ACES Publication Search





There are 12 search results for:



Title: July 2006 Full Journal
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 3650 KB

Title: July 2006 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 410 KB

Title: The Spherical Harmonic Interface Procedure for MM and UTD Codes
Abstract: This paper describes the use of a spherical harmonic expansion as an efficient interface between a low frequency method of moments (MM) code and a high frequency uniform geometrical theory of diffraction (UTD) code. It is shown that the method can save significant CPU time in the UTD code provided that the number of MM current filaments per cubic wavelength is large.
Author(s): J. T. Rockway, E. H. Newman, R. J. Marhefka
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 278 KB

Title: Mutual Coupling between Monopoles on F-4 Aircraft at Transition Frequencies: A Comparison between MoM and MoM/UTD Hybrid Method at UHF Band
Abstract: In this paper, the analysis of mutual coupling between monopole antennas mounted on the aircraft at UHF band is presented. The Method of Moments (MoM) and hybridized MoM with Uniform Geometrical Theory of Diffraction (UTD) method (MoM/UTD) are used to calculate the coupling in 225 MHz-400 MHz frequency range. Numerical results with MoM and MoM/UTD are performed and the reliability of these methods is discussed based on the measurement results.
Author(s): Ali Dagdeviren, Osman Cerezci, Fatih Ustuner, Bahattin Turetken
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 275 KB

Title: A New Iterative Method to Compute the Higher Order Contributions to the Scattered Field by Complex Structures
Abstract: A method to compute the higher order contributions to the scattered field by complex structures is presented in this paper. The method is based on a new interpolation technique to represent the induced current with a very low amount of sample points and computational cost. The amplitude and phase of the current are represented separately. Both are defined by an interpolating function, which is built using Bézier surfaces. These functions provide the amplitude and the phase at any given point of the scattering surface in an easy way. The higher order contributions to the scattered field are obtained by using a new iterative method based on Physical Optics (PO) and the Stationary Phase Method (SPM) to compute the integral. The proposed method takes advantage of the saving in computation cost offered by the new representation of the currents reducing the order of the function which is necessary to minimize, in order to obtain the stationary phase points required to evaluate the PO integral. The results obtained show that the method is both efficient and accurate.
Author(s): F. Saez de Adana, O. Gutiérrez, L. Lozano, M.F. Cátedra
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 372 KB

Title: The Use of Multiquadric Radial Basis Functions in Open Region Problems
Abstract: With the advent of neural networks, there has been a significant amount of research utilizing radial basis functions. In this paper, radial basis functions in conjunction with a meshless algorithm are used to solve electromagnetics problems in both open and closed regions. The algorithm for the solution of partial differential equations using the radial basis functions and development of the absorbing boundary condition will be discussed in detail. Several example problems will be discussed.
Author(s): Richard K. Gordon, W. Elliott Hutchcraft
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 240 KB

Title: A Novel Dual-band Small Size Microstrip Antenna
Abstract: A new small size dual-band microstrip antenna structure is proposed. The antenna consists of two resonant elements designed separately and integrated in such a manner to improve the compactness of the dual band structure and maintain the performance of each element. The structure is analyzed using lumped element approach and design curves are produced. The proposed approach is validated through a design example using theoretical curves and simulations. Implementation of an antenna operating in the 900 MHz and 1800 MHz bands is presented and comparisons between simulated and experimental results are given.
Author(s): Abdel Fattah Sheta, Hoda Boghdady, Ashraf Mohra
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 290 KB

Title: An Efficient Broadband Analysis of an Antenna via 3D FEM and Pade Approximation in the Frequency Domain
Abstract: The paper presents a finite element model for the calculation of the impedance of an antenna over a wide frequency band. The antenna has been designed to analyze a rectenna (rectifying antenna) in the context of wireless microwave energy transfer. The modelling approach combines a 3D edge element method (FEM) with a Padé approximation procedure. It allows to obtain an explicit expression of the impedance over a large frequency band. The comparison of the proposed technique with a standard finite element method shows that the computational cost is significantly reduced.
Author(s): Brahim Essakhi, Lionel Pichon
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 268 KB

Title: EBG Design using FSS Elements in Rectangular Waveguide
Abstract: A novel waveguide based EBG structure is originated by periodically loading FSS strip elements in rectangular waveguide. Efficient and accurate Hybrid MoM-Immiittance Approach is used for the full-wave characterization, which is validated by experimental results. A parametric study of effect of various factors on the EBG width has been done. Various existing and novel FSS strips have been investigated to improve the roll-off characteristics in the passband. Double square loop FSS strip loaded waveguide gives improvement in the roll-off factors. Such novel waveguide based EBG structures may be used in the design of harmonic suppressed waveguide filters, band reject filters and suppression of harmonics for waveguide resonators or antennas.
Author(s): R. S. Kshetrimayum, L. Zhu
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 485 KB

Title: Electromagnetic Modeling and Design of Dual-Band Septum Polarizers
Abstract: A highly efficient, full-wave electromagnetic model and CAD of septum polarizers terminated with a square or circular output waveguide is presented. The model is based on the mode-matching and generalized S-matrix techniques. The capabilities of the CAD program are demonstrated by the design of dual-band polarizers where the separation between two bands is more than 50%. For a square output polarizer, results are compared and found to be in good agreement with data obtained with the WASP-NET program. A discussion on the inherent limitations of the achievable performance and critical parameters is presented. An influence of higher-order modes propagating in the polarizer output over the high-frequency operation band on the radiation and polarization patterns of a septum polarizer combined with a corrugated conical horn is specially investigated.
Author(s): Anatoliy A. Kirilenko, Dmitriy Yu. Kulik, Leonid A. Rud, Vladimir I. Tkachenko, Naftali Herscovici
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 432 KB

Title: The Influence of Data Density on the Consistency of Performance of the Feature Selective Validation (FSV) Technique
Abstract: The human visual system has an immense capacity for compensating for poor or incomplete data. Psycho-visual coding schemes make use of the brain’s ability to extrapolate and interpolate independently of conscious awareness to reduce data (bit) rates but maintain the same level of ‘information’ within a video signal. However, when attempting to produce a simple method for comparing data-sets, primarily for validation of computational electromagnetics, could give rise to a problem. Namely that someone undertaking the visual inspection of (e.g.) modeled data against experimental data will see the same picture whether sampled at N, 100N or 0.01N data points whereas the software undertaking the comparison would process three very different data sets. The Feature Selective Validation (FSV) method was developed to attempt to mimic the group response of a number of experts undertaking the visual comparison. Hence, the quality of performance of the FSV method should not be severely affected by the number of data points if this assertion is to hold, despite the obvious potential for variation. This paper investigates the FSV performance as a function of data density and shows that the accuracy of its performance remains largely unimpeded by variations in the precision of the data supplied.
Author(s): Alistair Duffy, Antonio Orlandi
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 294 KB

Title: To-Average or Not-to-Average in FDTD Modeling of Dielectric Interfaces
Abstract: Accurate Finite Difference Time Domain (FDTD) modeling of localized electromagnetic sources such as cellular telephones near the human body requires very precise modeling of the location of these devices. This paper discusses the effective location of near field sources when dielectric interface cells are made up of either averaged or unaveraged dielectric properties. It is shown that either method can accurately define the proximity between source and dielectric, but that the effective location differs by half an FDTD cell in the two methods.
Author(s): Cynthia Furse, Craig Waterman, Lance Griffiths
File Type: Journal Paper
Issue:Volume: 21      Number: 2      Year: 2006
Download Link:Click here to download PDF     File Size: 306 KB