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Title: ACES November 2011 Full Journal
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 5231 KB

Title: ACES November 2011 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1444 KB

Title: Efficient Multilevel Compressed Block Decomposition for Large-Scale Electromagnetic Problems using Asymptotic Phasefront Extraction
Abstract: A large dense complex linear system can be obtained when solving an electromagnetic scattering problem with the surface integral equation approach. To analyze the large dense complex linear system efficiently, the multilevel compressed block decomposition (MLCBD) is used to accelerate the matrix-vector multiplication operations. Although the MLCBD is efficient compared with the direct method of moments, it is still less efficient for the large-scale electromagnetic problems. Therefore, an efficient version of MLCBD is proposed in this paper. It utilizes the asymptotic phasefront extraction (APE) to reduce the exorbitant dependence on computer storage and solution time in the MLCBD for analyzing the large-scale electromagnetic problems. The numerical results demonstrate that the APE combined with MLCBD is much more efficient than conventional MLCBD for analyzing the large-scale electromagnetic scattering problems.
Author(s): Z. N. Jiang, R. S. Chen, Z. H. Fan, S. G. Shen, X. Q. Hu
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1136 KB

Title: Electromagnetic Scattering by Arbitrary Shaped Three-Dimensional Conducting Objects Covered with Electromagnetic Anisotropic Materials
Abstract: In this paper, the equivalent dipole-moment method (EDM) is extended and applied in the analysis of electromagnetic (EM) scattering by the arbitrarily shaped perfect electric conductor (PEC) targets coated with EM anisotropic media. At first, the volume integral equation and surface integral equation are built in the EM anisotropic material region and on the conducting surface, respectively. Then, the method of moments (MoM) is used to convert the integral equation into a matrix equation and the EDM is employed to reduce the CPU time of the matrix filling procedure. Numerical results are given to demonstrate the versatility of the proposed approach in handing with the EM scattering by arbitrarily shaped PEC targets coated with EM anisotropic media.
Author(s): X. Deng, C. Gu, Y. Zhou
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1132 KB

Title: Scattering Pattern Calculation for Large Finite Arrays using the Element-Varying Active Element Factor Method
Abstract: In this paper, an efficient approach for calculating the far field pattern of one-dimensional (1-D) and two-dimensional (2-D) finite patch arrays is proposed. Based on the active element factor (AEF) defined specifically for scattering problems, this proposed method takes into account the effects of mutual couplings and array edges. From the induced current distribution on an array with odd or even elements, the array is divided into different parts and neglects the weak mutual coupling affected by far elements for each part. Thus, the element-varying AEF method changes a large array problem into a superposition of various simplified subarray problems. Three examples verify the accuracy and efficiency of the proposed method. Furthermore, the results show that the proposed method with the element-varying AEF technique has the ability to solve the scattering problems of rather large arrays whereas other methods become incapable due to computer hardware limitations.
Author(s): Q. Li, W. Shao, H. Li
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1198 KB

Title: Comparison of Modeling Approaches for Prediction of Cleaning Efficiency of the Electromagnetic Filtration Process
Abstract: The present study aims at applying different methods for predicting the cleaning efficiency of the electromagnetic filtration process (?) in the mixtures of water and corrosion particles (rust) of low concentrations. In our study, artificial neural network (ANN), multivariable least square regression (MLSR), and mechanistic modelling approaches were applied and compared for prediction of the cleaning efficiency for the electromagnetic filtration process. The results clearly show that the use of ANN led to more accurate results than the mechanistic filtration and MLSR models. Therefore, it is expected that this study can be a contribution to the cleaning efficiency.
Author(s): Z. Yildiz, M. Yuceer, T. Abbasov
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1271 KB

Title: Lowpass and Bandpass Filter Designs Based on DGS with Complementary Split Ring Resonators
Abstract: We present novel designs of compact lowpass filters (LPF) and bandpass filters (BPF) based on defected ground structures (DGS) using two complementary split ring resonators (CSRR) that are etched in the ground plane. The geometries of the two CSRRs, of unequal areas, are optimized for a LPF with sharp cutoff and wide stop band. For the design of the BPF, a gap capacitor is added in series with the main transmission line and the two or three etched CSRRs are designed to achieve a given bandwidth, and a wide rejection band. Simulation results on the SEMCAD-X software are compared with circuit models and measurements on fabricated lowpass and bandpass filters.
Author(s): G. E. Al-Omair, S. F. Mahmoud, A. S. Al-Zayed
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1323 KB

Title: Full-Wave Analysis of Loaded Dipole Antennas using Mode-Matching Theory
Abstract: The influence of the material inclusions on the input impedance of the loaded dipoles excited by a delta function is analytically investigated. Novel and accurate analytical expressions for the input impedance of the loaded dipoles are proposed based on the mode matching technique. The boundary conditions are also enforced to obtain several simultaneous equations for the discrete modal coefficients inside the radiating region. Study of the input impedance of the whole multilayered structure is accomplished by the cascade connection of mediums as characterized by their constitutive parameters. The derived formulas are successfully validated through a proper comparison with the results obtained with the commercial software CST Microwave Studio.
Author(s): A. Jafargholi, M. Kamyab
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1150 KB

Title: Analysis of Microstrip Antennas using The Volume Surface Integral Equation Formulation and the Pre-Corrected Fast Fourier Transform Method
Abstract: A rigorous and effective analysis based on the volume-surface integral equation (VSIE) formulation and pre-corrected-fast Fourier transform method (P-FFT) is presented for the problems of finite microstrip antennas which are modeled by combined conducting and dielectric materials. Several typical microstrip antennas and conformal microstrip antenna arrays are reconsidered; the comparisons of results from calculation and measurement validate the algorithm. Different feed methods are also considered to excite the antennas and conformal arrays. All the problems could be solved on a small computer with high efficiency and good precision.
Author(s): K. Xiao, Y. Li, F. Zhao, S. Chai, J. Mao
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1516 KB

Title: Effect of Curvature on the Performance of a Cylindrically-Conformal Cavity-Backed E-patch Antenna
Abstract: The behavior of a cavity-backed Epatch antenna placed conformal to a cylindrical conducting surface is explored through simulations and experiment to determine the effects of curvature on antenna performance. It is shown that introducing a cavity backing reduces the bandwidth of an E-patch, but that the curvature of a conformal antenna partly compensates for the loss of performance. It is further shown that the curvature of a conformal antenna strongly affects both the co- and cross-polarization gain patterns.
Author(s): C. M. Gardner, L. C. Kempel, J. A. Hejase, R. O. Ouedraogo, S. W. Schneider
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1648 KB

Title: Optimized Design of Cylindrical Corner Reflectors for Applications on TV Broadband Antennas
Abstract: The increasing of digital TV channels throughout the UHF band leads to use antennas with greater directive gain and improved response in higher bandwidth. For this purpose, in this paper an optimized design for a cylindrical corner reflector is presented. A comparative study between the radiation patterns in the UHF band for different commonly used reflectors is therefore carried out. Based on this study, a modified Yagi- Uda antenna with a cylindrical corner reflector has been suggested and implemented.
Author(s): J. A. Romo, I. F. Anitzine, J. Garate
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1591 KB

Title: A New Left-Handed Metamaterial Structure Based on Split-Triangle Resonators (STRs)
Abstract: In this paper, small compact split triangle-resonators (STRs) with left-handed metamaterial (LHM) properties is proposed. The parameters of this new resonator are found by using the transfer matrix method and Nicholson- Ross-Weir method. Our results indicate that this structure could be used to realize the refractive index medium. Using the x-direction of the electromagnetic propagation wave, a simultaneous negative permeability and permittivity is obtained. The origin of the negative refractive index is a resonance due to the internal inductance and capacitance of the structure. In addition to simultaneous permittivity and permeability, the copper resonator has the advantage of being positioned on only one side of the FR4 substrate.
Author(s): M. A. A. Abessolo, N. Aknin, A. El Moussaoui
File Type: Journal Paper
Issue:Volume: 26      Number: 11      Year: 2011
Download Link:Click here to download PDF     File Size: 1178 KB