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Title: ACES Journal November 2015 Cover
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: ACES Journal November 2015 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: ACES Journal November 2015 Full
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Method of Moments Analysis of Electromagnetic Transmission Through an Arbitrarily Shaped 3D Cavity in a Thick Conducting Plane
Abstract: The method of moments (MOM) with surface equivalence principle is used to numerically solve the problem of electromagnetic scattering from and transmission through an arbitrarily shaped 3D cavity in a thick conducting plane is considered. The conducting walls of the cavity inside the ground plane are of arbitrary shape. The apertures at both ends of the cavity are also of arbitrary shape. An equivalent surface magnetic current placed on the top aperture produces the scattered field in the region where the impressed sources are. The total field inside the cavity is produced by two surface equivalent magnetic currents on the apertures and an equivalent surface electric current residing on the walls of the cavity as well as on both apertures. The transmitted field on the opposite side of the impressed sources is computed by an equivalent surface magnetic current residing on the bottom aperture. Computed results are compared with results in the literature obtained by using other methods. Very good agreement is observed.
Author(s): A. B. Olcen, S. T. Imeci, M. Gokten, J. R. Mautz, E. Arvas
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: A VSIE Solution for EM Scattering Using the Multilevel Complex Source Beam Method
Abstract: Multilevel complex source beam (CSB) method is introduced to accelerate the volume-surface integral equation (VSIE) for the analysis of electromagnetic scattering from the composite structures comprising conductor and dielectric material. The field generated by each basis function or testing function is expressed by use of the equivalent point source defined over the complex sphere. The far interactions between basis functions and testing functions are replaced by the interactions between complex point sources, which can be calculated efficiently by taking advantage of the directionality of the complex point sources. The translation invariance property of Green’s function is exploited to further improve efficiency. In numerical examples, the number of CSBs and truncation angle are given for each level, and the computational efficiency of the proposed method is validated by comparison with the conventional VSIE method.
Author(s): Z. H. Fan, Y. L. Hu, D. Z. Ding, R. S. Chen
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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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
Download Link:Click here to download PDF     File Size: 595 KB

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: Size Reduced Array Antenna with Enhanced Directivity
Abstract: Small array antennas with directive coverage are an attractive solution for size limitation in wireless devices. In this paper, the design of a directive 10 GHz antenna with reduced size microstrip array and frequency selective superstrate (FSS) is presented. Inductive loading and reduced patch separation is used to incorporate 7-elements within a 100x30 mm2 array aperture. The superstrate (FSS) layer is optimized to properly excite the Fabry-Perot cavity and further increase the antenna directivity. Using HFSS software, the reflection response and the radiation pattern of the antenna array is optimized. The simulated responses agreed well with the measured results.
Author(s): S. S. I. Mitu, F. Sultan
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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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
Download Link:Click here to download PDF     File Size: 957 KB

Title: A Simple Electromagnetically Fed Circularly-Polarized Circular Microstrip Antenna
Abstract: Existing literature on circularly polarized antennas fed with a microstrip transmission line does not include a systematic methodology to control and tune the reflection coefficient (S11) and axial ratio (AR). To enable systematic tuning of those performance metrics, this study proposes a new, circularly polarized, circular microstrip patch antenna with truncated square slot. A combination of an edge-truncated square-slot and noncontacted electromagnetic coupling methods implemented in combination with circular patch results in a directional, left-handed circularly polarized (LHCP) pattern. This article discusses the analysis of several slot shapes that contribute to a good circularly polarized antenna. It also shows that the square slot with truncated edges is more effective in producing circular polarization than the conventional circular and usual square slot. Simulated and experimental results are in good agreement and indicate a ?10-dB S11 and a 3-dB AR bandwidth of about 90 MHz and 25 MHz, respectively.
Author(s): M. I. Sabran, S. K. A. Rahim, P. J. Soh, C. Y. Leow, G. A. E. Vandenbosch
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: The Effect on a Human Heart Model from Dipole Antenna, with an without Shield on SAR and Temperature Increase
Abstract: In this paper, investigate effect of dipole antenna over human heart and a comparative study of temperature increased at heart and specific absorption rate (SAR) without and with different material shields. These structures are modeled and numerically tested by using finite element method (FEM) by using Comsol Multiphysics. The created virtual models using 3D simulation and computation software proved that used shield around human heart reduce the effects of EM fields. The simulation outputs used as measures for this comparative study include the increased temperature and specific absorption rate (SAR), which SAR determines the amount of radiation that human tissue absorb. In addition, study effects of variation of distance of shield from antenna and simulated temperature and SAR.
Author(s): S. I. Zonoori, S. V. Makki, A. Torabi
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
Download Link:Click here to download PDF     File Size: 1829 KB

Title: Optimized Polygonal Slit Rectangular Patch Antenna with Defective Ground Structure for Wireless Applications
Abstract: A novel triple-band polygonal shaped slit rectangular patch antenna with defective ground structure (DGS) is proposed for WLAN and WiMAX applications. The proposed probe-fed antenna consists of a rectangular patch, zig-zag shaped slit, dual T-shaped slits on both sides and circular dumbbell shaped defected ground. The designed antenna can generate three separate resonant frequencies to cover both the 2.45/5.28 GHz WLAN bands and the 3.5 GHz WiMAX bands while maintaining a small overall size of 40 mm x 28 mm x 3.175 mm. The location and dimension of loaded polygonal slit is obtained with the aid of interfacing a genetic algorithm (GA) model with an IE3D simulator. The results obtained from simulated antenna show 5.23% impedance matching bandwidth at 2.29 GHz, 1.14% at 3.5 GHz, 5.17% at 4.64 GHz. The antenna is experimentally tested, which gives good radiation patterns and sufficient antenna gains over the operating bands.
Author(s): S. R. B. Rama, D. Vakula
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Theoretical Approach for the Design of a New Wideband Ku-band Printed Antenna
Abstract: A design of a broadband Ku-band low-cost printed circuit board technology (PCB) antenna is presented in this paper. An approach was developed to enhance the bandwidth of a simple printed patch antenna. The proposed method is, step by step, detailed to discuss the evolution of the antenna geometry and depicts the contribution of the imported changes on the properties achieved each time. A 22% relative bandwidth in Ku-band was obtained for a footprint of 0.4?0×0.6?0 (?0 is the wavelength in the free space). A good agreement between the simulation and the measurement results of the wideband patch was observed, which proves the interest of this approach.
Author(s): A. Harrabi, T. Razban, Y. Mahe, L. Osman, A. Gharsallah
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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Title: Two Element Dielectric Resonator Antenna with Beam Switching
Abstract: A wideband two element rectangular dielectric resonator antenna (DRA) is proposed in this paper. Each DRA element has two excitation strips and four parasitic patches. A wide impedance bandwidth of more than 37% at the center frequency of 1.6 GHz is achieved. The antenna radiation beam can be switched between two positions in elevation plane, i.e., ? = 45° and ? = -45°. The measured antenna gain is found to be more than 6 dB in the whole frequency band of operation. The matching and the radiation characteristics of the designed switched beam antenna are studied and validated by measurements. A very good agreement between the measured and simulated results is observed.
Author(s): M. K. Saleem, M. A. S. Alkanhal, A. F. Sheta
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
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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: 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
Download Link:Click here to download PDF     File Size: 1194 KB

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: Effect of Plasma on Electromagnetic Wave Propagation and THz Communications for Reentry Flight
Abstract: The spacecraft will experience the well-known “blackout” problem when it re-enters into the Earth’s atmosphere, which results in communication failures between the spacecraft and the ground control center. It is important to study the effect of the plasma on electromagnetic wave (EMW) propagation. The properties of EMW propagation in plasma based on theoretical analysis have been studied in this paper, which indicate that communications using terahertz (THz) wave is an alternative method for solving the blackout problem. The properties of 0.22 THz EMW propagation in plasma have been studied experimentally with shock tube, and the experimental results are in good agreement with the theoretical ones. Both the theoretical and experimental results indicate that communications using THz wave is an alternative and effective way to solve the blackout problem.
Author(s): L. Zheng, Q. Zhao, X. J. Xing
File Type: Journal Paper
Issue:Volume: 30      Number: 11      Year: 2015
Download Link:Click here to download PDF     File Size: 462 KB