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Title: ACES July 2010 Full Journal
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 6319 KB

Title: ACES July 2010 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 537 KB

Title: Improvement of Compactness of Lowpass/Bandpass Filter Using a New Electromagnetic Coupled Crescent Defected Ground Structure Resonators
Abstract: This paper introduces a new compact defected ground structure (DGS) low pass filter (LPF) using a crescent shape structure etched in the ground plane. The filter response has improved dramatically by employing coupling of two DGS structures. Furthermore, the transformation to bandpass filter (BPF) is also investigated. The proposed configuration improved the lowpass response by widening the rejection band while significantly reducing the size. The behaviour of the filter has been investigated using HFSS as well as lumped element equivalent circuit model simulations using parallel L-C resonator. The proposed filter has been optimized.
Author(s): M. Al Sharkawy, A. Boutejdar, F. Alhefnawi, O. Luxor
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 968 KB

Title: Computationally Efficient Multi-Fidelity Multi-Grid Design Optimization of Microwave Structures
Abstract: A simple and reliable algorithm for design optimization of microwave structures is introduced. The presented methodology exploits coarse-discretization models of the structure of interest, starting from a very coarse mesh, and gradually increases the discretization density. Each model is optimized using a simple grid-search routine. The optimal design of the current model is used as an initial design for the finer-discretization one. The proposed methodology is computationally efficient as most of the operations are performed on coarse-discretization models. Three examples of microstrip filter designs are given.
Author(s): S. Koziel
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 466 KB

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
Download Link:Click here to download PDF     File Size: 747 KB

Title: Analysis of the Shielding Effectiveness of Metallic Enclosures Excited by Internal Sources Through an Efficient Method of Moment Approach
Abstract: The shielding effectiveness of rectangular metallic enclosures having thin or thick apertures in one of their walls and possibly loaded with conducting bodies is studied in detail for internal electromagnetic sources consisting of electric or magnetic dipoles. The analysis is performed through an efficient integral-equation formulation based on the Method of Moments, which makes use of several numerical tools (acceleration of the enclosure Greenís function evaluation, its interpolation, possible use of entire domain basis functions, etc...) and physicall ybased approximations, critically discussed. Several cases are studied and comparisons with results obtained through different full-wave commercial software confirm the accuracy of the proposed approach and its superior performance in terms of computational time and memory storage.
Author(s): R. Araneo, G. Lovat
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 973 KB

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
Download Link:Click here to download PDF     File Size: 1059 KB

Title: Design and Simulation of Frequency-Selective Radome Together with a Monopole Antenna
Abstract: In this paper, we present a novel axi-symmetric conical FSS radome at S-band and investigate the effect of the FSS radome located in close proximity of a monopole antenna. The strict periodic array of the novel FSS radome was indicated in detail, and the FSS radome together with a monopole antenna was simulated using the Ansoft software HFSS both at the pass and stop bands. The simulated results show that the novel FSS radome has a narrow band-pass response and is prospectively useful for out-of-band RCS control.
Author(s): B. Lin, S. Du, H. Zhang, X. Ye
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 715 KB

Title: Subtraction of Discontinuity Susceptance for WIPL-D Source Modeling
Abstract: WIPL-D does not include a provision for a direct specification of a coaxial line excitation of patch antennas in terms of the incident dominant TEM mode. Instead, such an excitation is approximated by a voltage generator in series with a thin wire, one end of which is connected to the inner conductor of the coax and the other end to a flat shorting cap joined to the outer conductor. The transition from the diameter of the inner conductor to the diameter of the wire gives rise to a spurious capacitive shunt susceptance leading to an error in the calculated antenna input impedance. It is shown that this susceptance can have a significant effect on the WIPL-D calculations of the return loss of narrow band patch antennas. A computational technique is presented for neutralizing this modeling deficiency.
Author(s): H. A. Abdallah, W. Wasylkiwskyj
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 1195 KB

Title: Design of a Meander-Shaped MIMO Antenna Using IWO Algorithm for Wireless Applications
Abstract: Using a MIMO antenna system is a well-known technique to enhance the performance of wireless communication systems. In order to create a MIMO antenna system on a wireless device, two or more antenna elements could be placed in a very small space. Thus, the mutual coupling including radiation pattern coupling between closely arrayed antenna elements causes the decrease of a MIMO antenna performance. It means that we must consider not only the antenna size but also the suitable antenna array method to design the MIMO antenna system. The aim of this research was to design an antenna for a fourchannel multiple input multiple output (MIMO) system that works at 5.8 GHz with consideration of the mutual coupling. The geometry of the antenna is optimized by using Invasive Weed Optimization algorithm to accomplish high degree of isolation. The measurement and simulation results of reflection coefficient, mutual coupling and radiation pattern are presented and discussed.
Author(s): B. Bahreini, A. Mallahzadeh, M. Soleimani
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 710 KB

Title: Iterative Solution of Electromagnetic Scattering by Arbitrary Shaped Cylinders
Abstract: The electromagnetic scattering analysis of geometrically complex structure has played an important role in electromagnetic field theory and practicable applications. The fast and rigorous methods to solve such problem are in great demand. In this work, the Wave Concept Iterative Process (WCIP) combined with a coordinate transformation has been extended to the scattering problems of electromagnetic conducting square cylinder, conducting super-ellipsoid and conducting super-ellipsoid coated with thin dielectric materials. Numerical results illustrate the efficiency of our approach. The radar cross section (RCS) is then reached and compared with the literature.
Author(s): J. Selmi, R. Bedira, A. Gharsallah, A. Gharbi, H. Baudrand
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 470 KB

Title: A Microwave Technique for Detecting Water Deposits in an Air Flow Pipelines
Abstract: A simple microwave method is used to determine thin layers of water inside the air or compressed-air carrying pipes of pneumatic systems. The technique proposed here is based on the shift in the resonant frequency with the changing air-water ratio within the pipe. A calibration chart relating the resonant frequency and thickness of water layer is presented and experimentally verified. Experimental results agreed well with the simulated response, particularly for thin water layers, which are difficult to detect accurately using existing methods.
Author(s): S. I. Sheikh, H. A. Ragheb, K. Y. Alqurashi, I. Babelli
File Type: Journal Paper
Issue:Volume: 25      Number: 7      Year: 2010
Download Link:Click here to download PDF     File Size: 153 KB