetic field. Lumped equivalent circuit models are developed to analyze the frequency responses, and it shows that by loading the common cathode varactor diodes at the split region of the SRR outer ring, the resonant frequency of the bandstop filter can be electronically adjusted by tuning the reverse voltage of the varactor diodes. The prototype with overall size of 26.6 mm ? 50 mm ? 0.508 mm was designed and fabricated to validate the proposed structure. The measured tunable resonant frequency of the fabricated bandstop filter is from 2.19 GHz to 2.31 GHz while a reverse bias voltage is varying from 0 V to 30 V. It also shows that the -10 dB bandwidth is less than 45 MHz.
Author(s): Q. Xiang, Q. Feng, X. Huang
File Type: Journal Paper
Issue:Volume: 28      Number: 7      Year: 2013
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Title: Triple-Band GCPW Rectifier for Harvesting EM Energy
File Type: Conference Paper
Issue:Volume: 3-3-D Wireless Power Transfer and Harvesting      Number:      Year: 2017
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Title: Transmission Bandgap of a Two-dimensional Coaxial Bragg Structure with Hybrid Filling Media
File Type: Conference Paper
Issue:Volume: 2-2-C Novel Electromagnetic Metamaterials and Their Applications      Number:      Year: 2017
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Title: TRANSMISSION AND REFLECTION CHARACTERISTICS OF A CLASS OF MODIFIED COPLANAR WAVEGUIDE STRUCTURES
Abstract: In this paper, several geometries of a class of grounded coplanar waveguide (GCPW) are investigated using the finite difference time domain (FDTD) method, and their losses are computed. A uniform grounded coplanar waveguide (GCPW) structure is used as a reference case for the other non-uniform geometries. First, this reference case is studied. For this case, four geometries are proposed to study the transmission and loss effect of replacing parts of the dielectric substrate with free space. Afterwards, two new geometries are simulated to study the effect of introducing a neck and a gap in the microstrip feeding line, with and without a bridge that connects the two parts of the microstrip feeding line separated with the gap. The effect of adding a PEC cap above the microstrip feeding line, and connecting the two side ground planes, is also studied. The conductor attenuation is studied for the basic GCPW geometry. The power losses are also calculated for the uniform geometries. The line impedance is calculated for all geometries at several points.
Author(s): Abdelnasser. A. Eldek, Atef. Z. Elsherbeni, Charles. E. Smith, Abdelnasser. A. Eldek, Atef. Z. Elsherbeni, Charles. E. Smith
File Type: Journal Paper
Issue:Volume: 17      Number: 2      Year: 2002
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Title: THz Square Cross Section Smooth Spline Horns as a Competitive Alternative to Corrugated Horns
File Type: Conference Paper
Issue:Volume: S09 Advances in Electromagnetic Modeling by WIPL-D - I      Number:      Year: 2020
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Title: Three-Way Substrate Integrated Waveguide (SIW) Power Divider Design
File Type: Conference Paper
Issue:Volume: S48 Waveguides and Guided Structures II      Number:      Year: 2016
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Title: Three-bit Unit-cell with Low Profile for X-Band Linearly Polarized Transmitarrays
Abstract: In this paper, we present a three-bit phase resolution and low profile unit-cell structure for X-band passive transmitarrays. The unit-cell is implemented using four metallic layers printed on two substrates separated by an air gap. The phase shift is achieved by a combination between current flow modification on middle layers and the variation of the size of path elements. Eight unit-cells are optimized to provide eight phase states with a step of 45°. Experimental results are conducted by using WR-90 waveguide to validate the design. These eight unit-cells cover a wide -3 dB transmission bandwidth of 15% and exhibit a low thickness of 0.18λ0.
Author(s): B. D. Nguyen, M. T. Nguyen
File Type: Journal Paper
Issue:Volume: 34      Number: 9      Year: 2019
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Title: Theoretical and Experimental Analysis of Rectangular Waveguides with Isotropic Chiral Media
File Type: Conference Paper
Issue:Volume: Poster Sessions 2      Number:      Year: 2007
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Title: The Use of Offset Coupled Microstrip Combline Filters for IF Filters Requiring High Selectivity
File Type: Conference Paper
Issue:Volume: EM Simulations Using Sonnet - II      Number:      Year: 2010
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Title: The Time-Bandwidth Limit in Optical Nanostructures and Its Relation to Nonreciprocity
File Type: Conference Paper
Issue:Volume: S08 Design, Analysis and Applications of EM Metasurfaces I      Number:      Year: 2018
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Title: The Temperature Compensation for TE011 Mode Resonator with Bimetal Material
Abstract: This paper proposes a temperature compensation design for TE011 mode resonator based on multiphysics analysis. The relationship between structure and electrical performance of circular waveguide resonator is specifically analyzed. Furthermore, a novel temperature compensation structure with bimetal material is proposed by using multiphysics analysis. The proposed TE011 mode resonator is fabricated and tested to verify the design method. The temperature drift coefficient of the compensated TE011 mode resonator can be dramatically reduced from 21.387 ppm/°C to 0.93ppm/°C.
Author(s): Q. Wu, J. Zhang, Y. Yang, X. Shi
File Type: Journal Paper
Issue:Volume: 34      Number: 7      Year: 2019
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Title: The Substrate Integrated Waveguide T-junction Power Divider with Arbitrary Power Dividing Ratio
Abstract: An X-band H-plane wideband substrate- integrated waveguide (SIW) T-junction power divider with unequal-power-division ratio is presented. Several inductive posts are used to have arbitrary power dividing ratio and also to control the phase difference. The position and diameter of these posts tune the power-split ratio and the phase difference in whole bandwidth. Parametric studies have been done to choose the best positions and diameters to get better results. Two different prototypes have been verified the proposed technique. They are designed and fabricated at a center frequency of 11 GHz. The measured input impedance bandwidths are 54% for ?out =3 dB and 45% for ?out =6 dB respectively.
Author(s): A. Piroutiniya, P. Mohammadi
File Type: Journal Paper
Issue:Volume: 31      Number: 4      Year: 2016
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Title: The Multiresolution Frequency Domain Method for the Efficient Analysis of Ferrite Loaded Waveguides
File Type: Conference Paper
Issue:Volume: Finite Difference Methods: Recent Developments and Applications      Number:      Year: 2012
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Title: The Design of Planar Slot Arrays Revisited
Abstract: Design procedures for planar waveguide slot arrays have been known and used for years, but the inexperienced designer is often faced with a number of practical problems when trying to implement them, especially in the case of larger arrays consisting of sub-arrays. Some helpful hints concerning the numerical implementation are provided. These include an effective procedure to avoid the necessity of good initial guesses for the unknown dimensions and recommendations for the subdivision of the nonlinear equations into smaller groups. Other practical aspects which are not explicitly defined elsewhere in the literature, are also addressed.
Author(s): J.C. Coetzee, J. Joubert, J.C. Coetzee, J. Joubert
File Type: Journal Paper
Issue:Volume: 15      Number: 1      Year: 2000
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Title: The Design of a High Gain Dual-Polarized Quad-Ridged Circular Horn Antenna for Wideband EMC Test Applications
Abstract: This paper presents the design of a high gain broadband quadruple-ridged circular horn antenna for Electromagnetic Compatibility (EMC) testing. The proposed antenna contains a wideband feed structure as a transition between coaxial line and quad-ridged circular waveguide behind the conical horn antenna. The wideband matching between impedances at the apertures of the feed and the horn is achieved with a tapering at the flare section along the horn length, which is obtained after a detailed investigation of various tapering profiles. The antenna is designed to operate in horizontal and vertical polarizations (dual linear polarization) simultaneously in EMC tests. This implementation is found to present a return loss greater than 10 dB, isolation level higher than 28 dB, high-gain (minimum 13.6 dBi) and low-gain variation of 4.5 dBi within the frequency range of 1-6.75 GHz (6.75:1 bandwidth) at both polarizations, which is a desired feature in radiated emission and immunity tests.
Author(s): B. Solak, M. Secmen, A. Tekin
File Type: Journal Paper
Issue:Volume: 33      Number: 9      Year: 2018
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Title: The Design of 276 GHz Triple-Push VCO Based on 65nm CMOS Process Using Slow-Wave Effect
File Type: Conference Paper
Issue:Volume: 4-P4-C THz Antenna, Circuit and System      Number:      Year: 2017
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Title: Suppression of Anisotropic Birefringence in a Rectangular Waveguide
File Type: Conference Paper
Issue:Volume: S45 Electromagnetic Methods for Devices and Applications I      Number:      Year: 2018
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Title: Superformula-Based Compact UWB CPW-Fed-Patch Antenna With and Without Dual Frequency Notches
Abstract: This paper presents two new designs of UWB coplanar waveguide (CPW)-fed-patch antennas operating in the FCC frequency band (3.1-10.6 GHz). The first design uses the superformula to produce a circular patch with sawtooth-like circumference. As compared to a regular circular patch antenna whose diameter is 25 mm, the proposed circular patch has a smaller diameter of 18.2 mm. Moreover, the proposed antenna covers the entire FCC band unlike a regular circular patch of the same radius. The second design introduces two frequency notches at 3.3-3.8 GHz (WiMAX) and 5-5.9 GHz (WLAN) using two arc shaped circular slots etched on the circular patch and a split-ring resonator (SRR) that is placed on the opposite side of the substrate. Measurements and simulations using HFSS show that the return loss is better than 10 dB across the band except at the two notch locations in Design II. Results are also presented for the radiation pattern and peak gain of both designs. Each of the proposed antennas has a compact size of 24 mm x 19 mm on a 1.5 mm Rogers Substrate (epsilon r=3.85).
Author(s): A. A. Omar, S. Naser, M. I. Hussein, N. I. Dib, M. W. Rashad
File Type: Journal Paper
Issue:Volume: 32      Number: 11      Year: 2017
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Title: Substrate Integrated Waveguide-Fed Tapered Slot Antenna With Smooth Performance Characteristics Over an Ultra-Wide Bandwidth
Abstract: We present an ultra-wide extended Kband (18 GHz – 30 GHz) planar linear tapered slot antenna (LTSA) design. From a parametric study involving eight designs, the best compromise LTSA is selected in terms of flattest gain and beam width and most symmetric beam width. The design is antipodal with alumina (?r = 10) substrate and fed with substrate integrated waveguide (SIW). Regular corrugations improve cross-polarization, input return loss, and gain. Numerical simulations use finite element analysis and time domain finite integration technique field solvers. The resulting design has half power beam widths (HPBW) of only ± 3.2° and ± 2.5° variation in frequency in the E- and H-planes, respectively. Cross-polarization levels at boresight are 35.7 dB at 18 GHz and 17.4 dB at 30 GHz, return loss is better than -11.7 dB and gain is 9.23 dB with ± 0.40 dB variation with frequency. Alternatively, for imaging systems requiring efficient illumination of a reflector or focusing elements, a second resulting design shows near-perfect beam symmetry with HPBWE/HPBWH = 0.91. These two LTSAs are good candidates for dual-polarization focal plane array feed applications in astronomy imaging.
Author(s): L. S. Locke, J. Bornemann, S. Claude
File Type: Journal Paper
Issue:Volume: 28      Number: 5      Year: 2013
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Title: Substrate Integrated Waveguide Microwave Filter Tuning Through Variable-Fidelity Feature Space Optimization
File Type: Conference Paper
Issue:Volume: EM-Simulation-Driven Design: Modeling and Optimization      Number:      Year: 2014
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Title: Study, Design and Fabrication of a CPW Fed Compact Monopole Antenna with Circular Polarization for Ultra Wide Band Systems Application
Abstract: A compact circularly polarized square slot antenna (CPSSA) is presented in this paper, which is appropriate for UWB applications requiring high data rate transmission. This antenna operates across 2.8 GHz to 10.8 GHz with an impedance bandwidth (IBW) of 117.6% for VSWR less than or equal to 2. The antenna consists of a trapezoidal shaped radiation patch which is fed through a coplanar waveguide (CPW) and includes two inverted L-shaped ground arms at the two opposite corners of the slot to excite two orthogonal resonant modes for circular-polarization (CP) radiation. Furthermore, two square slits at the two other opposite corners of the slot are applied to enhance its IBW. The antenna exhibits CP bandwidth of 50.5% across 3.7 GHz-6.2 GHz, which is suitable for WLAN, WiMAX and C-bands. In addition, the antenna has a considerably compact volume of 25×25×0.8 mm3. The measured and simulated results confirm the usefulness of the antenna for practical applications.
Author(s): M. Shokri, S. Asiaban, A. Amiri
File Type: Journal Paper
Issue:Volume: 32      Number: 9      Year: 2017
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Title: Structural Optimization of an Optical 90 Degree Hybrid Based on a Weaklyguided 4x4 Multimode Interference Coupler Using a Parallelized Real-coded Micro-genetic Algorithm
Abstract: The optimal design of a 4x4 multimode interference (MMI) coupler as an optical 90° hybrid based on a weakly-guided optical waveguide was considered. Seven geometrical parameters of a 4x4 MMI coupler were optimized by a real-coded micro-genetic algorithm, and parallelized using a message-passing interface. The beam-propagation method was used to evaluate the fitness of the MMI coupler in the optimization process. The optimized 4x4 MMI coupler showed a common-mode rejection ratio greater than 28.9 dBe and a phase error less than 2.52° across a wavelength range of 1520 to 1580 nm, which satisfied typical system requirements. The optimization process was executed on a Beowulf-style cluster comprising five identical PCs, and its parallel efficiency was 0.78.
Author(s): T. Yasui, J. Sugisaka, K. Hirayama
File Type: Journal Paper
Issue:Volume: 36      Number: 5      Year: 2021
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Title: Spurious Solutions in Fast Frequency Sweeps
File Type: Conference Paper
Issue:Volume: In Tribute To Dr. Zoltan Cendes      Number:      Year: 2012
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Title: Spoof Surface Plasmons on the Dielectric-loaded Doubly-corrugated Grating for Terahertz Applications
File Type: Conference Paper
Issue:Volume: 1-SP-2 Electromagnetic Characteristics of Complex Media Simulated by Time Domain Method I      Number:      Year: 2018
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Title: Space-Mapping-Enhanced Kriging Surrogates for Accurate Modeling of Microwave Structures
File Type: Conference Paper
Issue:Volume: Optimization Methods for EM Applications      Number:      Year: 2012
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Title: Space-Frequency Domain Iterative Method for Modes Analysis of Planar Waveguides
Abstract: We describe a space-frequency domain iterative algorithm to analyze the modes of planar optical waveguides. The one dimensional Maxwell equation was transformed into space-frequency domain by Fourier transform, and became an integral equation which could be solved by an iterative method. For any refractive index profiles, the effective index and mode field distribution are given simultaneously. The numerical result shows that this method is accurate and flexible for planar optical waveguides with any structure.
Author(s): L. Bingxin, Z. Baorong
File Type: Journal Paper
Issue:Volume: 30      Number: 8      Year: 2015
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Title: Space Use Radial Line Slot Antenna with Honeycomb Structure
File Type: Conference Paper
Issue:Volume: Student Paper Competition      Number:      Year: 2007
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Title: SOME EXPERIENCES IN USING NEC2 TO SIMULATE RADIATION FROM SLOTS ON CYLINDERS
Abstract: A numerical method based on use of the NEC2 code has been used to study radiation from a slot in the surface of a conducting cylinder and the results used in a comparison with the eigenfunction series solu-tion. The two cases of an axial and circumferential slot have been taken as representative between them of the more general case of an inclined slot. In the case of a circumferential slot, truncation of the cylin-der to finite length has been found in all cases to lead to numerical and analytic results which are in poor agreement and this has been accounted for with an argument based on the geometrical theory of dif-fraction. However this alone is not enough to explain what is observed with axial slots where, for small cyl-inders, agreement of the two approaches is good but fails for larger cylinders. It is postulated that this is due to excitation of waveguide modes on the inside of the larger cylinders and the result confirmed by clos-ing the ends of the cylinder in the NEC2 model with a system of radial wires, when agreement is again re-stored.
Author(s): S. H. H. Lim, H. E. Green, C. E. Brander, S. H. H. Lim, H. E. Green, C. E. Brander
File Type: Journal Paper
Issue:Volume: 13      Number: 1      Year: 1998
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Title: Slotted Waveguide Transitions for Spatial Power Combining
File Type: Conference Paper
Issue:Volume: Posters Session 2      Number:      Year: 2003
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Title: Slotted Coaxial Line and Associated Measurement System for Determination of Dielectric Properties of Gas Plasma
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D Software      Number:      Year: 2007
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Title: Size-Reduced Bandpass Filter Using HMSIW and Modified U-Shaped DGS Slot-Pairs
File Type: Conference Paper
Issue:Volume: S18 Electromagnetic Metamaterials and Metasurfaces      Number:      Year: 2015
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Title: SIW Rotman Lens with Planar Slot Array Antenna at Ku-band
Abstract: A multi-beam antenna, which is the combination of a Rotman lens and a planar slot array antenna, is designed in this paper. The lens and the slot array are designed for 15.5 to 16.5 GHz frequency range and implemented in the same substrate using SIW structure. The Rotman lens with 7 input ports and 7 output ports are connected to a planar slotted array antenna with 7 waveguides. This multi-beam antenna consists of seven beams at angles of 0°, ±10°, ±20° and ±30° symmetrically. This antenna is designed for terrestrial and satellite applications, where the low cost, low profile and light multi-beam antennas are needed. Simulated and measured results show that the amplitude and phase distributions and scattering parameters of the antenna are in good agreement. In addition, the SLL, HPBW, main beam direction and cross polarization levels of all the radiation patterns are desirable.
Author(s): S. A. Hosseini, Z. H. Firouzeh, M. Maddahali
File Type: Journal Paper
Issue:Volume: 32      Number: 6      Year: 2017
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Title: SIW like Bull-Eye Antenna
File Type: Conference Paper
Issue:Volume: S04 Printed, Flexible and Reconfigurable Antenna Implementations      Number:      Year: 2020
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Title: SIW Circularly-Polarized Filtering Antenna
File Type: Conference Paper
Issue:Volume: 1-P1-A Student Paper Contest      Number:      Year: 2017
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Title: Single-, Dual- and Wide-Band Frequency-Reconfigurable Antenna with Annular Ring Slots
Abstract: This paper presents a frequency reconfigurable antenna enabled using a pair of annular ring slots on a coplanar waveguide (CPW) ground plane. Its initial wideband operation mode from 3 GHz to 6 GHz can be reconfigured into six additional modes: a dual–band mode and five single-band modes, with minimum reflection coefficients (S11) of -10 dB. For demonstration and proof-of-concept purposes, metal switches have been used to represent the switches in simulations and measurements. The ON state is emulated using shorted metal switches, whereas the OFF state is emulated using an open. Good agreements are indicated for simulated and measured S11 and radiation patterns.
Author(s): M. C. Lim, S. K. A. Rahim, M. R. Hamid, P. J. Soh, M. I. Sabran, A. A. Eteng, M. R. Ramli
File Type: Journal Paper
Issue:Volume: 32      Number: 11      Year: 2017
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Title: Single Mode Field Derivation and Simulation of a Dual Ridged Waveguide Dual Probe
File Type: Conference Paper
Issue:Volume: S21 EM-Simulation-Driven Design: Modeling and Optmization      Number:      Year: 2015
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Title: Simulation-Driven Design of Microstrip-to-CPW Transitions Using Variable-Fidelity EM Models
File Type: Conference Paper
Issue:Volume: Electromagnetic-Simulation-Driven-Design: Modeling and Optimization      Number:      Year: 2011
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Title: Simulation Analysis of Cross Polarization Property of Waveguide Slot
File Type: Conference Paper
Issue:Volume: 5-P-1 Poster      Number:      Year: 2018
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Title: Shift-Inverse Technique in TLM-ROM
File Type: Conference Paper
Issue:Volume: Recent Advances in Time Domain Modeling Techniques      Number:      Year: 2004
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Title: Shielding Effectiveness of Three Dimensional Gratings using the Periodic FDTD Technique and CPML Absorbing Boundary Condition
File Type: Conference Paper
Issue:Volume: Special Session: Electromagnetic Modeling by WIPL-D      Number:      Year: 2005
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Title: Sensitivity Analysis of the Orthorhombic Design Parameters in the Artificially Biaxially Dielectric Crystal
Abstract: A full-wave modeling and simulation analysis method is presented for performing sensitivity analysis of artificial uniaxial and biaxial crystals previously reported for study with waveguide measurement systems. Small occlusions were machined into bulk dielectric material to impose effectively biaxial material properties. Here, the primary design parameters for orthorhombic occlusions are presented. Using multivariate parameter estimation, the effective material properties are characterized in a way that is equivalent to waveguide measurement methods. The advantage in using full-wave simulation allows investigation beyond measurement and fabrication capabilities, but is still limited because of the mesh size needed to model the fine geometric sizes of the occlusions in the crystal. The analysis shows that the effects of the primary design parameters on anisotropy can achieve 2-3 dB of axial difference for the biaxially diectric crystal. Although, only the dielectric case is presented, the multivariate estimation method used to estimate the material parameters is applicable for characterizing lossy and magnetic materials.
Author(s): J. Brand, M. A. Saville
File Type: Journal Paper
Issue:Volume: 30      Number: 10      Year: 2015
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Title: Scattering by Closed and Unclosed Metallic Rings in a Circular Waveguide
File Type: Conference Paper
Issue:Volume: Poster Session      Number:      Year: 2006
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Title: Scan Blindness Elimination Using Composite Defected Ground Structures and Edge-coupled Split Ring Resonators
Abstract: A novel compact composite structure, composed of double-U shaped defected ground structure (DGS) and edge-coupled split ring resonator (E-SRR), is presented in this paper. The composite structure is integrated into microstrip array to reduce the interelement mutual coupling, with the aim to eliminate the scan blindness and improve the scanning performance. The three kinds of two-element arrays (without composite structure, with only DGS and with composite structure) are thoroughly simulated, measured, and compared. The results show that, the reduction in mutual coupling of 11 dB between elements in E-plane is obtained with the use of composite structure. It is worth mentioning that, approximately 2dB gain improvement and 2.4dB side lobe suppression are both attained, in comparison with the array with only DGSs. Finally, the scan properties of three kinds of infinite microstrip phased arrays are studied by the waveguide simulator method. The results indicate that the scan blindness in an infinite microstrip phased array can be well eliminated by virtue of the effect of the proposed composite structures, in accordance with results obtained by active patterns of the centre element in 9×5 array.
Author(s): M. C. Tang, S. Xiao, C. J. Li, C. Wei, B. Wang
File Type: Journal Paper
Issue:Volume: 26      Number: 7      Year: 2011
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Title: Role of Surface Geometric Patterns and Parameters in the Dispersion Relations of Spoof Surface Plasmon Polaritons at Microwave Frequency
Abstract: Spoof surface plasmon polaritons (SSPPs) can be excited using geometric shapes on conducting surfaces in microwave (MW) regime. They are eminent as compared to the conventional microstrip (MS) transmission lines, due to their better efficiency and compactness in high density and high-speed circuitry. In this work, we compare normalized dispersion curves (DCs) of different groove shapes engineered on the planar metallic strip with the variation of geometric parameters of the structure, which are obtained by Eigen-mode solver of ANSYS’s HFSS. It is found the dispersion characteristics are determined by the shape and the asymptotic frequency can finely be tuned through the geometric parameters. All DCs deviate further from the light line indicating slow propagation of SSPPS. The performance of rectangular grooves is clearly outstanding; however, the circular grooves behave comparably better than Vee-groove. Further, a low pass plasmonic filter has been proposed with semicircular gradient subwavelength grooves designed on a planar metallic strip with transition sections to match both the impedance and momentum of MS line and the plasmonic waveguide. Results of S-parameters and magnitude of electric field distributions show excellent transmission efficiency from fast guided wave to slow SSPPs. It is also observed that the confinement of such surface waves is dependent on the geometric parameters which can be useful in plasmonic structure engineering and fine-tuning the cutoff frequencies, hence posing a new prospect for advanced plasmonic integrated devices and circuits.
Author(s): R. S. Anwar, L. Mao, H. Ning
File Type: Journal Paper
Issue:Volume: 34      Number: 1      Year: 2019
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Title: Robust and Efficient Model-Order Reduction for Lossless Microwave Structures Using the Impedance Formulation of the Finite Element Method
File Type: Conference Paper
Issue:Volume: S18 Computational Electromagnetics Advanced Algorithms and Emerging Applications I      Number:      Year: 2017
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Title: RF Magnetic Field Profiling with a Dielectric Bore Lining for Traveling Waves in a 3-T MRI Scanner: A Computational Study
Abstract: Traveling-wave magnetic resonance imaging (MRI) can be advantageous over the classical, quasistatic or near-field MRI. However, it is restricted to ultra-high static magnetic fields in the scanner and the correspondingly high RF excitation magnetic field frequencies due to fundamental constraints in cutoff frequencies of the MRI bore, considered as a waveguide. Through a computational study, we propose translating traveling-wave ideas to a 3-tesla scanner, where the RF magnetic field frequency is 127.8 MHz, using a highpermittivity dielectric layer (lining) that is built into the bore. With the lining, we can achieve traveling-wave modes inside the imaging phantoms even at 3 T, where this is generally not possible. We present results obtained using the higher order method of moments in the surface integral equation formulation, previously established as an efficient, accurate, and reliable technique for modeling of RF fields in MRI applications. Our simulations of a simple circularly polarized RF probe and dielectric lining give rise to a considerably uniform circularly polarized RF magnetic field inside phantoms in the clinical scanner.
Author(s): M. M. Ilic, A. A. Tonyushkin, P. S. Athalye, N. J. Sekeljic, A. J.M. Kiruluta, B. M. Notaros
File Type: Journal Paper
Issue:Volume: 35      Number: 3      Year: 2020
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Title: Response Sensitivity Analysis with Frequency-Domain Full-Wave Electromagnetic Solvers
File Type: Conference Paper
Issue:Volume: Optimization and Solution of Complex EM problems      Number:      Year: 2004
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Title: Research of Medical and Industrial Applications of Microwaves Supported by SEMCAD
File Type: Conference Paper
Issue:Volume: SEMCAD X: Recent Modeling Advances for Virtual Prototyping      Number:      Year: 2007
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Title: Reflection compensation scheme for the efficient and accurate computation of waveguide discontinuities in photonic crystals
Abstract: Abstract—We presented a novel method for the accurate and efficient computation of the reflection and transmission coefficients of waveguide discontinuities within planar photonic crystals (PhCs). This method proposes a novel kind of field source that optimally excites the dominant waveguide mode and mimics procedures that are typically used for the measurement of reflection coefficients. This technique may be applied to arbitrary field simulators working in the frequency domain. The presented reflection compensation scheme is elucidated along the Method of Auxiliary Sources (MAS). In order to verify the results, we compare two test cases with the rigorous connection technique provided by the Multiple Multipole Method (MMP).
Author(s): D. Karkashadze, R. Zaridze , A. Bijamov, D. Karkashadze, R. Zaridze , A. Bijamov
File Type: Journal Paper
Issue:Volume: 19      Number: 1      Year: 2004
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Title: Reducing Power Coupling Loss between Laser Diodes and Planar Optical Waveguides by Using Tapers
File Type: Conference Paper
Issue:Volume: Guided Waves in Non-Standard Media      Number:      Year: 2008
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Title: Reconfigurable 2×1 CPW-Fed Rectangular Slot Antenna Array (RSAA) Based on Graphene for Wireless Communications
Abstract: This article presents a 2×1 CPW ultra wideband rectangular slot antenna array (UWB-RSAA) with a modified circular slot shape to support a high data rate for wireless communications applications. The proposed antenna array dimensions are 0.7λo×0.8λo×0.064λo at the resonant frequency 1.8 GHz. It is fabricated on Rogers RO4003 substrate and fed by using a coplanar waveguide (CPW). A graphene layer is added on one side of the substrate to realize frequency reconfigurability and improve the array gain. The proposed array acquires -10 dB impedance bandwidth of the RSAA that extends from 1.7 GHz to 2.6 GHz, from 3.2 to 3.8 GHz, and from 5.2 GHz to 7 GHz. The proposed array achieved a realized peak gain of 7.5 dBi at 6.5 GHz at 0 Volt bias with an average gain of 4.5 dBi over the operating band. When the graphene bias is increased to 20 Volt, the antenna bandwidth extends from 1 GHz to 4 GHz and from 5 to 7 GHz with a peak gain of 14 dBi at 3.5 GHz and an average gain of 7.5 dBi. The linearly polarized operation of the proposed array over the operating bands makes it suitable for short-range wireless communications .
Author(s): D. M. Elsheakh, O. M. Dardeer
File Type: Journal Paper
Issue:Volume: 36      Number: 6      Year: 2021
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Title: Recent extensions in FEKO: Parallel MLFMM and waveguide excitations
File Type: Conference Paper
Issue:Volume: FEKO Modeling and Analysis - 1      Number:      Year: 2006
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Title: Recent Advances in FDTD Modeling of Electromagnetic Wave Propagation in the Ionosphere
Abstract: Finite-Difference Time-Domain (FDTD) modeling of electromagnetic wave propagation in the Earth-ionosphere waveguide has gained significant interest over the past two decades. Initially, FDTD modeling capabilities were largely limited to two-dimensional models assuming a plasma ionosphere (but incapable of accounting for Faraday rotation), or to threedimensional global models assuming a simple, isotropic conductivity profile ionosphere. Two algorithm developments have recently advanced the state-of-the-art in electromagnetic wave calculation capabilities in the ionosphere: (1) A new, three-dimensional efficient FDTD magnetized plasma model. (2) A Stochastic FDTD (S-FDTD) model of magnetized ionospheric plasma. The first capability permits longer-distance, higher frequency and higher altitude propagation studies by greatly reducing the memory requirements and simulation time relative to previous plasma models. The second capability introduces for the first time a way of solving for not only mean electromagnetic field values, but also their variance. This paper provides an overview of these two recent advances.
Author(s): B. T. Nguyen, A. Samimi, J. J. Simpson
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Recent Advances for the Full-Wave Analysis and Design of Waveguide Filters for Space Applications
File Type: Conference Paper
Issue:Volume: Efficient Microwave Subsystem Design and Optimization      Number:      Year: 2010
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Title: Recent Advance in Neuro-Transfer Function-Assisted Yield-Driven EM Optimization
File Type: Conference Paper
Issue:Volume: S40 Advanced Optimization of Electromagnetic Structures - III      Number:      Year: 2021
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Title: Realization of a Sub-harmonic Mixer with a Substrate Integrated Waveguide Filter
File Type: Conference Paper
Issue:Volume: Design and Analysis of Advanced Circuit Architectures      Number:      Year: 2005
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Title: Ray Tracing Using Shooting-Bouncing Technique to Model Mine Tunnels: Theory and Verification for a PEC Waveguide
Abstract: We present a shooting-bouncing approach to ray-tracing as applied to signal propagation modeling in electrically large waveguides, such as underground mine tunnels at wireless communication frequencies. The method is verified for a dominantmode rectangular metallic waveguide excited by a dipole antenna.
Author(s): B. A. Troksa, C. L. Key, F. B. Kunkel, S. V. Savic, M. M. Ilic, B. M. Notaros
File Type: Journal Paper
Issue:Volume: 34      Number: 2      Year: 2019
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Title: Ray Tracing Using Shooting-Bouncing Technique to Model Mine Tunnels: Theory and Verification for a PEC Waveguide
File Type: Conference Paper
Issue:Volume: S14 Numerical Methods for Analysis, Design and Measurement of Antennas I      Number:      Year: 2018
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Title: Protection of Computer Enclosure against Coupled Electromagnetic Interference
Abstract: In this paper some suggested protection methods is proposed to improve the shielding effectiveness of computer enclosures. Slots and holes on the computer enclosure are divided into five types, and the coupled electromagnetic interference (EMI) into the enclosure is computed using the finite-difference time-domain (FDTD) method when each type slot exists. From comparison of both time domain electric field waveform and field distribution in the enclosure, vent array, joint laps, CD-ROM and display are found to be the main ways that the EMI penetrated into the enclosure. To improve the protection of the enclosure, waveguide window is used to replace vent array. Additionally, rivet number is increased, depth of the joint laps is increased and conductive gaskets are filled into the joint laps. From numerical analyses, it can be demonstrated that the suggested methods are efficient to improve shielding effectiveness of the computer enclosure. Some suggested methods are also proposed for the CD-ROM and display protection.
Author(s): R. Xiong, W. Yang, H.-L. Chen, Y.-T. Duan
File Type: Journal Paper
Issue:Volume: 33      Number: 11      Year: 2018
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Title: PROPAGATION OF VLF RADIATION IN THE EARTH-IONOSPHERE WAVEGUIDE EXCITED BY AN AIRBORNE DUAL TRAILING WIRE ANTENNA
Abstract: Field strength variations produced by an orbiting aircraft dual trailing wire VLF transmitting antenna are investigated. The towplane is assumed to be executing a circular orbit at a constant altitude and speed. A steady-state mechanical model is adopted for determination of the shape of the dual trailing wire antenna. The exact current distribution on this antenna is calculated using the Numerical Electromagnetics Code (NEC) which is based on a method of moments solution of the Electric Field Integral Equation (EFIE). A propagation code developed at the Naval Ocean Systems Center (NOSC) called TWIRE has been modified to be used in conjunction with NEC. This modified version of TWIRE has been called TWIRENEC. The TWIRENEC code uses the current distribution information provided by NEC to determine the dipole moments for a segmented antenna. The wire segmentation geometry and corresponding dipole moments are then used to calculate the electric field strength as a function of distance and azimuth in the earth-ionosphere waveguide. The waveguide can be considered as either horizontally homogeneous or inhomogeneous. It is demonstrated that the periodic variations in field intensity resulting from an orbiting transmitter are a function of receiver position. These periodic variations can range from a small fraction of a dB to several dB depending upon the location of the receiver with respect to the transmitter. A point dipole approximation of the dual trailing wire antenna is suggested for use in the study of VLF radiation excited by an orbiting antenna in the presence of wind shear. The point dipole approximation is applied to estimate the field strength variations caused by a yo-yo oscillation of the transmitting antenna as it orbits. These yo-yo oscillations are characterized in terms of the change in verticality of the point dipole which occurs over one complete orbit. [Vol. 8, No. 2 (1993), pp 72-92]
Author(s): D.H. Werner, J.K. Breakall, R. J. Lunnen, D.H. Werner, J.K. Breakall, R. J. Lunnen
File Type: Journal Paper
Issue:Volume: 8      Number: 2      Year: 1993
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Title: Propagation Mode in a V-shaped Silicon Groove Waveguide Embedded with Metal Nanowires
File Type: Conference Paper
Issue:Volume: 9-P-2 Poster      Number:      Year: 2018
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Title: Powering Sensors in IoT System by Using Compact Seven Band PIFA Rectenna
Abstract: A compact seven band coplanar waveguide fed planar inverted F antenna (PIFA) is presented. The proposed antenna is designed to harvest the ambient radio frequency energy at GSM 900, GSM 1800, LTE band 11 and 7, UMTS 2100, Wi-Fi 2.4, LTE and WIMAX 5.2. The antenna is simulated using 3D electromagnetic simulators CST and HFSS. Moreover, the antenna is fabricated and it is used to measure the indoor RF spectrum in Egypt. A simple AC to DC converter unit is designed by using HSMS 2850 Schottky diode to convert the collected RF energy to DC energy. The antenna and the AC to DC converter are integrated to form the RF energy harvesting system. The maximum measured efficiency obtained at 2.4 GHz is about 63.7%.
Author(s): N. A. Eltresy, D. M. Elsheakh, E. A. Abdallah, H. M. Elhennawy
File Type: Journal Paper
Issue:Volume: 33      Number: 12      Year: 2018
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Title: Power Containment of Hybrid Electromagnetic Modes of Cylindrical Dielectric Waveguide
File Type: Conference Paper
Issue:Volume: Numerical Techniques for Electromagnetic Applications      Number:      Year: 2011
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Title: Polarization Isolation Characteristics Between Two Center-Feed Single-Layer Waveguide Arrays Arranged Side-by-Side
Abstract: Abstract - The near field coupling between two large alternating-phase fed single-layer waveguide arrays arranged side-by-side is analyzed by the Finite Element Method (FEM) (HFSS). First, the overall reflection as well as the radiation pattern from the array (320 slots and 18.4 λ x 14.9 λ) is analyzed, and excellent agreement with measurements is observed. Next, the isolation between two arrays is computed, and remarkable polarization isolations of more than 80 dB are predicted. The isolation is verified by measurements. The influence of the relative arrangement of the arrays upon the isolation is discussed.
Author(s): Yasuhiro Tsunemitsu, Jiro Hirokawa, Makoto Ando, Yohei Miura, Yasuhiro Kazama, Naohisa Goto, Yasuhiro Tsunemitsu, Jiro Hirokawa, Makoto Ando, Yohei Miura, Yasuhiro Kazama, Naohisa Goto
File Type: Journal Paper
Issue:Volume: 21      Number: 3      Year: 2006
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Title: Planar Metamaterial for Matched Waveguide Termination
Abstract: We present the design, fabrication, and characterization of a novel matched waveguide termination based on planar artificial metamaterial. This matched termination is realized by recent developed planar metamaterial absorber, which can be designed to near-completely absorb the propagating electromagnetic energy at the edge of a shorted rectangular waveguide. Theoretical discussions, numerical simulations and microwave experiments are employed to illustrate the matched characteristics of the proposed waveguide termination. As an example, a matched waveguide termination with standing wave ratio of 1.23 is experimentally demonstrated at microwave frequency. Our result yields a promising approach to design of novel waveguide terminations by techniques of metamaterials.
Author(s): J. Li, F. Wang, G. Wen, Y. Huang, W. Zhu
File Type: Journal Paper
Issue:Volume: 28      Number: 12      Year: 2013
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Title: Physics of Wave Propagation in Miniaturized Metamaterial-based Waveguides: Analytical, Numerical and Experimental Investigation
File Type: Conference Paper
Issue:Volume: Metamaterial Structures with Application to Guided-Wave Electromagnetics and Antennas      Number:      Year: 2007
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Title: Perturbation Approach to Shape Reconstruction in a Rectangular Waveguide using Experimental Data
File Type: Conference Paper
Issue:Volume: S21 Optimization and Inverse Problems in Low-Frequency Electromagnetic Fields      Number:      Year: 2018
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Title: Performance Optimization of Reconfigurable Reflectarray Antennas
File Type: Conference Paper
Issue:Volume: Latest Developments of Reflect/Transmit Array Antennas      Number:      Year: 2012
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Title: PERFORMANCE OF THE GENERALIZED MULTIPOLE TECHNIQUE (GMT/MMP) IN ANTENNA DESIGN AND OPTIMIZATION
Abstract: During the last decade, the generalized multipole technique (GMT) has been extensively studied, improved and applied to many electromagnetics problems such as bioelectromagnetics, optics, waveguides and electromagnetic compatibility (EMC), but little has been reported towards utilizing this method for antenna design and optimization. On the other hand, the few published examples of simple dipoles and helices in the close vicinity of lossy scatterers have suggested the potential significance of GMT for antenna design purposes. In this paper, the applicability of the GMT based 3D multiple multipole (3D MMP) code for simulation of wire antenna has been investigated. To evaluate the advantages and limitations of 3D MMP, several basic types of wire antenna configurations were simulated. These were linear and linear array, helical, and physically constrained low profile antennas. To validate the method's performance, we calculated radiation patterns, impedance, return loss, reflection coefficient, VSWR, and compared them to available results from experiments and/or results published by others using different techniques. This investigation showed several conceptual advantages of this technique for antenna simulations. Furthermore, the thin-wire expansion in combination with multipoles and roof top functions provides a great degree of flexibility in modeling. The most recently implemented expansion, "line multipoles," extends the code's efficiency to non-thin-wire configurations (e.g., helix with small ratio of pitch to wire diameter). Critical issues of modeling are the feedpoint and wire tip area, matching point locations and segment length-to- diameter ratio. Symmetries are used where possible to minimize computation time without loss of generality as any antenna element may easily be assembled in non- symmetrical configurations with the block-iterative solver. In order to achieve better confidence on more complex configurations, extensive studies were performed to increase efficiency and stability of modeling and will be discussed. In addition, the numerical validation techniques were extended to satisfy the special requirements of antenna simulations. These studies demonstrate the potential of GMT/MMP for use in analysis, synthesis and optimization of antennas. [Vol. 9, No. 3 (1994), Special Issue on Generalized Multipole Technique (GMT), pp 79-89]
Author(s): Roger Yew-Siow Tay, Niels Kuster, Roger Yew-Siow Tay, Niels Kuster
File Type: Journal Paper
Issue:Volume: 9      Number: 3      Year: 1994
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Title: Particle Swarm Optimization Applied to EM Problems
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D Software      Number:      Year: 2006
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Title: Parametric Model Generation Algorithm for Planar Microwave Structures based on Full–Wave analysis and Design of Experiment
File Type: Conference Paper
Issue:Volume: Time Domain Numerical Modeling Beyond FDTD      Number:      Year: 2003
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Title: Parametric Design of Open Ended Waveguide Array Feeder with Reflector Antenna for Switchable Cosecant-Squared Pattern
Abstract: This paper presents parametric analysis of two-dimensional (2D) open-ended waveguide array feeder and introduces a modified parabolic reflector antenna structure to obtain electronically switchable radiation patterns. The main motivation of the study is to achieve desired radiation characteristics for naval, air and coastal surveillance radars such as, pencil beam, suppressed side lobes and cosecant-squared pattern shapes. The Analytical Regularization Method (ARM) is used as a fast and accurate predesign tool to compute near and far field radiation characteristics of the feeder and reflector antennas. The numerical procedure is initially verified by the analytical methods and the calculated results are presented for the proposed novel designs.
Author(s): O. M. Yucedag, A. S. Turk
File Type: Journal Paper
Issue:Volume: 27      Number: 8      Year: 2012
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Title: PARALLEL IMPLEMENTATION OF GALERKIN TECHNIQUE IN LARGE SCALE ELECTROMAGNETIC PROBLEMS
Abstract: An intergal equation formulation in conjunction with a palallelised Galerkin technique is employed to solve large-scale electromagnetic (EM) problems. The proposed technique is applicable to EM structures consisting of similar conducting or dielectric parts, defined as "elements". Coupled intergal equations are derived in the frequency domain, written in terms of the conductivity currents or the electric fields deployed on the conducting or dielectric "elements" surfaces, respectively. The system of intergal equations is numerically solved via the parallel computed Galerkin technique, with convienient entire domain basis functions. Even for ellectrically large structures, the use of entire domain basis functions leads to relatively small order linear systems and the main computational cost refers to the matrix fill rather than the matrix solution. The parallalisation introduced to the computation of the matrix elements overcomes the limitation of using Method of Moments at lower and resonant frequencies. The inherent parallelisim of the introduced technique allows for the results to be obtained with minimal addition to sequental code programming effort. Two indicative electromagnetic compatibility applications are presented, concerning the coulping of incident waves with multiple conducting rectangular plates and the coupling phenomena occuring in a multi-element waveguide array looking into a layered lossy cylinder. Numerical results are presented, while the applicability/suitability of diverse High Performance Computing platforms is judged, based on both performance obtained and ease of code portation.
Author(s): D.I. Kaklamani, K.S. Nikita, A. Marsh, D.I. Kaklamani, K.S. Nikita, A. Marsh
File Type: Journal Paper
Issue:Volume: 14      Number: 3      Year: 1999
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Title: Padé Boundary Conditions for Finite Element Time Domain Beam Propagation Method
File Type: Conference Paper
Issue:Volume: S52 Novel Photonic Material and Devices II      Number:      Year: 2017
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Title: Overview of the Latest Additions to FEKO Suite 5.4 Enabling Faster Solutions to a Larger Variety of Electromagnetic Problems
File Type: Conference Paper
Issue:Volume: FEKO Modeling and Analysis I      Number:      Year: 2009
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Title: Optimum Design of SIW Longitudinal Slot Array Antennas with Specified Radiation Patterns
Abstract: In this paper, an optimum design is presented for substrate integrated waveguide (SIW) longitudinal slot array antennas based on the method of least squares (MLS). Elliott’s design procedure for dielectric filled waveguides is considered, taking into account the internal and external mutual couplings. The MLS error function is a multi-term function based on design goals, including specified radiation patterns and matching of the input impedance. We use the hybrid method of genetic algorithm-conjugate gradient for the error function minimization. This approach is very effective because of combining the “pattern synthesis” with “impedance matching” and “calculation of array parameters”. This procedure increases the speed of design as well as synthesizing patterns with specified characteristics. The MLS design results and those obtained by HFSS and CST simulation software are in good agreement and verify the accuracy of the proposed method.
Author(s): S. E. Hosseininejad, N. Komjani, H. Oraizim, M. T. Noghani
File Type: Journal Paper
Issue:Volume: 27      Number: 4      Year: 2012
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Title: Optimized Design of Substrate Integrated Waveguide Cavity based Oscillators
File Type: Conference Paper
Issue:Volume: Efficient Microwave Subsystem Design and Optimization      Number:      Year: 2010
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Title: Optimization of Aperiodic Waveguide Mode Converters
File Type: Conference Paper
Issue:Volume: CEM for Applied Analysis and Synthesis      Number:      Year: 2005
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Title: Optimal Design of Photonic Devices Using Time-Domain Beam Propagation Method
File Type: Conference Paper
Issue:Volume: S18 Time-Domain Techniques for Designing Electromagnetic and Optical Devices - I      Number:      Year: 2021
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Title: Optimal Design of Dielectric Layer PBG Filter Structure in Waveguide by Response Surface Methodology
File Type: Conference Paper
Issue:Volume: Efficient Optimization Techniques for High Frequency Structures      Number:      Year: 2013
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Title: Optimal Design of an Ultra-Wideband Antenna with the Irregular Shape on Radiator using Particle Swarm Optimization
Abstract: An ultra-wideband antenna with an irregular shape radiator for ultra-wideband applications has been designed by particle swarm optimization along with the simulator, HFSS. The proposed antenna design process is automated. Also, the better results can be obtained efficiently. The proposed antenna is fed by a coplanar waveguide line. The optimized antenna has a compact substrate size of 34.0 mm by 33.35 mm. Results show that the optimized irregular shape of the proposed antenna outperforms the antennas with uniform rectangular shapes in impedance matching. The optimized antenna can cover the spectrum of ultra-wideband (3.1 GHz - 10.6 GHz). The current distributions are investigated for describing the antenna characteristics. Moreover, the proposed UWB antenna has good characteristics of radiation, transmission, and impedance bandwidth.
Author(s): W. C. Weng
File Type: Journal Paper
Issue:Volume: 27      Number: 5      Year: 2012
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Title: Optimal Design for an Ultra-wideband Antenna Using Particle Swarm Optimization
File Type: Conference Paper
Issue:Volume: Optimization Methods for EM Applications      Number:      Year: 2012
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Title: Optical Crosstalk Improvement in Ring Resonator Based Add/Drop Multiplexers Using Controllable Reflectivity
Abstract: In this paper, the topic of optical signal integrity is approached by studying crosstalk suppression in ring resonator based optical Add/Drop Multiplexers (OADM). The resonance splitting induced by surface corrugation is exploited to enhance signal integrity by increasing the crosstalk suppression bandwidth compared to that of a smooth-walled resonator. Sidewall roughness in silicon-on-insulator waveguides is studied using Coupled Mode Theory (time and space domain CMT). An analytical model of a corrugated ring resonator is presented, which is then exploited to estimate the spectral response of the different ports. Verification against results generated from full-wave electromagnetic numerical modeling of a randomized corrugated ring is performed. The analysis then examines the performance of an OADM with controllable reflectivity resulting from a predefined corrugation of sidewall. Gratings have been successfully used in optical filters; this paper proposes the use of a grating in an OADM, giving more controlled roughness. A grating-assisted design of a single ring OADM with 28 GHz crosstalk suppression bandwidth is presented. This bandwidth supports the dropping of 10 Gbps signals with mitigated crosstalk levels and improved signal integrity.
Author(s): R. D. Mansoor, A. P. Duffy
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: ON THE USE OF BIVARIATE SPLINE INTERPOLATION OF SLOT DATA IN THE DESIGN OF SLOTTED WAVEGUIDE ARRAYS
Abstract: Essential to the design process of slotted waveguide arrays is an accurate knowledge of the self-properties of the individual slots. These properties can be computed with sufficient accuracy using moment method codes, which are too computationally intensive to be incorporated into design codes for large arrays. This paper describes an interpolation scheme which provides both sufficiently accurate, and rapid, computation of slot data from a pre-determined database to be viable for use in a slotted waveguide array design code. [Vol. 9, No. 1 (1994), pp 6-9]
Author(s): Derek A. McNamara, Johan Joubert, Derek A. McNamara, Johan Joubert
File Type: Journal Paper
Issue:Volume: 9      Number: 1      Year: 1994
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Title: On the Power Containment of Transverse Electromagnetic Modes of Cylindrical Dielectric Waveguide
File Type: Conference Paper
Issue:Volume: Application of Electromagnetic Simulation for Designing and Analysis of Antennas and Radio Propagations Part II      Number:      Year: 2014
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Title: On The Capacity of the Waveguide Indoor MIMO Channel
File Type: Conference Paper
Issue:Volume: Poster Sessions 1      Number:      Year: 2007
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Title: Numerical Analysis of Parallel Plate Waveguide Loaded with Magnetic Photonic Crystals (MPC\'s)
File Type: Conference Paper
Issue:Volume: Modeling Methods for Metamaterials      Number:      Year: 2006
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Title: Novel High Performance Low Cost Phase Shifters Design Based on the Ferroelectric Materials Technology Using the WIPL-D Code
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling Using WIPL-D Code(I)      Number:      Year: 2004
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Title: Novel Compact Substrate Integrated Waveguide Balun Filter and Balanced Filter
File Type: Conference Paper
Issue:Volume: 3-MA-2 Novel Multi-functional Integrated Microwave Circuits and Components      Number:      Year: 2018
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Title: Nondestructive Clamped-Waveguide Low-loss Material Extraction Technique
File Type: Conference Paper
Issue:Volume: Nondestructive Evaluation and Materials Characterization      Number:      Year: 2010
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Title: New FEKO Modeling Capabilities: Waveguide Ports with Dielectrics, Fast MLFMM based Near-Field Calculations, Integrated Network Modeling, and Dielectric GO
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling using FEKO – I      Number:      Year: 2008
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Title: Neural Network Technique Simultaneously Optimizing Antenna Return Loss and Radiation Pattern
File Type: Conference Paper
Issue:Volume: Electromagnetic Modeling with QuickWave/Concerto      Number:      Year: 2008
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Title: Neural Network Inverse Modeling Methods for Fast and Accurate Solution of Electromagnetic Devices
File Type: Conference Paper
Issue:Volume: Microwave Modeling and CAD      Number:      Year: 2009
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Title: Narrow Band, Sharp Roll-Off Rejection Frequency Selective Surface Based on Substrate Integrated Waveguide
Abstract: In this paper, a novel frequency selective surface which has a narrower passband and sharper rolloff rejection than the other single layer designs, is presented. Also, it has better independency from angle and polarization of incident plane wave. In this design a ring loop is placed on a cylindrical cavity of substrate integrated waveguide (SIW). Because of the most compatibility between loop and the electric fields of cylindrical cavity, minimum insertion loss and narrow passband are achieved.
Author(s): M. S. Samani, R. S. Shirazi, G. Moradi
File Type: Journal Paper
Issue:Volume: 30      Number: 7      Year: 2015
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Title: Multipactor in Dual-Mode Elliptical Waveguide
File Type: Conference Paper
Issue:Volume: S23 RF/Microwave Electromagnetics - Computational Modeling and Experiments      Number:      Year: 2015
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Title: Multilayer Half-Mode Substrate Integrated Waveguide Wideband Coupler with High Selectivity
Abstract: A novel 3dB wideband coupler with enhanced selectivity has been proposed and developed in multilayer HMSIW topology. Periodic ginkgo leaf slots (GLS) are etched on top layer of HMSIW to realize a pass-band combining with high-pass characteristics of HMSIW. The novel GLS cells have stop-band characteristics aiming to improve the frequency selectivity and extend the upper stop-band. Moreover, the roll-off at the upper side is very sharper. A continuous coupling slot is etched in the conductor layer at the broadwall of HMSIW. Coupling takes place through the long, offset slot, which features a flexible design providing a wide coupling dynamic range with wideband characteristics. Detailed design process is introduced to synthesize a wideband filtering HMSIW coupler with better stopband rejection. The novel coupler is showing a 34.9% coupling bandwidth at 8.87 GHz with good isolation, reflection and out-of-band rejection performances. Its stop band is from 13.8 to 17.6GHz with the rejection more than 40dB. Good agreement is obtained between the simulated and measured results of the proposed structure.
Author(s): Z. Zhang, Y. Fan, Y. Zhang
File Type: Journal Paper
Issue:Volume: 34      Number: 9      Year: 2019
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Title: Multi-Slot Antenna for Radar Systems
File Type: Conference Paper
Issue:Volume: Recent Antenna Applications      Number:      Year: 2003
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Title: Multi-Beams Waveguide Slot Antennas at X-Band for Wireless Communications Systems
Abstract: This paper focuses on the design of a multibeams antenna using waveguide slots technology at Xband. The multi-beams radiation is proposed to expand the coverage of the single antenna, thus more capacity is enabled. Waveguide slots antenna is a well-known antenna for high power and gain transmission capabilities. Therefore, it is preferred. In this work, four variations of waveguide slots antennas are studied. The slot distribution covers one to four broad and narrow walls of the waveguide. This technique enables multibeams patterns. The performance of the proposed antennas is simulated using CST microwave software. The simulated responses of the antennas show that a good matched with return loss greater than 10 dB at the desired frequency. The four proposed antennas achieved a good gain between 6.3 and 7.4 dB with directional beamwidth of 15 degree. The proposed antennas are suitable for implementing in radar applications.
Author(s): H. O. Hanoosh, M. K. A. Rahim, N. A. Murad, Y. M. Hussein
File Type: Journal Paper
Issue:Volume: 35      Number: 7      Year: 2020
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Title: Multi-Bandwidth CPW-Fed Open End Square Loop Monopole Antenna for Energy Harvesting
Abstract: Compact CPW-fed open end square loop monopole antenna is presented. The antenna can harvest ambient power at different radio frequencies of 1.8, 1.9, 2.4 and 5.2 GHz. The multi-band coplanar waveguide antenna (MCPW) is designed and fabricated on a very thin and lowprofile substrate. The proposed antenna is used to measure the ambient spectrum in two different places. One of them is indoor and the other is outdoor, in order to see the effect of the place on the proposed energy harvesting system. A multi-band rectifier circuit is designed and integrated with the proposed antenna. The maximum simulation efficiency is 60.98% at 1.9 GHz and -1 dBm input power. The maximum measured efficiency is 60.57% at 2.5 GHz and -1 dBm RF received power. Also, the proposed rectenna has 53.1% measured efficiency at 2.5 GHz and RF received power of -5 dBm.
Author(s): N. Eltresy, D. Elsheakh, E. Abdallah, H. Elhenawy
File Type: Journal Paper
Issue:Volume: 34      Number: 2      Year: 2019
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Title: Multi-Bandwidth CPW-Fed Open End Square Loop Monopole Antenna for Energy Harvesting
File Type: Conference Paper
Issue:Volume: S42 Wireless Implants for Biomedical Telemetry II      Number:      Year: 2018
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Title: Modified V-Groove Slot Waveguide for DNA Hybridization Detection
Abstract: Highly sensitive slot waveguides are introduced and studied for DNA hybridization detection. In this investigation, two different configurations based on V-groove silicon on insulator (SOI) waveguides are analyzed using full vectorial finite element method. The suggested designs rely on improving the light confinement through the slot region at an operating wavelength of 1.55 μm. The power confinement, power density (PD), and effective index of the supported modes are studied for the conventional rectangular slot waveguide and proposed designs. Further, the effect of adding a plasmonic layer to the reported slot waveguides is implemented. It has been shown that the plasmonic layer increases the light confinement in the slot region with high potential for DNA hybridization detection with good confinement through the slot region.
Author(s): E. ELDamarawy, A. M. Heikal, S. S. A. Obayya, M. F. O. Hameed
File Type: Journal Paper
Issue:Volume: 35      Number: 7      Year: 2020
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Title: MODIFIED REFLECTIVE SYMMETRIES FOR IMPROVING THE EFFICIENCY OF THE MMP CODES
Abstract: A more general concept for the treatment of symmetry in the 3D MMP codes allows considerable gains in usability. Up to now, symmetry decomposition of functions has been made with functions that are continuous across the symmetry plane. Now discontinuous symmetrizations are added. Possible continuity conditions in the symmetry plane can be enforced explicitly with matching points. Not only are problem sizes reduced, but the creation of good models in the MMP sense is considerably simplified in some common applications. The improved approach also illustrates some of the "classical" methods for calculating obstacles in waveguides. [Vol. 9, No. 3 (1994), Special Issue on Generalized Multipole Technique (GMT), pp 57-62]
Author(s): Fin O. Bomholt, Lars H. Bomholt, Fin O. Bomholt, Lars H. Bomholt
File Type: Journal Paper
Issue:Volume: 9      Number: 3      Year: 1994
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Title: Modified Broadband Half Mode Substrate Integrated Waveguide Cruciform Coupler
Abstract: In this paper, a cruciform coupler with Half Mode Substrate Integrated Waveguide (HMSIW) structure is presented. The prototype coupler consists of four half mode SIW structures, which are crossing each other at right angles. Also, two metallic posts are inserted in free section of junction in order to make coupling properties. Compact size and broadband operation are the features of this coupler. The size of coupler is reduced 24% in comparison to previous HMSIW cruciform couplers. A fractional bandwidth of about 35% is obtained. The coupler is designed and simulated by HFSS13. Here, the simulation results are compared with experimental results.
Author(s): Z. Mansouri, M. Kishihara, F. B. Zarrabi, F. Geran
File Type: Journal Paper
Issue:Volume: 29      Number: 11      Year: 2014
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Title: Modification of Vivaldi Antenna for 2-18 GHz UWB Application with Substrate Integration Waveguide Structure and Comb Slots
Abstract: In this paper have been developed two new Vivaldi antenna for UWB application at 2-18 GHz with SIW structure for linear phase center labeled as antenna I and antenna II. The proposed antennas have high gain and directional patterns with symmetric radiation pattern in phi=0 and phi=90 planes. The SIW structure is combined with Vivaldi antenna in order to improve the gain, pattern and phase center linearity. Similarly, for gain improvement at lower frequencies for SIW antenna and with less divergence in the gain, slots with comb models are proposed. The prototype antenna is printed and fabricated on Roger 4003 with ?r = 3.45 and thickness of 1.5 mm. The antenna’s total dimension is 120 mm × 160 mm. The simulation and experimental VSWR and the gain of antenna I and II is less than 2.5 and 6 dBi - 15 dBi, and 2.4 for 2.17-18 GHz and 8.2 dBi - 15.5 dBi in the entire frequency range of 2-18 GHz respectively. Likewise, the Vivaldi antenna phase center is investigated and finally the linear characteristic of the antenna phase center is presented with linear variation.
Author(s): F. B. Zarrabi, N. P. Gandji, R. Ahmadian, H. Kuhestani, Z. Mansouri
File Type: Journal Paper
Issue:Volume: 30      Number: 8      Year: 2015
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Title: Modelling Nonlinear Photonics Crystal Waveguides Using the Transmission Line Modelling Method
File Type: Conference Paper
Issue:Volume: Advances in Transmission-Line Matrix (TLM) Analysis Methods      Number:      Year: 2008
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Title: Modelling and Impact of 3D Print Inaccuracies on the Performance of Circular Waveguide Hybrid Coupler
File Type: Conference Paper
Issue:Volume: S22 Advances in Hybrid Material Additive Manufacturing of Antennas      Number:      Year: 2020
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Title: Modelling and Impact of 3D Print Inaccuracies on the Performance of Circular Waveguide Hybrid Coupler
Abstract: Circular waveguide hybrid coupler operating over a frequency range of ISM 57-64 GHz, additively printed and metal plated using electroless technique is introduced. Effects of orientation of print and thickness of intricate structures on the performance of circular waveguide hybrid coupler are presented. The structure is printed using commercially available stereolithographic (SLA) printer. Circulatory system operated by a peristaltic pump is used for selective silver deposition of the hybrid coupler.
Author(s): A. Bal, G. H. Huff
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: Modeling the RF Performance of a Small Array
Abstract: ABSTRACT - Large phased arrays can be reasonably accurately modelled in finite element programs, such as HFSS using an infinite array model of the embedded element. This approximation is not applicable to small arrays, where each element is in a different electromagnetic environment. Very small arrays of simple elements (of about 10 elements or less) can be modelled as a complete unit, but slightly larger or more complex arrays require additional techniques to be modelled accurately. The predicted performance of several versions of a small array has been compared using HFSS V9.5. The arrays contained either waveguide or printed dipole elements and, within the limits of available computing resources, solutions were generated for (1) complete array models, (2) half and quarter array models with symmetry planes, and (3) infinite array models.
Author(s): P. Foster, A. Wicks, P. Foster, A. Wicks
File Type: Journal Paper
Issue:Volume: 21      Number: 3      Year: 2006
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Title: Modeling of Photonic Waveguide for Biosensing
File Type: Conference Paper
Issue:Volume: Low Frequency Applications - 2      Number:      Year: 2006
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Title: Modeling Nonlinear Interactions Between RF And Optical Fields In Traveling Wave Modulators Using A Hybrid Approach
File Type: Conference Paper
Issue:Volume: New Techniques for Computational Electromagnetic Validation      Number:      Year: 2007
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Title: Modeling and Realization of Cavity-Backed Dual Band SIW Antenna
Abstract: Herein, substrate integrated waveguide technology is applied in order to design high performance dual-band microstrip patch antennas. Two microstrip patch antenna designs were studied and modeled in 3D electromagnetic simulators. The obtained optimal models were then realized and measured. The measurement performance of the proposed antenna designs were then measured for 2.4 and 5.6 GHz. The results suggest that the proposed model consisting of a modified microstrip cavity-backed antenna and a defected ground structure is a high performance and low cost solution for 2.4 and 5.6 GHz applications.
Author(s): M. A. Belen, P. Mahouti, A. Caliskan, A. Belen
File Type: Journal Paper
Issue:Volume: 32      Number: 11      Year: 2017
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Title: Modeling and Analysis of a Dual-Band Dual-Polarization Radiator Using FEKO
File Type: Conference Paper
Issue:Volume: FEKO Modeling and Analysis - 1      Number:      Year: 2006
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Title: Model Validation for a Waveguide Septum Polarizer
File Type: Conference Paper
Issue:Volume: FEKO Modeling and Analysis III      Number:      Year: 2009
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Title: Mode-Selective Corrugated Substrate Integrated Waveguide: A New SIW Transmission Line
File Type: Conference Paper
Issue:Volume: 6-ME-2 Broadband and Multiband RF Circuits II      Number:      Year: 2018
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Title: Mode Conversion Caused by Bending in Photonic Subwavelength Waveguides
Abstract: We study the propagation of light in a subwavelength planar waveguide with an angular bend. We observe the mode conversion of a guided wave with a symmetric beam profile impinging into the bending of a waveguide. The guided wave outgoing from the bend is a mixed set of symmetric and asymmetric modes. The amount of mode conversion through the bend is quantified by calculating the Fourier transform of the electric field profile. It is found that the conversion rate is a function of the bending angle.
Author(s): Y. J. Rodriguez-Viveros, D. Moctezuma-Enriquez, P. Castro-Garay, B. Manzanares-Martinez, C. I. Ham-Rodriguez, E. Urrutia-Banuelos, J. Manzanares-Martinez
File Type: Journal Paper
Issue:Volume: 30      Number: 12      Year: 2015
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Title: Mode Analysis of Waveguides in Layered Media
File Type: Conference Paper
Issue:Volume: S47 Integral Equation Solvers for Real-Life Applications I      Number:      Year: 2018
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Title: Modal Analysis of Wave Propagation in Straight and Curved Arched Tunnel Based on Equivalent Rectangular Tunnel Model
Abstract: In this paper, a model is presented to simulate wave propagation in straight and curved tunnels with arched cross section with imperfectly conducting walls. The model is based on treating the tunnels as a rectangular waveguide with imperfectly conducting walls, where the arched cross section of the tunnels is approximated with equivalent rectangular cross section. A scenario is considered to check the accuracy of this model. This scenario is verified by comparing experimental and numerical simulation results. Good agreement between the proposed model and the experimental results is obtained.
Author(s): H. M. El-Maghrabi, S. F. Mahmoud, M. El-Said
File Type: Journal Paper
Issue:Volume: 32      Number: 9      Year: 2017
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Title: Modal Analysis for a Waveguide of Nanorods Using the Field Computation for a Chain of Finite Length
Abstract: The propagation of light along an infinite 2D chain of silver nanorods is analyzed and the dispersion for this waveguide is computed using field computation for a finite chain of nanorods. In this work, generalized multipole technique is used for the analysis. This method calculates the imaginary and real parts of the propagation constant by exciting the chain in one end and observing propagation of modes along the chain far enough from the excitation. It is shown that a short chain of finite length is sufficient for the calculation of the phase constant while the attenuation constant requires a longer chain. Field distribution is depicted for even and odd modes and it is shown that in the simulated frequency range only two modes can be excited and can propagate along the waveguide.
Author(s): Y. Rahbarihagh, F. Kalhor, J. Rashed-Mohassel, M. Shahabadi
File Type: Journal Paper
Issue:Volume: 29      Number: 2      Year: 2014
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Title: Microwave/Millimeter Wave Metamaterial Development Using the Design of Experiments Technique
File Type: Conference Paper
Issue:Volume: Metamaterials      Number:      Year: 2005
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Title: Method of Moments Solution of Closed Chirowaveguides
File Type: Conference Paper
Issue:Volume: Guided Waves in Non-Standard Media      Number:      Year: 2008
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Title: Method of Moments (MoM) Modeling of Wave Propagation Inside a Wedge
Abstract: Method of Moments (MoM) is used to model guided wave propagation inside a nonpenetrable wedge waveguide and the results are validated against analytical mode-based exact solutions.
Author(s): G. Apaydin, L. Sevgi
File Type: Journal Paper
Issue:Volume: 29      Number: 8      Year: 2014
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Title: Method of Moments (MoM) Modeling for Resonating Structures: Propagation inside a Parallel Plate Waveguide
Abstract: Method of Moments (MoM) modeling inside resonating structures is discussed and a novel approach called Multi-MoM (Mi-MoM) is proposed. Propagation inside a two-dimensional (2D) non-penetrable parallel plate waveguide is taken into account. The Mi-MoM results are compared with the analytical reference solution. Practical ways of different source representations (untilted/tilted Gaussian beams) are also presented. Finally, surface irregularities inside the waveguide and their effects on the propagation are modeled with both Mi-MoM and the Split-Step Parabolic Equation (SSPE) method.
Author(s): G. Apaydin, L. Sevgi
File Type: Journal Paper
Issue:Volume: 27      Number: 10      Year: 2012
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Title: Measurement of Electromagnetic Parameters Based on Gap-Waveguide Structure
File Type: Conference Paper
Issue:Volume: 1-SP-4 Metasurfaces/Metamaterials Theory, Design and Applications I      Number:      Year: 2018
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Title: Mathieu functions of complex arguments and thier applications to the scattering by lossy elliptic cylinders
Abstract: The aim of this paper is to outline the theory for calculating the angular and radial Mathieu functions of complex arguments. These functions are required for the computation of analytic solutions of electromagnetic scattering by lossy dielectric elliptic cylinders and waveguides. The backscattered echo width of a lossy dielectric elliptic cylinder is compared with the special case of lossy circular and weakly lossy elliptic cylinders and excellent agreement is obtained in all cases. Tabulated and plotted numerical results of Mathieu functions are presented.
Author(s): Abdul-kadir Hamid, M.I. Hussein, H. A. Ragheb, M. Hamid, Abdul-kadir Hamid, M.I. Hussein, H. A. Ragheb, M. Hamid
File Type: Journal Paper
Issue:Volume: 17      Number: 3      Year: 2002
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Title: Manipulation of Electromagnetic Waves Based on New Unique Metamaterials: Theory & Applications
Abstract: Metamaterials are typically engineered by arranging a set of unit cells in a regular array throughout a region of space, thus, obtaining some desirable macroscopic electromagnetic behavior. The desired property is often one that is not normally found naturally (negative refractive index, near-zero index, etc.). Over the past few years, the flexibilities of the metamaterials in choosing the numerical value of the effective permittivity or permeability have led to kinds of novel theoretical and practical possibilities for different applications, ranging from microwave to optical regime. In this paper, the theoretical mechanism for constructing metamaterials is described, and the unique feature of electromagnetic waves can be manipulated is verified by their applicability to construct various devices or components Some typical application is given, including: (1) novel RF devices realized by optical transformation principle, such as energy concentrators and universal waveguide connectors; (2) metamaterial-based wave absorbers; (3) gain enhancement approach of aperture antennas by planar metamaterial lenses loaded; (4) ultra-thin lenses with dual-polarization filtering features; and (5) beam tunable antennas by metamaterial device. Undoubtely, the reported results suggest promising applications in the next-generation communication system.
Author(s): Q. Qu, K. Zhang, G. H. Yang
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Low-cost Two-layer Terahertz Transmitarray
File Type: Conference Paper
Issue:Volume: 2-2-B Millimeter Wave and Terahertz Antennas      Number:      Year: 2017
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Title: Low Sidelobe Leaky Wave Antenna Based on Gap Waveguide Technology
File Type: Conference Paper
Issue:Volume: 4-P4-D Millimeter-Wave GAP Waveguide Technology      Number:      Year: 2017
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Title: Low Side-Lobe Substrate Integrated Cavity Antenna Array Using Unequal Microstrip-Ridge Gap Waveguide Feeding Network at 94 GHz
File Type: Conference Paper
Issue:Volume: 4-P4-D Millimeter-Wave GAP Waveguide Technology      Number:      Year: 2017
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Title: Low Frequency Signal Generation during Fano Resonance Build-up Process
File Type: Conference Paper
Issue:Volume: S31 Electromagnetic/Thermal Modeling of Infrared/Optical Antennas      Number:      Year: 2021
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Title: Loss Analysis of Wideband RF MEMS Shunt Capacitive Switch in T and Pi-Match Configurations
Abstract: A wide bandwidth coplanar-waveguide (CPW) based RF MEMS capacitive shunt switch with pi-matched & T-matched having high impedance transmission lines is designed and simulated for broadband (18-40 GHz) application. The effects of variation in membrane width (50 & 70 mu m) of the switch and high-impedance transmission line length (300 – 600 mu m) between the switch structures on scattering parameters are studied. The variation in beam width has very little effect on return loss of the switch in up-state. The reduction in high-impedance transmission line length yields marginal improvement in return loss. In the down-state configuration, the return loss showed negligible change with the variation in beam width and high-impedance transmission line length. The isolation is found improved with the increase in beam width and high-impedance transmission line length in whole frequency range. Simulating the technical performance demonstrates the greater improvement in RF characteristics of the switch particularly in return loss in up-state position. In order to validate the obtained result, Artificial Neural Network (ANN) has been trained using ADS result. Comparison shows good agreement between ADS and ANN results.
Author(s): S. Suganthi, P. Thiruvalar Selvan, S. Raghavan
File Type: Journal Paper
Issue:Volume: 33      Number: 9      Year: 2018
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Title: Localized Plasmonic Enhanced Waveguide Modulator with High Speed Tunability Using Graphene
File Type: Conference Paper
Issue:Volume: 3-MA-4 EM Characteristic and Application of Graphene      Number:      Year: 2018
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Title: Liquid Crystal-Based Dielectric-Loaded Plasmonic Ring Resonator Filter
Abstract: A new tunable plasmonic filter based on liquid crystal dielectric loaded plasmonic waveguide is proposed and studied.
Author(s): S. M. Alavi, H. Armand
File Type: Journal Paper
Issue:Volume: 30      Number: 2      Year: 2015
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Title: LF Sky Wave Propagation Excited by a Horizontal Electric Dipole Towards Understanding of Its Radiation Mechanism
Abstract: In this paper, the electromagnetic pulses have been investigated based on the theory of wave-hop propagation. The approximate formulas are obtained for the electromagnetic field of a vertical magnetic dipole in the presence of an Earth-ionosphere waveguide. Based on the results obtained, the approximate formulas are derived readily for the ground wave and sky waves due to horizontal electric dipole excitation by using a reciprocity theorem. The corresponding computations and discussions are carried out specifically by analogy with those generated by a vertical electric dipole with the formulas in CCIR’s recommendation. It is shown that the sky wave pulses would interfere at certain distances and occur by different time-delays.
Author(s): H. Xu, T. Gu, J. Zheng, K. Li
File Type: Journal Paper
Issue:Volume: 33      Number: 6      Year: 2018
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Title: Late-time Instability in Finite Difference Modeling of Very-Low-Frequency Propagation in the Earth-Ionosphere Waveguide
File Type: Conference Paper
Issue:Volume: S39 Modeling Electromagnetic Waves in Plasma Environments      Number:      Year: 2018
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Title: Large Waveguide Slotted Array With Shaped Patterns
File Type: Conference Paper
Issue:Volume: S36 Antennas and Arrays      Number:      Year: 2019
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Title: Ka-band Planar H-plane Horn Array with Reduced Sidelobe Level
File Type: Conference Paper
Issue:Volume: 2-SE-1 Antennas for mmWave/THz and 5G Communications II      Number:      Year: 2018
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Title: Ka-band Planar H-plane Horn Antenna Based on the Concept of Complementary Source
File Type: Conference Paper
Issue:Volume: 1-P1-A Student Paper Contest      Number:      Year: 2017
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Title: Investigations on Corrugation Issues in SIW based Antipodal Linear Tapered Slot Antenna for Wireless Networks at 60 GHz
Abstract: In recent days, substrate integrated waveguide (SIW) technology is attracting a lot of interest in the development of millimeter-wave (MmW) based circuits due to its inherent advantages. Tapered slot antenna (TSA) with antipodal geometry is used to surmount the impedance matching constraint and to enhance electrical performance including gain, side lobes levels, and main beam pattern. This paper focuses on the design of antipodal linear tapered slot antenna (ALTSA) using SIW technique at 60 GHz for wireless local area network (WLAN) and wireless personal area network (WPAN) applications. The size of the proposed antenna is very compact (43.29 mm × 9.93 mm × 0.381 mm) and the substrate used is RT/ Duroid 5880. Corrugations have been investigated on both the edges to improve antenna gain, front-to-back ratio, and radiation patterns. Numerical simulations are performed using 3D-EM tools, high frequency structure simulator (HFSS) and CST microwave studio (CST MWS). The obtained results reveal that when corrugation is introduced in the antenna there is a significant improvement of 3 dB in gain, respectively. This study has been reported earlier in other frequency bands but rarely any literature has been reported of such development at 60 GHz.
Author(s): P. Shrivastava, D. Chandra, N. Tiwari, T. Rama Rao
File Type: Journal Paper
Issue:Volume: 28      Number: 10      Year: 2013
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Title: Investigation of an Explicit, Residual-Based, a Posteriori Error Indicator for the Adaptive Finite Element Analysis of Waveguide Structures
Abstract: The performance of an explicit, residual-based, a posteriori error indicator for directing a single level p-refinement of the finite element method, electromagnetic analysis of multiport waveguide structures is evaluated experimentally by considering three different structures. The error indicator consists of a linear combination of element volume and element face residuals. It is found that the indicator is generally very effective in identifying elements that need to be refined. It is also found that the relative weighting of the volume and face residual contributions to the error indicator plays an important role in its performance.
Author(s): Matthys M. Botha, David B. Davidson, Matthys M. Botha, David B. Davidson
File Type: Journal Paper
Issue:Volume: 21      Number: 1      Year: 2006
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Title: Integrated Simulation and Analysis of Super Large Slotted Waveguide Array
Abstract: Aiming at the simulation problem of the super large slotted waveguide array antenna, the parallel higher-order method of moment is used and the coupling effect between each slot element is taken into account to perform the integrated and accurate simulation. In order to ensure that the algorithm is efficient and stable in the parallel process, the BDPLU strategy is introduced to reduce the communication pressure and eliminates the redundant communication of the equation solving when pivoting, which speeds up the process of matrix equation solving. According to different types of waveguide port forms, the computation of rectangular wave port and coaxial wave port is studied, and a new parallel matrix filling technique of wave port is used to accelerate the matrix filling process. Numerical examples calculated at "Tianhe-2" supercomputer show that the algorithm can efficiently and accurately handle the simulation analysis of most types of complex slotted waveguide array.
Author(s): C. Zhai, Y. Liu, S. Jiang, Z. Lin, X. Zhao
File Type: Journal Paper
Issue:Volume: 35      Number: 7      Year: 2020
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Title: Integrated Disc-loaded Monopole Array Antenna and the Small PIFA Antennas
File Type: Conference Paper
Issue:Volume: Analysis and Design of Antennas for Wireless Communications      Number:      Year: 2007
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Title: Integral equation formulation for the impedance representation of aperture-coupled devices with finite wall conductivity
File Type: Conference Paper
Issue:Volume: Special Session: Recent Electromagnetics & Antennas Activities in the European Network "ACE"      Number:      Year: 2005
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Title: Indoor Wave Propagation Prediction for Corridors Segments with Partially Reflecting Walls by Using 3D Waveguide Modal Analysis
Abstract: In this paper, a model is presented to simulate wave propagation in indoor corridors with partially reflecting walls. The model is based on combination of modal analysis, dyadic Green’s function, mode matching method and generalized scattering matrix. A new approach to simulate the effect of partial reflectivity of the walls of the waveguide model is proposed. This approach is based on approximating the fields inside the space of the actual waveguide section by equivalent waveguide sections of larger dimensions with PEC (Perfect Electric Conductor) walls. A simple scenario is considered in order to check the accuracy of this model. This scenario is verified by comparing experimental and numerical simulation results. The obtained results show that the proposed model is suitable for predicting accurate electric field strength due to an electromagnetic source in an indoor environment with partially reflecting boundaries.
Author(s): H. M. El-Maghrabi, A. M. Attiya, E. A. Hashish
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: IMPROVED MODELING OF SHARP ZONES IN RESONANT PROBLEMS WITH THE TLM METHOD
Abstract: Several new modified nodes based on the symmetrical condensed node with stubs are proposed to solve the difficulty of the TLM method in modeling problems highly dependent on frequency. These nodes avoid the problem of indirect modeling at critical points, such as bends and corners, thus providing more accurate results and flexibility in the modeling of conducting parts. The new nodes are applied to specific problems of rectangular waveguides loaded with rectangular irises of finite width to verify their capability to predict resonant phenomena.
Author(s): J. A. Morente, J.A. Porti, H. Magan, O. Torres, J. A. Morente, J.A. Porti, H. Magan, O. Torres
File Type: Journal Paper
Issue:Volume: 14      Number: 2      Year: 1999
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Title: Improved Heating Uniformity of a 3-kWatt 2.45GHz Microwave Dryer Using Multiple Multi-Slotted Waveguides
File Type: Conference Paper
Issue:Volume: S26 Advances on Time Domain Modeling and Design II      Number:      Year: 2019
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Title: Hyperthermia treatment modeling: is prescriptive, quantitative SAR dosimetry to be preferred over thermal dosimetry?
File Type: Conference Paper
Issue:Volume: Computational RF and Thermal Dosimetry      Number:      Year: 2007
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Title: Hyperthermia Study in Cancer Treatment
File Type: Conference Paper
Issue:Volume: S52 Biomedical Applications      Number:      Year: 2018
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Title: Hybrid Plasmonic Waveguiding Model in a V-shaped Silicon Groove
Abstract: A modified V-shaped silicon groove waveguide, embeded with metal nanowire,which is coated with a low refractive index layer was proposed. Finite element method (FEM) is used to numerically simulate the characteristics of the hybrid plasmonic mode at the wavelength of 1550nm. The simulation results show that the hybrid plasmonic mode can be confined to the dielectric layer on the surface of the metal nanowire. Meanwhile, factors on the modal properties are analyzed. Low loss and strong mode confinement can be realized by adjusting the size of the dielectric and metal nanowires as well as the angle of the V-shaped groove. The overall performance of the proposed model is superior to that of traditional hybrid plasmonic waveguides.
Author(s): X.-J. Kuang, Z.-X. Huang, X.-Y. Cao, M. Kong, J. Shen, X.-L. Wu
File Type: Journal Paper
Issue:Volume: 34      Number: 6      Year: 2019
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Title: Hybrid of Moment Method and Mode Matching Technique for Full-Wave Analysis of SIW Circuits
Abstract: In this paper, a full wave analysis of substrate integrated waveguide (SIW) structures is presented based on the moment method in combination with the mode matching technique. Initially, input and output post pairs are terminated with two waveguide sections. Then waveguide width, as an unknown variable, is adjusted to obtain minimum reflection from the SIW. Field distribution in the structure and current density on posts as well as dispersion characteristic of the SIW are investigated. Also, by taking the advantage of the moment method, analysis of the structures with longitudinal discontinuity along the wave propagation direction is offered. Furthermore, versatile instances are analyzed and compared with experimental values, results from high frequency structure simulator (HFSS), and numerical methods in recent literature. Good agreement between the results verifies the accuracy of the hybrid method.
Author(s): R. Rezaiesarlak, M. Salehi, E. Mehrshahi
File Type: Journal Paper
Issue:Volume: 26      Number: 8      Year: 2011
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Title: Hybrid Nonlinear and Electromagnetic Design of an Active Oscillator SIW Cavity Backed Slot Antenna
File Type: Conference Paper
Issue:Volume: Student Paper Competition      Number:      Year: 2010
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Title: Hybrid Nonlinear and Electromagnetic Design of an Active Oscillator SIW Cavity Backed Slot Antenna
File Type: Conference Paper
Issue:Volume: Efficient Microwave Subsystem Design and Optimization      Number:      Year: 2010
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Title: Hybrid Electromagnetic and Non-Linear Modeling and Design of SIW Cavity-Backed Active Antennas
Abstract: This paper presents the modeling and implementation of planar passive and active cavity-backed antennas in substrate integrated waveguide (SIW) technology. The cavity-backed topology helps suppressing the undesired surfacewave modes and may provide better phase noise performance in the antenna oscillator. The use of SIW technology allows for a compact and costeffective implementation of the structure. The design of the active antenna involves both electromagnetic full-wave modeling for the radiating structure and nonlinear analysis of the active circuitry through harmonic balance and transient simulations. Single substrate prototypes of both passive and active antennas operating in X band are presented and measured, showing good agreement with simulated results.
Author(s): F. Giuppi, A. Georgiadis, M. Bozzi, S. Via, A. Collado, L. Perregrini
File Type: Journal Paper
Issue:Volume: 25      Number: 8      Year: 2010
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Title: HMSIW Cavity Filters Employing Various Complementary Split-Ring Resonators for Microwave Remote Sensing Applications
Abstract: In this work, bandpass filters employing half-mode substrate integrated waveguide (HMSIW) cavities and various modified complementary split-ring resonators (CSRRs) are presented. The two modified CSRRs, which are called as Type-I and Type-II CSRRs, can exhibit larger effective inductance and capacitance, and eventually to contribute to the size miniaturization of the resonators. Thereafter, as the two CSRRs are independently loaded into HMSIW cavities, the newlyformed HMSIW-CSRR cavity resonators can achieve more size reduction as compared with the HMSIW cavity with the conventional CSRR. To demonstrate the proposed concept, two HMSIW cavity bandpass filters independently loaded with the proposed Type-I and Type-II CSRRs are implemented. Experimental results shows that measurements of the proposed filters agree with their corresponding simulations well. Meanwhile, as compared with some similar works, the two proposed filters achieve size reduction of 76.8% and 78.6%, respectively, as well as good selectivity, illustrating their suitability for the system integration application in microwave remote sensing and radar systems.
Author(s): L. Wang, Z. He, Y. M. Huang, S. Ding, M. Bozzi
File Type: Journal Paper
Issue:Volume: 34      Number: 9      Year: 2019
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Title: Highly Efficient Technique for the Full-Wave Analysis of Circular Waveguide Filters Including Off-Centered Irises
Abstract: A rigorous method for the full-wave analysis and design of waveguide filters implemented in circular waveguide technology, and including offcentered circular irises, is presented. The implemented tool is based on an integral equation technique, which provides a full-wave representation of the elementary blocks of the analyzed components in terms of generalized impedance matrices. With the aim of improving the efficiency of the developed tool, the radial variation of the modal solutions of the circular waveguides has been expressed in terms of sinusoidal functions, thus avoiding the use of the more cumbersome Bessel’s functions employed in the classical formulation. Furthermore, line integrals have been used (instead of surface integrals) to compute the modal coupling coefficients of the planar waveguide junctions involved in the considered filters, thus drastically reducing the CPU effort related to the implemented tool. New designs concerning band-pass filters including off-centered circular irises are also provided. The obtained results show that the relative position of the considered circular irises can be considered as a new design parameter with a noteworthy influence on the electrical response of the investigated components. The accuracy of the proposed method has been successfully validated by comparing the obtained results with data extracted from both the technical literature and a commercial software based on the finite-element method.
Author(s): A. A. San-Blas, J. M. Roca
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Higher Order Mode Analysis in WIPL-D A Tutorial
File Type: Conference Paper
Issue:Volume: S37 Advances in Electromagnetic Modeling by WIPL-D I      Number:      Year: 2018
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Title: High-Order Nystrom Method for Computing Waveguide Modes
Abstract: We report a novel method for accurately computing the modes of an arbitrarily-shaped hollow waveguide. Our method uses a point-based (Nystrom) discretization of an integral operator over the waveguide aperture to compute the modes.
Author(s): J. J. Ottusch, S. M. Wandzura, J. J. Ottusch, S. M. Wandzura
File Type: Journal Paper
Issue:Volume: 17      Number: 1      Year: 2002
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Title: High-Efficiency and Wideband Bridge Linking Waveguide Waves and Spoof Surface Plasmon Polaritons
File Type: Conference Paper
Issue:Volume: 4-P4-H Properties, Modelling and Novel Concepts of Artificial Electromagnetic Structures      Number:      Year: 2017
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Title: High Performance Silicon Mach-Zehnder Interferometer Based Photonic Modulator
File Type: Conference Paper
Issue:Volume: S05 Novel Photonic Material and Devices I      Number:      Year: 2017
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Title: High Performance Low Cost Ferroelectric Phase Shifters Designed for Simple Biasing
File Type: Conference Paper
Issue:Volume: Special Session: Electromagnetic Modeling by WIPL-D      Number:      Year: 2005
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Title: High Gain Dielectric Loaded Exponentially Tapered Slot Antenna Based on Substrate Integrated Waveguide for V-Band Wireless Communications
Abstract: The conception of Substrate Integrated Waveguide (SIW) technology and Exponentially Tapered Slot (ETS) antenna are together used to design a high gain, and efficient planar dielectric loaded antenna for V-band wireless communications. To increase the gain of the antenna, a dielectric loaded portion is used in front of the antenna which works as a dielectric guiding structure and SIW is used to feed the proposed antenna. The dielectric loaded ETS antenna and compact SIW feed are fabricated on a single substrate, resulting in low cost and easy fabrication. The antenna with elliptical shaped dielectric loaded is fabricated using printed circuit board process. The measured gain of the single element antenna is 10.2 dB, while the radiation efficiency of 96.84% is obtained at 60 GHz. The Y-junction SIW power divider is used to form a 1×2 array structure. Measured gain of the 1×2 array antenna is 11.2 dB, while the measured radiation pattern and gain are almost constant within the wide bandwidth of the antenna.
Author(s): S. Ramesh, T. R. Rao
File Type: Journal Paper
Issue:Volume: 29      Number: 11      Year: 2014
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Title: Hexagonal Waveguides: New Class of Waveguides for mm-wave Circulaly Polarized Horns
File Type: Conference Paper
Issue:Volume: S19 Broadband Antennas and Applications      Number:      Year: 2018
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Title: H-Plane Horn Antenna with Slow-Wave Substrate Integrated Waveguide
File Type: Conference Paper
Issue:Volume: 1-SP-1 Antennas for mmWave/THz and 5G Communications I      Number:      Year: 2018
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Title: Use of the Simultaneous Diagonalization Technique in the Ax=lBx Eigenproblem Applied to the Computation of the Characteristic Modes
Abstract: Characteristic modes developed by Garbacz, Harrington and Mautz have long been used in the analysis of radiation and scattering from conducting bodies and apertures. For their computation, it is necessary to solve an eigensystem of the form Ax=lBx. If the matrices (A,B) are Hermitian and B is positive definite, the generalized eigenvalue problem can be accurately solved using the simultaneous diagonalization technique (SDT). Because of numerical approximations and rounding sometimes it may happen that the matrices properties deteriorate and the SDT procedure becomes inapplicable. In this work a new technique, developed recently by Higham and Cheng is proposed as a method to solve these deteriorate cases. It is applied to the computation of the characteristic modes for some scattering problems. Results are analyzed and discussed.
Author(s): Giovanni Angiulli, Francesca Venneri, Giovanni Angiulli, Francesca Venneri
File Type: Journal Paper
Issue:Volume: 17      Number: 3      Year: 2002
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Title: Uncertainty Analysis on Band-Stop Filter Using Data-Driven Arbitrary Polynomial Chaos
File Type: Conference Paper
Issue:Volume: S17 Uncertainty Quantification in CEM      Number:      Year: 2017
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Title: Uncertainty Analysis of the EMC Simulation Based on the Non-Intrusive Galerkin Method
Abstract: Recently, as a high-efficient uncertainty analysis method, the Stochastic Galerkin Method has been widely applied in EMC simulations. In this method, the original solver must be changed during uncertainty analysis. Thus, the realization of the Stochastic Galerkin Method may become impossible in some cases. In this paper, a novel method named Non-Intrusive Galerkin method is proposed in order to sove this problem. The performance of the proposed method can be clearly shown by calculating a published example.
Author(s): J. Bai, G. Zhang, L. Wang
File Type: Journal Paper
Issue:Volume: 34      Number: 8      Year: 2019
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Title: Uncertainty Analysis of Reflection Coefficient for a Coating with Random Flaws Using Adaptive Mesh and DGTD Method
Abstract: An imperfect coating shall cause uncertainties in the analysis of electromagnetic properties. To quantify the influence of irregularity, complexity, and uncertainty of the coatings for electronic devices, an adaptive mesh algorithm combined with the discontinuous Galerkin time domain (AM-DGTD) method is developed. The uncertain variations are incorporated into the proposed algorithm by an appropriate parameterization. The standard statistical analysis is performed to calculate the appropriate moments, i.e., mean and variance. The developed method is validated by modeling a dielectric coating with uncertain flaws in an adaptive mesh grid. The computed quantities of interest from numerical estimations are compared with the analytical values, these results agree with the physical explanation, and are in good agreement with the exact values, as demonstrated by numerical experiments.
Author(s): H. Li, I. Hussain, Y. Wang, Q. Cao
File Type: Journal Paper
Issue:Volume: 33      Number: 5      Year: 2018
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Title: Uncertainty Analysis in EMC Simulation Based on Improved Method of Moments
Abstract: Recently, many uncertainty analysis methods have been taken into consideration in electromagnetic compatibility (EMC) simulation. As a traditional method, the Method of Moments (MoM) owns many advantages compared with other methods, especially in calculating the high dimension problems. However, its main disadvantage is the poor accuracy. In this paper, the Richardson extrapolation has been used to improve the MoM in order to promote the accuracy. By using feature selective validation (FSV), the effectiveness of the improvement can be obviously shown compared with the standard results calculated by the Monte Carlo Method (MC).
Author(s): J. Bai, G. Zhang, L. Wang, T. Wang
File Type: Journal Paper
Issue:Volume: 31      Number: 1      Year: 2016
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Title: Ultra-wideband Miniaturized Electromagnetic Bandgap Structures Embedded in Printed Circuit Boards: Theory, Modeling and Experimental Validation
File Type: Conference Paper
Issue:Volume: Design and Analysis of Advanced Circuit Architectures      Number:      Year: 2005
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Title: Ultra-Wide Bandwidth Enhancement of Single-Layer Single-Feed Patch Antenna Using the Theory of Characteristic Modes
Abstract: The Theory of Characteristic Modes (TCM) is proposed as a systematic approach to antenna design to achieve the goal of finding the antenna structure with optimum broadband behavior. This theory provides a physical insight to the radiating nature of microstrip patch antennas and reduces the design optimization time. In this work, the resonant behavior of the highly radiating structure of the single U-slot rectangular patch on a single-layer ?r = 4.4 substrate is analyzed using TCM. Modal analysis of this single-layer structure with different single feed excitations concludes that VSWR ? 2 impedance bandwidth in the order of 96% can be achieved with a single T-probe feed. Experimental results, included here, show VSWR ? 2 impedance bandwidth in the order of 71%.
Author(s): M. M. Elsewe, D. Chatterjee
File Type: Express Journal Paper
Issue:Volume: 1      Number: 9      Year: 2016
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Title: Ultra-Wide Bandwidth Enhancement of Single-Layer Single-Feed Patch Antenna Using the Theory of Characteristic Modes
Abstract: The Theory of Characteristic Modes (TCM) is proposed as a systematic approach to antenna design to achieve the goal of finding the antenna structure with optimum broadband behavior. This theory provides a physical insight to the radiating nature of microstrip patch antennas and reduces the design optimization time. In this work, the resonant behavior of the highly radiating structure of the single U-slot rectangular patch on a single-layer epsilon r = 4.4 substrate is analyzed using TCM. Modal analysis of this single-layer structure with different single feed excitations concludes that VSWR less than or equal to 2 impedance bandwidth in the order of 96% can be achieved with a single T-probe feed. Experimental results, included here, show VSWR less than or equal to 2 impedance bandwidth in the order of 71%.
Author(s): M. M. Elsewe, D. Chatterjee
File Type: Express Journal Paper
Issue:Volume: 33      Number: 3      Year: 2018
Download Link:Click here to download PDF     File Size: 1705 KB

Title: Ultra-Wide Bandwidth Enhancement of Single-Layer Single-Feed Patch Antenna Using the Theory of Characteristic Modes
Abstract: The Theory of Characteristic Modes (TCM) is proposed as a systematic approach to antenna design to achieve the goal of finding the antenna structure with optimum broadband behavior. This theory provides a physical insight to the radiating nature of microstrip patch antennas and reduces the design optimization time. In this work, the resonant behavior of the highly radiating structure of the single U-slot rectangular patch on a single-layer epsilon r = 4.4 substrate is analyzed using TCM. Modal analysis of this single-layer structure with different single feed excitations concludes that VSWR less than or equal to 2 impedance bandwidth in the order of 96% can be achieved with a single T-probe feed. Experimental results, included here, show VSWR less than or equal to 2 impedance bandwidth in the order of 71%.
Author(s): M. M. Elsewe, D. Chatterjee
File Type: Journal Paper
Issue:Volume: 33      Number: 3      Year: 2018
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Title: Ultra-Compact Polarization Splitter Based on Silica Liquid Crystal Photonic Crystal Fiber Coupler
Abstract: An ultra-compact polarization splitter based on dual core nematic liquid crystal silica photonic crystal fiber (NLC-PCF) is proposed and analyzed. The refractive index difference between the NLC and silica material guaranties the index guiding through the reported splitter. The dual core NLC-PCF has strong polarization dependence due to the birefringence between the two polarized modes. The coupling characteristics of the proposed design are studied thoroughly using full vectorial fine difference method (FV-FDM) and the propagation analysis is performed by full vectorial finite difference beam propagation method (FVFD-BPM). The numerical results reveal that the reported splitter has short device length of 482 µm with low crosstalk better than -20 dB with wide bandwidths of 31.5 nm and 19 nm for the quasi TE and quasi TM modes, respectively. The compact coupling lengths as well as the low crosstalks over reasonable bandwidths are the main advantages of the reported dual core NLC-PCF.
Author(s): R. A. Hussein, M. F. O. Hameed, S. S. Obayya
File Type: Journal Paper
Issue:Volume: 30      Number: 6      Year: 2015
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Title: Ultra Wideband Antenna Analysis
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D software II      Number:      Year: 2009
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Title: Ultra Low profile, Unbalanced Fed Inverted F Antenna on Finite Conducting Plane
File Type: Conference Paper
Issue:Volume: EM Applications using WIPL-D      Number:      Year: 2012
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Title: Ultra Low Profile Inverted L Antenna on Parallel Wires
File Type: Conference Paper
Issue:Volume: EM Simulations Using WIPL-D Characterization      Number:      Year: 2010
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Title: UHF-HF RFID Integrated Transponder for Moving Vehicle Identification
Abstract: This paper presents a passive HF-UHF RFID integrated transponder for the identification of a moving vehicle. It consists of a single ISO 7810 ID-1 Card where both a UHF meander dipole antenna and an ISO 15693 commercial tag are arranged. The UHF antenna is designed by using a parametric analysis of the optimal shape of the meanders to obtain a proper conjugate matching between the antenna and the RFID microchip. A single-lane identification scenario is presented and simulated. The effects of the electromagnetic reflection and diffraction on the reading range as well as on the identification operations of a tagged vehicle are also investigated. Numerical simulations and experimental results on a prototype of the conduced transponder confirm the possibility of using this technology for the identification of a moving vehicle approaching a road-toll system with a relatively slow speed.
Author(s): A. Toccafondi, C. D. Giovampaola, P. Braconi, A. Cucini
File Type: Journal Paper
Issue:Volume: 25      Number: 6      Year: 2010
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Title: UHF Flared Notch Antenna Design for Linear Arrays
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D software II      Number:      Year: 2009
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Title: Two-dimensional Full-wave Scattering at One Million Wavelength Objects
File Type: Conference Paper
Issue:Volume: Challenges in Scattering, Radiation and Multi-domain Modeling      Number:      Year: 2009
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Title: Two Element UWB-MIMO Antenna with Modified Ground Stub Structure
File Type: Conference Paper
Issue:Volume: S12 Advanced Optimization of Electromagnetic Structures - I      Number:      Year: 2021
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Title: Two Element Phased Array Dipole Antenna on Finite EBG Ground Plane
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D Software      Number:      Year: 2007
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Title: Two Element Phased Array Dipole Antenna
Abstract: Two element array of dipole antennas with 90 degree phase difference feed is proposed for directional antenna applications. In the numerical analysis, the electromagnetic simulator WIPL-D based on the method of moment is used. At first, the distance between the two elements is fixed to be a quarter wavelengths at the design frequency of 2.45 GHz. The front-to-back ratio is calculated. Then, by adjusting the length of the two elements and the distance between the two elements, a front-to-back ratio of 15.3 dB is obtained. The relation between the front-to-back ratio of this antenna and the feed point currents is discussed. The measured input impedance with 90 degree hybrid
Author(s): Mitsuo Taguchi, Kotaro Era, Kazumasa Tanaka, Mitsuo Taguchi, Kotaro Era, Kazumasa Tanaka
File Type: Journal Paper
Issue:Volume: 22      Number: 1      Year: 2007
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Title: Two Element Phased Array Dipole Antenna
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D Software      Number:      Year: 2006
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Title: Two Dimensional Frequency-Angle Domain Adaptive Combined Interpolation Method for Electromagnetic Scattering Analysis of Precipitation Particles
Abstract: A combined 2-D interpolation method is proposed for the efficient electromagnetic scattering analysis of precipitation particles over a broad frequency and angular band. This method combines the cubic spline interpolation method and the Steor-Bulirsch model. The cubic spline interpolation method is applied to model the induced current over wide angular band. The Steor-Bulirsch model is applied to accelerate calculation over wide frequency band. In order to efficiently compute electromagnetic scattering, sparsematrix/ canonical grid method (SM/CG) is applied to accelerate the matrix vector multiplication in EFIE. Therefore, the calculation time of frequency and angular sweeps become shorter. Numerical results demonstrate that this combined method is efficient for wide-band scattering calculation of precipitation particles with high accuracy.
Author(s): J. Chen, J. Lin, Z. Liu, N. Li, P. Ping, X. Ping
File Type: Journal Paper
Issue:Volume: 32      Number: 3      Year: 2017
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Title: Tunable Metasurfaces for Filtering the Electromagnetic Waves Under Different Excitations
Abstract: In this study a tunable metasurface has been presented and evaluated for different excitation types. Tunability has been achieved by changing the substrate and geometrical properties. In order to obtain uniqueness, a parameter retrieval for the effective permittivity and permeability is performed using a version of the Nicholson-Ross-Weir (NRW) algorithm that is improved by implementing the Kramers-Kronig relationship. The results regarding the parametric and retrieval analysis are presented.
Author(s): S. Can, E. Karakaya, F. Bagci, A. E. Yilmaz, B. Akaoglu
File Type: Journal Paper
Issue:Volume: 31      Number: 9      Year: 2016
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Title: Tucker-FMM-FFT-Accelerated SIE Solver for Large-Scale Electromagnetic Analysis
File Type: Conference Paper
Issue:Volume: S20 The Application of Tensor and Matrix Decompositions to the Electromagnetic Analysis      Number:      Year: 2021
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Title: Truncation Error Analysis of a Pre-Asymptotic Higher-Order Finite Difference Scheme for Maxwell's Equations
Abstract: Pre-asymptotic higher-order methods are useful to the mitigation of numerical dispersion error in large-scale Finite-Difference Time-Domain (FDTD) simulations. Its truncation error is shown in this study to be 2 2 O O () () :: t s in general. In the limiting case where the CourantFriedrichs-Levy number approaches to zero, it becomes 2 4 O O () () :: t s .
Author(s): Y. Shao, S. Wang
File Type: Journal Paper
Issue:Volume: 30      Number: 2      Year: 2015
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Title: Transmission plane models for parallel-plane power distribution system and signal integrity analysis
File Type: Conference Paper
Issue:Volume: Applied CEM for EMC Applications      Number:      Year: 2006
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Title: Transient Response of a Thin Wire above a Real Ground using a Simplified Reflection Coefficient Approach
File Type: Conference Paper
Issue:Volume: Advanced EMC Modeling      Number:      Year: 2007
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Title: Transient Electro-Thermal Analysis of On-Chip Interconnects in the Presence of ESD Pulses Using DGTD Method
File Type: Conference Paper
Issue:Volume: 10-TE-1 Electromagnetic Environment Effects and Protection II      Number:      Year: 2018
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Title: Transient Electro-Thermal Analysis of a Common Source Amplifier Circuit with a Physics-based MOSFET Model
Abstract: An algorithm that combines a common source amplifier with the physics-based metal-oxidesemiconductor field effect transistor (MOSFET) model is proposed. By solving the coupled drift-diffusion model equations with spectral element time-domain (SETD) method, the distribution of electron quasi-Fermi potential, hole quasi-Fermi potential and the potential inside the MOSFET is obtained. The corresponding current densities and electric intensities distributed in the device can be used to couple the heat conduction equation. Furthermore, the Kirchhoff laws should be satisfied when the MOSFET device is inserted in the circuit. The Newton-Raphson method is used to solve the nonlinear circuit equations due to the existence of semiconductor devices. The transient electro-thermal characteristics of a common source amplifier circuit have been analyzed, and the numerical results demonstrate the validity of the proposed method.
Author(s): T. Pan, D. Ding, H. Li, X. Cheng
File Type: Journal Paper
Issue:Volume: 34      Number: 7      Year: 2019
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Title: Transient Current Distribution and Force Analysis of Three Phase Enclosure Type GIB Based on Field-Circuit Coupling FEM Method
Abstract: On the purpose of optimal design and online monitoring of three phase enclosure gas insulated bus (GIB), a 3-D circuit-field coupling FEM model has been developed. The current constriction effects in plug-in connectors are simulated by modeling contact bridges between contact surfaces and the influence of conductor gravity on contact resistance has been taken into account. The distributions of current which is constrained by external circuit are obtained from fieldcircuit coupling calculation and electromagnetic force, which is derived from electromagnetic field calculation, is used as load inputs in mechanical field analysis. The validity of calculation model is demonstrated by comparing with vibration experiments. The dynamic current distribution and electromagnetic force behaviors of three phase enclosure GIB under steady state and different short circuit conditions have been analyzed using the calculation model. Analysis results show that the uneven heating of contact fingers due to current distributions under steady state and contact fingers with smaller contact forces are seriously ablated by large short currents under short circuit conditions, and are the main contact degradation mechanism of plug-in connector. Conductor electromagnetic forces under single phase short circuit condition are larger than those of two phase and three phase short circuit conditions and the electromagnetic force peak moments under different fault conditions are not the same.
Author(s): X. Guan, B. Kang, N. Shu, Q. Yan, Z. Li
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Transient Analysis of Thin-Wire Antennas over Debye Media
Abstract: This paper presents a numerical procedure to calculate the time-domain response of thin-wire antennas over Debye media. The method is based in an expansion of the electricfield integral-equation in the time-domain (EFIETD), which accounts for the Debye media by using a reflection-coefficient approach. Resulting extended integral equation is subsequently solved by the method of moments. Numerical examples including Debye soils show not only the accuracy of the method but also a higher computational efficiency in comparison with other hybrid numerical techniques.
Author(s): M. F. Pantoja, A. R. Bretones, S. G. García, X. L. Travassos, R. G. Martín
File Type: Journal Paper
Issue:Volume: 27      Number: 3      Year: 2012
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Title: Transient Analysis of Dispersion Medium with Conducting Strips buried in Different Depth
File Type: Conference Paper
Issue:Volume: S46 Time-Domain Techniques for Designing Electromagnetic and Optical Devices - II      Number:      Year: 2021
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Title: Transient Analyses of Grounding Electrodes Considering Ionization and Dispersion Aspects of Soils Simultaneously: An Improved Multiconductor Transmission Line Model (Improved MTL)
Abstract: This paper proposes an approximate model in the frequency domain for transient analysis of grounding electrodes buried in ionized and dispersive soils. The proposed method, called multi-conductor transmission line model (MTL), can easily treat the frequency dependence of electrical parameters of soil. It can also incorporate soil ionization by gradually changing the respective electrode radius. Extensive simulation results are presented to confirm the accuracy of the MTL.
Author(s): S. S. Sajjadi, V. Aghajani, S. R. Ostadzadeh
File Type: Journal Paper
Issue:Volume: 34      Number: 5      Year: 2019
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Title: Transient Adjoint Sensitivities for Problems with Multiple Discontinuities exhibiting Space Dependent Properties
File Type: Conference Paper
Issue:Volume: Efficient Solutions to Inverse Electromagnetic Problems      Number:      Year: 2010
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Title: Towards Wideband Hyperthermia Treatment System
Abstract: This paper presents an overview of design and functionality of the essential modules proposed to build a wideband hyperthermia system. Description is provided of the waveform shaper, power amplifier and applicator array modules. Big data analysis is presented to accelerate energy localization depending on a time reversal technique. Simulation results are provided assuming a cylindrical head phantom characterized with wideband dispersive tissue properties, and the obtained field maps are shown in different planes to visualize energy localization process. Results reveal that wideband operation has the potential to enhance energy localization in deep tumor regions while eradicating hot spots, as compared to conventional narrowband systems.
Author(s): N. Nizam-Uddin, W. Alkadri, W. A. Malik, I. Elshafiey, A. F. Sheta
File Type: Journal Paper
Issue:Volume: 32      Number: 9      Year: 2017
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Title: Tolerance Analysis and Robust Design in Engineering Electromagnetics – An Interval Analysis Perspective Abstract
File Type: Tutorial Abstract
Issue:Volume: S56 Tolerance Analysis and Robust Design in Engineering EM      Number:      Year: 2017
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Title: TM scattering from nite rectangular grooves in a conducting plane using overlapping Tblock analysis
File Type: Conference Paper
Issue:Volume: Fast and Efficient CEM Methods      Number:      Year: 2005
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Title: Time-Domain Spectral Inversion Method for Characterization of Subsurface Layers in Ground-Penetrating-Radar (GPR) Applications
Abstract: Ground-Penetrating-Radar (GPR) data analysis has been widely utilized in subsurface and geophysics applications. One of the applications turning into great importance is multilayer subsurface hydraulic parameter identification and soil water content estimations. The classic GPR techniques have shown limitations in detecting deeper soil layers and unsatisfactory accuracy in estimating the electrical properties of the layers. Spectral inversion methods have been recently identified and developed to be an effective tool to tackle these problems. In this work, the spectral inversion method is extended in time-domain and a comprehensive formulation of the algorithm along with an improved well-defined cost function is presented. The Time-Domain Spectral Inversion (TDSI) method is then applied to environmentally-relevant multilayer soil geometries and the corresponding estimated electrical properties are drawn. The results show the TDSI method considerably ameliorates the performance of the inversion in terms of simplicity, accuracy, and applicability.
Author(s): Z. Motevalli, B. Zakeri
File Type: Journal Paper
Issue:Volume: 34      Number: 1      Year: 2019
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Title: Time-Domain Response of 3-D Structures Calculated Using WIPL-D
File Type: Conference Paper
Issue:Volume: Advances in Electromagnetic Modeling by WIPL-D Software      Number:      Year: 2007
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Title: Time Response Analysis of Cable over Anisotropic Half Space
File Type: Conference Paper
Issue:Volume: 9-P-2 Poster      Number:      Year: 2018
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Title: Time of Flight Extraction of Dispersive Lamb Wave by Ridge Analysis
File Type: Conference Paper
Issue:Volume: 5-P-1 Poster      Number:      Year: 2018
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Title: Time Domain Parabolic Equation Method for Scattering Analysis of Electrically Large Coated Objects by using Impedance Boundary Condition
Abstract: The time domain parabolic equation method (TDPE) is an efficient tool for analyzing electromagnetic (EM) scattering by electrically large objects. It reduces the cost of computational resources by dividing threedimensional solution space into multiple twodimensional transverse planes for calculating scattered fields one by one. For thin coated perfectly electrically conducting (PEC) objects, the efficiency of TDPE method will decrease if dielectric is considered to be meshed. As an approximate method, Leontovich impedance boundary condition (IBC) handles this problem by modeling a surface impedance on the outer surface of coating dielectric, instead of solving Maxwell's equations in the dielectric domain. Thus in this paper, TDPE method based on Leontovich IBC is proposed to analyze broadband scattering problems of large-scale coated PEC objects. Numerical results have validated the accuracy and efficiency of the proposed method.
Author(s): L. Guan, S. Tao
File Type: Journal Paper
Issue:Volume: 33      Number: 12      Year: 2018
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Title: Time Domain Analysis of Ultra-Wide Band Signals from Buried Objects Under Flat and Slightly Rough Surfaces
Abstract: The analysis of transient scattering for TMz (horizontally) polarization from a cylindrical perfectly conducting (PEC) object buried in a lossy medium is considered. Flat and slightly surface cases are considered for the dielectric halfspace. Our previous work using a decomposition method solution in frequency domain of TMz polarization is utilized to solve this scattering problem. Then, an inverse Fourier transform is used to get the time domain signals. Timing analysis is done by calculating the travelling time of reflected signals in the possible paths. Then, multiple reflections are identified using these travelling times. Finally, the results from the flat and slightly rough surface profiles are used to compare the effects of multipath propagation.
Author(s): S. MakalYucedag, A. Kizilay
File Type: Journal Paper
Issue:Volume: 28      Number: 8      Year: 2013
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Title: Time Domain Analysis of GaAS MESFET Transistors Excited by an Incident Electromagnetic Field
Abstract: A numerical method for the fully distributed modeling of Field Effect Transistor (FET) excited by an incident electromagnetic field using a Finite-Difference Time-Domain (FDTD) method is described. The transistor is modeled using the fully distributed model which consists of a configuration of the conventional equivalent circuit of the transistor and three coupled lines as each distributed element. The distributed source terms represent the coupling with an electromagnetic field in the equation which can be used in the Electromagnetic Interference (EMI) analysis. As a numerical example, the method is applied to a GaAs MESFET and the time domain results are presented.
Author(s): L. Mirzavand, A. Abdipour, R. Mirzavand
File Type: Journal Paper
Issue:Volume: 29      Number: 10      Year: 2014
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Title: Time Domain Analysis of a Microstrip Line Excited Compact Rectangular Dielectric Resonator Antenna
File Type: Conference Paper
Issue:Volume: FDTD and Applications      Number:      Year: 2004
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Title: Time and Frequency Evolution of Precursor Fields in Dispersive Media using FDTD and Joint Time-Frequency Analysis
File Type: Conference Paper
Issue:Volume: Electromagnetic Analysis of Wave Phenomena      Number:      Year: 2005
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Title: Three-Dimensional Electromechanical Coupled Analysis for Capacitive RF MEMS Switches
File Type: Conference Paper
Issue:Volume: Novel Modeling Techniques and RF MEMS      Number:      Year: 2006
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Title: Three-Dimension Finite Element Analysis of a Helical Motion Induction Motor
Abstract: The paper presents a three-dimensional finite element analysis applicable to all forms of sheet rotor, cylindrical, linear induction motor, as well as, helical motion induction motor. The analysis accounts for longitudinal and transverse end effects, skin depth and finite sheet thickness; furthermore, there is practically no restriction on the shape of magnetic circuit that can be considered. It yields detailed space profile of the state variables. The winding arrangement may include multi-polar system circumferentially and axially. The excitation produced by such winding is a helically traveling wave. The formulation results in a set of linear equations which are solved by point relaxation method. The solution algorithm employs power mismatch in the machine to indicate accuracy. The theory is supported by experimental results.
Author(s): J. H. Alwash, L. J. Qaseer
File Type: Journal Paper
Issue:Volume: 25      Number: 8      Year: 2010
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Title: THREE METHODS FOR EVALUATION OF FREQUENCY-DEPENDENT RESISTANCES AND INDUCTANCES OF MULTICONDUCTOR TRANSMISSION LINES
Abstract: Three methods for the analysis of frequency-dependent resistances and inductances of multiconductor transmission lines are outlined and compared. The first method comes from power-engineering applications, and it is based on a numerical solution of an integral equation for the distribution of the conductor volume currents. The second method is based on the perturbation technique. The third method comes from high-frequency applications, and it is based on the principle of equivalent surface electric and magnetic currents. [Vol. 9, No. 2 (1994), Special Issue on The Numerical Computation of Low Frequency Electromagnetic Fields, pp 43-56]
Author(s): Antonije R. Djordjevic, Tapan K. Sarkar, Antonije R. Djordjevic, Tapan K. Sarkar
File Type: Journal Paper
Issue:Volume: 9      Number: 2      Year: 1994
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Title: Three Dimensional Finite Element Analysis for the Study of Voltage Drop Behavior in Zinc Air Batteries under Load Conditions
File Type: Conference Paper
Issue:Volume: S20 Advanced Computational Techniques in Electromagnetics      Number:      Year: 2015
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Title: Thin Wire Representation of the Vertical Conductor in Surge Simulation
Abstract: Abstract— Simulation of very fast surge phenomena in a three-dimensional (3-D) structure requires a method based on Maxwell’s equations, such as the FDTD (finite difference time domain) method or the MoM (method of moments), because circuit-equation-based methods cannot handle the phenomena. This paper describes a method of thin wire representation of the vertical conductor system for the FDTD method which is suitable for the 3-D surge simulation. The thin wire representation is indispensable to simulate electromagnetic surges on wires or steel frames of which the radius is smaller than a discretized space step used in the FDTD simulation. A general surge analysis program named VSTL (Virtual Surge Test Lab.) based on the Maxwell equations formulated by the FDTD method is used to simulate the surge phenomena of a vertical conductor, including the effects of ground plane and without ground plane. By use of the Maxwell equations, VSTL is inherently able to take into account the three-dimensional geometrical features of a simulated structure unlike EMTP-type circuit-based transient programs. Comparisons between calculated results by the FDTD method, theoretical results and computed results by the NEC-2 (Numerical Electromagnetic Code) based on the MoM are presented to show the accuracy of the thin wire representation.
Author(s): Md. Osman Goni, Eiji Kaneko, Hideomi Takahashi, Md. Osman Goni, Eiji Kaneko, Hideomi Takahashi
File Type: Journal Paper
Issue:Volume: 19      Number: 1      Year: 2004
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Title: Thermal-Aware DC IR-Drop Co-Analysis of 3-D ICs using Non-Conformal Domain Decomposition Methods
File Type: Conference Paper
Issue:Volume: Multi-Physics Modeling and Simulations      Number:      Year: 2012
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Title: Thermal Simulation of a Conductive Fabric Sheet Subjected to a Lightning-like Current
File Type: Conference Paper
Issue:Volume: S14 Numerical Methods for Diverse Applications      Number:      Year: 2020
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Title: Thermal Simulation of a Conductive Fabric Sheet Subjected to a Lightning-like Current
Abstract: A sample of electroconductive fabric subjected to a lightning-like current impulse is analyzed in this contribution. A multiphysics simulation is used to calculate the temperature distribution produced by a lightning-like current flowing through the material sample. A decoupled, electromagnetic (EM) and thermal, simulation was conducted for the analysis and is explained in the paper. The scaling factor calculation to represent the energy presented during current impulse tests is also detailed. Numerical results present patterns that agree with experimental tests reported in the literature and represent an additional tool for the phenomena insight.
Author(s): J. J. Pantoja, C. Rivera, J. Cristancho, J. Rodriguez, F. Roman
File Type: Journal Paper
Issue:Volume: 35      Number: 11      Year: 2020
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Title: Thermal Effects of 5G Frequency EM Waves on Ocular Tissue
Abstract: This research article aims to investigate the thermal effects on human eye due to exposure of EM (electromagnetic) field at 5G frequencies. A secondary purpose of the article is to show that SPICE, one of the most commonly used tools in circuit analysis, can be used to solve complex EM and bioheat transfer problems. Both electric field and temperature distributions in human eye are simulated with transmission line modelling (TLM) method. Also, finite element method (FEM) calculations are carried out for comparison. Temperature distributions are calculated for 30 minutes of EM radiation exposure. As a subject of the simulation, a human is chosen that the power density of incoming field at the human eye is assumed as the maximum of the ICNIRP general public exposure limits. A good consistency between TLM and FEM based simulations is found. A new transmission line model based on Debye parametric model is generated for simulation of EM field distribution in the tissues. With this generated transmission line, the results for the frequencies of interest can be obtained via single simulation. Also, a new transmission line model is developed for the temperature distribution simulation in which the effects of noncompressible fluid flow such as non-unidirectional blood flow in tissues and flow in aqueous humor are taken into consideration.
Author(s): B. Aricioglu, A. Ferikoglu
File Type: Journal Paper
Issue:Volume: 36      Number: 4      Year: 2021
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Title: Thermal Analysis and Phase Transformation of Ti6Al4V Alloy Fabricated by Direct Metal Laser Sintering
File Type: Conference Paper
Issue:Volume: S36 Large Scale Computing - I      Number:      Year: 2021
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Title: The Tilted-Ellipse Representation of Standing-Wave Patterns.
File Type: Conference Paper
Issue:Volume: Advances in CEM      Number:      Year: 2004
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Title: The Theoretical Analysis on Electromagnetic Signal Transmission for Down-hole to Surface
File Type: Conference Paper
Issue:Volume: 2-P2-A Electromagnetic Theory      Number:      Year: 2017
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Title: The Synthesis of Frequency Selective Surfaces for Infrared Filters
File Type: Conference Paper
Issue:Volume: Nanoscale Frequency Selective Surfaces      Number:      Year: 2006
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Title: The Sinusoidal Ground Electrode: Theory and Case Study Results
Abstract: This paper presents the analytical analysis of the sinusoidal ground electrode commonly used in Portugal by the Portuguese Electric Company. This electrode is easy to install, particularly for two layer soils with rocky bottom layer, and costs much less than it does a strip conductor. Both the theoretical results as well as measurements in the field have shown that the empirical model used by the company leads to large errors. Here the authors propose a new procedure to calculate the grounding resistance for this type of electrode using the average resistance between the wire and strip electrodes, which the calculation is well-established. To avoid heavy computation, the authors also propose the use of simple formulas in order to easily compute the strip resistance. The theoretical results and field measurements are compared and show the validity of the procedure being proposed here.
Author(s): A. M. R. Martins, S. J. P. S. Mariano, M. R. A. Calado, J. A. M. Felippe de Souza
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: The Role of High Fidelity Geometry Import in RF Modeling
File Type: Conference Paper
Issue:Volume: FEKO Modeling and Analysis IV      Number:      Year: 2009
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Title: The Reduction of Force Component Produced by Short Sides by Analyzing the Corner of Coil in Planar Motor with Halbach Magnet Array
Abstract: The planar motor with moving-magnet is purely levitated by the stator coils. The forces produced by coils are calculated with the analytical model of magnet array and coil surface model for applying to the real time control. Take the coil and the Halbach magnet array which is at 45 degree with the long side of coil for analysis. The force component produced by short sides can be eliminated for conveniently controlling when the length of coil takes certain dimension. In practice, the force component produced by short sides is small but not zero. There are two reasons, one is the higher harmonics and the other is the corner segments of coil. The force integral expressions of coil corner segments are given by the Lorenz force law. Then the forces numerically calculated with harmonic model and coil full model are verified by comparing with the magnetic surface charge model and finite element model. In order to reduce the force component produced by short sides, the different corners of coil are analyzed. Comparing the forces of different corners of coil, the force component produced by short sides can be significantly reduced with slightly change of the other force components.
Author(s): G. Liu, S. Hou, W. Xiao
File Type: Journal Paper
Issue:Volume: 36      Number: 1      Year: 2021
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Title: The Partial Element Equivalent Circuit Technique for EMI, EMC, and SI Analysis
File Type: Newsletter Paper
Issue:Volume: 21      Number: 1      Year: 2006
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Title: The Parallel FETI-DPEM Eigensolver for Analysis of 3D Electromagnetic Cavities
File Type: Conference Paper
Issue:Volume: Parallelized Computing for Accelerated EM Applications      Number:      Year: 2009
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Title: The Optimal Design of Real Time Control Precision of Planar Motor
Abstract: In this paper, the Halbach permanent magnet array with 2 segments per pole is selected for analysis. The harmonics that the harmonic numbers for the lx and ly-direction in local coordinate system are equal to each other are set as a pair for transformation. Then the expressions of the magnetic flux density distribution of the Halbach array in global coordinate system are derived. The dimensions of the coil are parameterized. The force and torque exerted on the Halbach array by a coil are calculated by Lorentz force law. The first three harmonics are chosen for real time control by analyzing the ratio of each harmonic in the total harmonics. The harmonic model has good performance on torque by comparing with the models used before. As for the force, the errors can be significantly reduced by optimizing the parameterized dimensions of coil because of the cosine or sine form error figures. The optimized model has good precision on both force and torque. The same method can be applied on the Halbach permanent magnet array with different segments per pole.
Author(s): G. Liu, Y. Wang, X. Xu, W. Ming, X. Zhang
File Type: Journal Paper
Issue:Volume: 32      Number: 10      Year: 2017
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Title: The Novel Adaptive Method for Interference Suppression
File Type: Conference Paper
Issue:Volume: S55 Devices and Applications      Number:      Year: 2018
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Title: The Influence of Thermal Deformation on the AMB-rotor System of HTR-PM Helium Circulator
Abstract: Helium circulator is the core component of High Temperature Reactor-Pebblebed Modules (HTRPM), and its rotor is supported by active magnetic bearings (AMBs). The windings of the motor and AMBs will generate a great deal of heat due to Ohmic loss, which increases the temperature of the circulator. The high temperature will cause the thermal deformation of AMB-rotor system, leading to the clearance change between rotor and AMBs. The AMB stiffness and inductive transducer sensitivity will be affected by the changed clearance, which decrease the stability of the AMB-rotor system. In this paper, through theoretical analysis and finite element analysis (FEA), the influence of thermal deformation on the AMB stiffness and transducer measurement is studied. The simulation and experiment for the AMB-rotor system in the circulator is carried out to explore the performance of AMB controllers and the influences of thermal deformation on the unbalanced response of the AMB-rotor system is analyzed. The theoretical calculations in this paper has general applications in the controller improvement of AMBs under clearance change and provides a reference for mechanical structure design and controller design of AMBs.
Author(s): J. Yu, G. Du, H. Wang, Z. Sun, L. Zhao
File Type: Journal Paper
Issue:Volume: 34      Number: 7      Year: 2019
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Title: The Influence of Non-uniform Flow Field Characteristics of Hypersonic Vehicle on Electromagnetic Wave Propagation
File Type: Conference Paper
Issue:Volume: 1-SP-2 Electromagnetic Characteristics of Complex Media Simulated by Time Domain Method I      Number:      Year: 2018
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Title: The Human Body Modelled by Canonical Geometric Shapes for the Analysis of Scattered E-fields
Abstract: The objective of this paper is to propose a simplified model of a human body to be used in electromagnetic problems involving high frequency field scattering. Canonical geometric shapes, analytically described, represent the body. The accuracy of the model was tested comparing the fi