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Title: ACES Journal December 2014 Cover
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: ACES Journal December 2014 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: ACES Journal December 2014 Full
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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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: 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: 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: 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: Finite-Element Domain Decomposition Methods for Analysis of Large-Scale Electromagnetic Problems
Abstract: This paper presents an overview of our recent development of domain decomposition methods for finite element analysis of large-scale electromagnetic problems. More specifically, it presents several domain decomposition algorithms based on the Dual-Primal Finite Element Tearing Interconnecting (FETI-DP) method for solving vector wave equations. These algorithms expand the capability and improve the performance of the FETI-DP method by: (1) lifting the requirement of conformal meshes on subdomain interfaces, (2) speeding up the convergence of the iterative solution of the global interface problem, and (3) incorporating appropriate truncation boundaries for more accurate simulation. Numerical results are presented to demonstrate the application, accuracy, efficiency, and capability of these algorithms.
Author(s): M.-F. Xue, J.-M. Jin
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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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: Phi Coprocessor Acceleration Techniques for Computational Electromagnetics Methods
Abstract: In this paper, we introduce the architecture of Intel Xeon Phi coprocessor, programming and acceleration techniques in the computational electromagnetic methods. This paper describes how to develop the acceleration codes based on the Intel Xeon® Phi coprocessors in the parallel format for general computational electromagnetics methods. We also present management of the cores and threads in the Intel Xeon Phi coprocessors to accelerate computational electromagnetics simulations. The Intel Phi coprocessor can be used as a regular CPU and shares the same source codes for Intel Xeon E3 and E5 CPUs with a different compilation option. The examples shown here are for acceleration of the parallel FDTD methods. The Intel Xeon Phi coprocessor is not a GPU and is a general hardware acceleration simulation platform.
Author(s): X. Yang, W. Yu
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: A Simple GPU Implementation of FDTD/PBC Algorithm for Analysis of Periodic Structures
Abstract: Constant horizontal wavenumber approach is a simple method to model Periodic Boundary Conditions (PBC) in the FiniteDifference Time-Domain (FDTD) method proposed for efficient analysis of periodic structures; however, it requires execution of the FDTD simulations many times, each time for a different value of horizontal wavenumber to achieve useful results. Therefore, although each simulation may take a short time to complete, a sweep of simulations still takes a long time and there is a need to employ methods to speed-up the simulations. In this contribution we present an implementation of the FDTD/PBC algorithm using the Compute Unified Device Architecture (CUDA) to run the simulations on Graphics Processor Unit (GPU) devices to speed-up the the FDTD/PBC simulations. We also present a method in which a problem space is extended by one padded cell on each of the four periodic sides. As a consequence, programming is simplified, especially for the GPU code for the field update process at the boundaries, the problem space and efficiency of calculations as well is improved.
Author(s): V. Demir
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
Download Link:Click here to download PDF     File Size: 302 KB

Title: Modeling Resonant Frequency of Rectangular Microstrip Antenna Using CUDA-Based Artificial Neural Network Trained by Particle Swarm Optimization Algorithm
Abstract: Resonant frequency is a vital parameter in designing Microstrip Antenna (MSA). Artificial Neural Network (ANN) based on Particle Swarm Optimization (PSO) algorithm (PSO-ANN) has been used to model the resonant frequency of rectangular MSA. To deal with the problem of the long execution time when training PSO-ANN, its parallel implementation in the Graphic Processing Unit (GPU) environment is proposed in this paper. The presented approach uses the particle behavior parallelization of PSO to accelerate ANN training, and is applied to modeling the resonant frequency of rectangular MSA under Compute Unified Device Architecture (CUDA). Experimental results indicate that compared with CPU-based sequential PSO-ANN, more than 300 times of speedup ratio has achieved in GPU-based parallel PSO-ANN with the same optimization stability. Furthermore, the network error can be significantly reduced with the very limited runtime increment when substantially enlarging the number of particles on GPU side.
Author(s): F. Chen, Y.-B. Tian
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Surface Impedance Absorbing Boundary for Terminating FDTD Simulations
Abstract: An Absorbing Boundary Condition (ABC) for FDTD simulations based on the concept of surface impedance boundary, which is referred to as Surface Impedance Absorbing Boundary Condition (SIABC), is proposed in this paper. It is extremely easy to implement relative to other absorbing boundaries and is found to be sufficient for many practical applications. The formulation of the SIABC is developed and implemented. The performance of SIABC is comparable with that of 10-layers CPML.
Author(s): Y. Mao, A. Z. Elsherbeni, S. Li, T. Jiang
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Biologically Inspired Optimization of Antenna Arrays
Abstract: Modeling biological evolution on a computer began in the 1960s with evolution strategies in Europe and genetic algorithms in the United States. Genetic algorithms were introduced to the antenna community in the early 1990s. Since that time, they have become ubiquitous in computational electromagnetics and standard options on commercial software packages. Other biological design methods based upon biological processes in nature have also been introduced. This article provides an introduction to genetic algorithms, particle swarm optimization, and ant colony optimization. Several examples of antenna array optimization are presented to illustrate the power of these algorithms.
Author(s): P. Rocca, R. L. Haupt
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Robust Adaptive Array Beamforming Based on Modified Norm Constraint Algorithm
Abstract: In order to further improve the performance of the Norm Constrained Capon Beamforming (NCCB) algorithm, a Modified Norm Constraint Capon algorithm (MNCCB) is proposed and investigated in detail. The proposed MNCCB algorithm is realized by exerting an orthogonal projection on the array weight vector and restricting the norm constraint to enhance the array weight vector constraint when Array Steering Vector (ASV) mismatch is large. The simulation results show that the proposed MNCCB can provide stronger robustness against ASV mismatches and can achieve higher output Signal to Interference plus Noise Ratio (SINR), compared with existing adaptive beamforming algorithms.
Author(s): W. Li, X. Mao, W. Yu, Y. Li, C. Yue
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Study on Array Source Stirring Reverberation Chamber
Abstract: Because the structure of transmitting antenna significantly affects the performance of source stirred reverberation chamber, a source stirring reverberation chamber excited by antenna array with a novel configuration is proposed and investigated in this paper. In contrast to traditional source stirring techniques, fewer array elements in reasonable arrangement are employed to use the test space efficiently and ensure the desired field characteristics, such as uniform statistics, isotropic and random polarization. Numerical experiments demonstrate that the statistical distribution of electrical field meets Standard IEC 61000-4-21 and has advantage over the traditional stirring systems.
Author(s): W. Li, C. Yue, W. Yu
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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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: FDTD Implementations of Integrated Dependent Sources in Full-Wave Electromagnetic Simulations
Abstract: The implementation of dependent sources such as: Current Controlled Current Source in full-wave electromagnetic simulation using the Finite-Difference Time-Domain method is introduced. This simple new approach is verified with several numerical examples. In one example, the CCCS is used to implement a circuit with Bipolar Junction Transistor. Good agreement is obtained when the results of the developed FDTD code are compared with those based on analytical solution.
Author(s): K. ElMahgoub, A. Z. Elsherbeni
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
Download Link:Click here to download PDF     File Size: 402 KB

Title: SLF/ELF Electromagnetic Field of a Horizontal Dipole in the Presence of an Anisotropic Earth-Ionosphere Cavity
Abstract: In this paper, the region of interest is a cavity between a spherical and electrically homogeneous earth and an anisotropic homogeneous ionosphere. Both the dipole (Vertical Electric Dipole (VED), Vertical Magnetic Dipole (VMD), or Horizontal Electric Dipole (HED)) and the observation point are assumed to be located on or near the spherical surface of the earth. The approximate formulas are obtained for the electromagnetic field of a vertical magnetic dipole and that of a vertical electric dipole in the presence of an anisotropic earthionosphere cavity, respectively. Based on the results obtained, the approximate formulas are derived readily for the electromagnetic field of a horizontal electric dipole in the presence of an anisotropic earth-ionosphere cavity by using a reciprocity theorem. Analysis and computations in SLF/ELF ranges are carried out specifically.
Author(s): G. Z. Li, T. T. Gu, K. Li
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
Download Link:Click here to download PDF     File Size: 488 KB

Title: Study on Fabry-Perot Antennas Using Dipole Exciters
Abstract: Fabry-Pérot (F-P) cavity antennas with Artificial Magnetic Conductor (AMC) ground planes and Frequency Selective Surface (FSS) superstrates have been investigated in this paper. The method of periodic imaging is used to analyze the cavity antennas, and we can calculate the working frequency and quality factor. One or two dipole antennas are utilized to excite the cavity antennas. The results demonstrate that the gain will be enhanced with the increase of the cavity size, and two exciters in the cavity will improve radiation efficiency obviously.
Author(s): Y. Zhang, W. Yu, W. Li
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Exact Transient Field of a Horizontal Electric Dipole with Double Exponential Excitation on the Boundary Two Dielectrics
Abstract: In this paper, the exact formulas are derived for the time-domain electromagnetic field radiated by a horizontal electric dipole with double exponential excitation along the boundary between two different dielectrics. The transient field components consist of two lateral pulses with the amplitude attenuation factor 2 9 . In particular, the two lateral pulses travel along the boundary in Regions 1 and 2 with different velocities.
Author(s): B. J. Xia, T. T. Gu, W. Dai, K. Li
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Approximation Through Common and Differential Modes for Twist Wire Pair Crosstalk Model
Abstract: In this paper, an advanced approximation method is presented, which separates the twist wire pairs into common and differential modes using the multi-conductor transmission line model. The simulation storage and time cost has been significantly reduced and its accuracy is better than traditional approximation methods. Analyses of dealing with the impedance and admittance and the separation procedure of common and differential modes are presented. In addition, the load dealing methods for terminal and source has also been specified in this paper. Numerical experiments validate the accuracy and listed the storage efficiency and time cost reduction of the proposed method.
Author(s): Y. Sun, Q. Jiang, W. Yu, Q. Zhuo, Q. Li
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
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Title: Hybrid Differential Evolution Particle Filter for Nonlinear Filtering
Abstract: In this paper we propose a novel method for solving the nonlinear problem of the radar target tracking. The algorithm consists of a Particle Filter (PF) which employs the Unscented Kalman Filter (UKF) to generate the importance proposal distribution, and adopts the Hybrid Differential Evolution (HDE) algorithm based on Simulated Annealing (SA) algorithm as the resampling scheme. Firstly, the Importance Distribution (ID) which contains the newest measurements is constructed by the UKF. In addition, the UKF generates proposal distributions that match the true posterior more closely. Secondly, to solve the particle degeneracy and impoverishment phenomenon, the sampling particles are resampled by the HDE algorithm. The mutation and crossover steps of the Differential Evolution (DE) algorithm are executed to generate the trial vectors. Then the selection step is replaced by the Metropolis criterion of the SA algorithm. The proposed algorithm combines the advantages of the SA algorithm with the DE algorithm. It not only has superior estimation performance, but also the convergence speed is fast. Simulation results demonstrate that the proposed algorithm outperforms the standard PF, the Auxiliary Particle Filter (APF), the Regularized Particle Filter (RPF) and the Particle Filter based on Differential Evolution (PFDE).
Author(s): C. Zhang, L. Li
File Type: Journal Paper
Issue:Volume: 29      Number: 12      Year: 2014
Download Link:Click here to download PDF     File Size: 285 KB