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Title: ACES Journal January 2015 Cover
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: ACES Journal January 2015 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: ACES Journal January 2015 Full
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Parallel Model Order Reducation for Sparse Electromagnetic/Circuit Models
Abstract: This paper describes a parallel Model Order Reduction (MOR) technique for Linear Time Invariant (LTI) electromagnetic/circuit systems with sparse structure. The multi-point Krylovsubspace projection method is adopted as framework for the model order reduction and a parallelization strategy is proposed. More specifically, a multi-point version of the wellknown PRIMA algorithm is proposed, which is parallelized with respect to the computation of the error between the original model and the reduced one. The number of moments to be matched for any expansion point is chosen adaptively as well. The numerical results show that the proposed parallelized MOR algorithm is able to preserve the accuracy of the reduced models while providing a significant compression and a satisfactory speedup with respect to the sequential one.
Author(s): G. D. Luca, G. Antonini, P. Benner
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: A Spherical Harmonic Expansion Method for Accelerating the Interface Between the NEC-REF and NEC-BSC Codes
Abstract: A spherical harmonic expansion is proposed to provide a more efficient interface between a reflector antenna simulation code and an Uniform Geometrical Theory of Diffraction (UTD) ray tracing code. The principal bottleneck is a large number of dipole sources. As a consequence, a large number of dipole sources lead to a large number of ray traces, which increases the computational times in the UTD code. We propose to use a spherical harmonic expansion of the reflector fields as an efficient interface. This method saves significant computational times in the UTD code provided that the number of dipole sources per cell is large.
Author(s): J. T. Quimby, R. Thompson, R. J. Marhefka, J. D. Rockway
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Resolution Analysis of a Polymethylmethacrylate Tapered Probe in Near-Field Terahertz Imaging
Abstract: A Polymethylmethacrylate (PMMA) rectangular tapered probe with metal coating on the sides is analyzed as a near-field imaging probe at 100 GHz in Ansoft High Frequency Structure Simulator (HFSS). Normally, highly resistive silicon and sapphire, which are costly, are used as a near-field probe due to their low loss and high permittivity. PMMA near-field probe is usually used in Scanning Near-field Optical Microscopy (SNOM), which is made from PMMA optical fibers. We propose for the first time to use PMMA as a near-field probe in millimeter and Terahertz wave scanning near-field imaging applications. The geometrical optimization of the tapered probe is carried out on the basis of different coupling methods. The beam shape merging from the end of the tapered tip is analyzed. The operation efficiency of two-side tapered and four-side tapered probes has been compared in view of the fabrication technique. A knife edge is simulated in HFSS to define the lateral resolution. Longitudinal resolution is discussed through setting a stair step shaped sample. A high lateral resolution around the end of the probe size can be achieved and even higher longitudinal resolution. The impact of the tip-sample distance and the lateral resolution are clearly illustrated via simulations. Experiments are carried out using a two-side tapered probe provided with an aluminum coating. The resolution is defined by scanning a PMMA board which was half coated with aluminum.
Author(s): B. Zhu, G. He, J. Stiens, J. V. Erps, W. Ranson, C. D. Tandt, H. Thienpont, R. Vounckx
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Efficient and Accurate Analysis of a Substrate Integrated Waveguide (SIW) Rat-Race Coupler Excited by Four U-Shape Slot-Coupled Transitions
Abstract: In this paper, the bandwidth of one SIW rat-race (hybrid ring) coupler has been increased up to 30% by four U-shape slot-coupled transitions without disadvantages due to transmission line loss, radiation and design complexity. The SIW coupler structure has been analyzed by the mode matching method that uses the cylindrical vector expansion to minimize computational time and memory occupation. Throughout 11-15 GHz bandwidth, return loss and isolation as well as phase differences in output ports have been presented. It is observed that the numerical results are in good agreement with simulation and experimental measurement.
Author(s): R. Dehdasht-Heydari, K. Forooraghi, M. Naser-Moghadasi
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: An Integral Equation-Based Approach to Analyzing Symmetrical Electromagnetic Models Through Decomposition and Recomposition of Excitation Vectors
Abstract: In this paper, an Integral Equationbased Simplification Method (IE-SM) is presented for the efficient analysis of the symmetrical electromagnetic model. The proposed approach stems from the decomposition and recomposition of any arbitrary excitation sources into a set of independent vectors which induce a symmetrical current distribution. Compared to the Conventional Integral Equation (CIE) method for modeling an entire structure, this simplification method not only saves computation resources and time by reducing the number of unknowns, but also maintains the computation accuracy. In addition, this method has a simple integral equation formulation, so it can be easily accelerated with fast algorithms and integrated into the existing Method of Moments (MoM) codes. Numerical examples show that the proposed method demonstrates both satisfactory accuracy and efficiency with less computational complexity.
Author(s): J. Su, Z. Li, Y. Yang, G. Lu
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Ultra Wideband Microwave Ten-Port Reflectometer
Abstract: This paper describes and simulates the Ultra Wideband (UWB) Ten-Port Reflectometer (TPR). It is based on the concept of well-known sixport structure so that numbers of measuring ports are increased to eight in order to improve reliability and accuracy as well. This article presents UWB (2 GHz to 12 GHz) reflectometer using Rectangular Waveguide (RWG). It is proved that increasing numbers of measuring ports leads to improving accuracy and reliability of structure so that each port with corresponding port help to make wideband reflectometer as well as having reliable and robust structure. This prototype of ten-port reflectometer is simulated by Agilent ADS and using RWG that has more bandwidth, less loss and high Q-factor than other common transmission lines, say microstrip, SIW and CPW.
Author(s): A. Askarian, G. Moradi
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
Download Link:Click here to download PDF     File Size: 468 KB

Title: Modified Antipodal Vivaldi Antenna with Shaped Elliptical Corrugation for 1-18 GHz UWB Application
Abstract: We present to antipodal tapered slot antennas: one with elliptical strips termination and the other modified with elliptical shaped corrugations. Compared to the other, the corrugated antenna uses elliptical slots loading to improve the gain by up to 1.9 dB over operational bandwidth 0.8-18 GHz. It also improves the front to back lobe ratio. The simulated frequency and time domain results are in good agreement with measured performance of both antennas. Experimental results verify a fidelity factor greater than 0.86 for both antennas by transmitting 30ps (3-18 GHz) Ultra-Wideband (UWB) pulses.
Author(s): M. A. Ashraf, K. Jamil, A. R. Sebak, M. Shoaib, Z. Alhekail, M. Alkanhal, S. Alshebeili
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
Download Link:Click here to download PDF     File Size: 734 KB

Title: Bandwidth Enhancement of Small Square Monopole Antenna with Dual Band Notch Characteristics Using U-Shaped Slot and Butterfly Shape Parasitic Element on Backplane for UWB Applications
Abstract: In this study, a dual band notch microstrip antenna for UWB applications has been presented. The antenna consists of a stepped patch with U-shaped slot, two rectangular shaped slots in the ground plane and a butterfly shaped parasitic backplane element structure. By inserting two rectangular shaped slots in the ground plane, much wider impedance bandwidth can be produced. This modification significantly improves the antennaís impedance bandwidth by 155% which covers the entire UWB bandwidth range and even more. In order to generate single band notch characteristic, a butterfly shaped conductor backplane structure is utilized on the ground plane side of the substrate. In addition, by cutting a U-shaped slot on the radiating patch, a dual band notch function is achieved. The measured frequency results show an impedance bandwidth of 2.35-13 GHz for a Voltage Standing Wave Ratio (VSWR) less than 2 with two eliminated bands placed at 3.25-3.85 GHz and 4.9-6.2 GHz, which reject the Wireless Local Area Network (WLAN) band, WiMAX band, and a major part of the C-band. The measured E-plane and H-plane radiation patterns show a very good correlation with the requirements of UWB applications.
Author(s): P. Beigi, J. Nourinia, B. Mohammadi, A. Valizade
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Analysis for Three-Dimensional Curved Objects by Runge-Kutta High Order Time-Domain Method
Abstract: In this paper, a Conformal RungeKutta High Order Time Domain (C-RK-HOFDTD) method has been presented and applied to model and analyze in curved objects. The general update equations of the method and the Effective Dielectric Constant (EDC) have been derivated. The scattering of the cylinder and ellipsoid are used to validate the proposed method, and the results are shown that the scheme provides the better accuracy than the HO-FDTD and other higher order methods.
Author(s): M. Zhu, Q. Cao, L. Zhao, Y. Wang
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
Download Link:Click here to download PDF     File Size: 200 KB

Title: A Novel Compact CPW-Fed Antenna with Circular Polarization Characteristics for UWB Applications
Abstract: A novel compact antenna with Circular Polarization (CP) characteristics is presented. The antenna structure includes an asymmetrical rectangular radiating patch from which a semi-circle shaped slot is cut. A 50 ? CoPlanar Waveguide (CPW) feed line with two rectangular slots feeds the antenna. Two inverted L-shaped strips and also two spiral shaped slots are embedded on opposite corners of the ground plane to further enhance the antenna bandwidth and also generate the circular polarization property. The antenna is printed on a compact size FR4 substrate with the total dimensions of 20◊20◊1.6 mm3 . The proposed antenna operates over the frequency range of 3-14.5 GHz for VSWR<2 and exhibits CP in 5.35-7.65 GHz (35%).
Author(s): F. Azamian, M. N. Azarmanesh, C. Ghobadi
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Analysis of Square Coaxial Line Family
Abstract: In this paper, the Equivalent Electrodes Method (EEM) has been proposed for the analysis of square coaxial lines family. Lines with single and two layer perfect or imperfect medium have been analyzed. The capacitance per unit length of these lines has been calculated. The results obtained by EEM have been compared with those reported in the literature, obtained by other methods, and those obtained by using software package COMSOL Multiphysics. Also, with the aim of comparison of the results, capacitance measurements based on a high resolution CDC (Capacitance to Digital Converter) have been realized. All results obtained have been found to be in very good agreement.
Author(s): A. M. Milovanovic, B. M. Koprivica, A. S. Peulic, I. L. Milankovic
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Design and Analysis of an Interior Continuous Magnetic Gear Box Using Finite Element Method
Abstract: Magnetic gears offer important potential benefits compared with mechanical gears such as reduced maintenance, improved reliability, inherent overload protection, and physical isolation between the input and output shafts. This paper presents the design and analysis of a novel structure of magnet gear, which named Interior Magnetic Gear (IMG) using neodymium-iron-boron magnets for the applications in which continuous ratio of gear box is useful such as wind generators, electric vehicles and etc. The analysis is performed by Finite Element Method (FEM) to predict output torque, speed and magnetic field distribution inside the gear box. The IMG made up of an inner rotor and an outer rotor. The inner rotor is similar to the rotor of a 3 phase wound rotor induction motor and the outer rotor consists of 6 PM poles. Both the inner rotor and the outer rotor can be employed as a low/high speed rotating part. The interior arrangement of PMs result many advantage such as low torque ripple. The simulation and analytical results are in good accord.
Author(s): B. Majidi, J. Milimonfared
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Novel Design of UWB Band-Stop Filter (BSF) Based on Koch Fractal Structures
Abstract: In this paper, a novel design of compact microstrip Ultra-Wideband (UWB) BandStop Filter (BSF) for wireless applications is proposed. The proposed BSF structure is based on Koch fractal geometry where its third iteration operates over a very wide bandwidth and improves the impedance matching. The microstrip filter configuration consists of a transmission line with pairs of Koch fractal Radial Stubs Loaded Resonators (RSLRs), and a modified ground plane with triple modified Defected Ground Structures (DGSs). Operation frequencies of the filter can be easily controlled by changing the iteration of embedded fractal structure. The DGS slots evolved from Photonic Band Gap (PBG) is embedded to achieve a good impedance matching and the required filterís characteristics. The proposed BSF has a flat rejected-band characteristic around of 3.1-10.6 GHz with an insertion loss which is larger than 45 dB and a return loss less than 0.5 dB at the centre of the band-stop frequency range. An excellent agreement between measured and simulated was obtained. The proposed microstrip filter is fabricated on a Rogers RT/Duroid 5880 substrate with a relative dielectric constant of 2.2 and has a small size of 10◊15◊0.635 mm3 . The proposed filter configuration is and can be integrated into any UWB system.
Author(s): N. Ojaroudi, Y. Ojaroudi, S. Ojaroudi
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: Parametric Study of Sinc Shaped Monopole Antenna for Wireless Devices
Abstract: In this work, a Sinc shaped printed monopole antenna is proposed for wireless devices. The radiating element is a strip monopole configuration folded in the shape of a Sinc function where the radiating element is an extension of 50 ? microstrip line. The proposed antenna not only represents a compact configuration but is easier to design and feed. Several configurations of truncated Sinc(2x) monopole geometry are taken into consideration to show the resonance behavior at single, two or more than two frequencies for multifrequency operation. The detailed parametric study has been carried out in terms of several truncated Sinc configurations, ground plane size, feed gap and Sinc strip length to achieve the desired band of operation. The design formula is also presented for the proposed monopole antenna. Finally, a prototype model is developed and the simulated results are validated experimentally for a particular configuration. It is seen that the proposed antenna occupies small area, depicts good radiation characteristics and is suitable for wireless devices operating at DCS/PCS/IMT-2000/UMTS frequencies.
Author(s): R. K. Badhai, N. Gupta
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
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Title: SV-Training and Kernel Change Detection Algorithm for the Abrupt Modification in EMI Data for Buried Metallic Target Localization and Identification
Abstract: In this paper, we propose a new method to identify and to locate buried metallic object in ElectroMagnetic Induction (EMI) data based on the Kernel Change Detection (KCD) algorithm. The signature of the object in the EMI data is typically of low amplitude. Particularly, in the case where two objects are located at different depths, the amplitude of the deeper buried object is negligible compared to that of the object buried in the first centimeter of the soil. This would result in the fact that, the EMI system can neglect the signature of this object and consequently increases miss rate or False Negative Rate (FNR). The aim of the proposed method is to calculate a decision index for each EMI measurement in a so-called hypotheses space using KCD algorithm. The amplitude of these decision indexes in the case of objects at different depths are in the same range, which make their variance smaller. Indeed, this index will be compared to a threshold for judging the presence or absence of a rupture. The validation of the proposed method is performed by processing real EMI data derived from a series of measurements on real objects.
Author(s): Y. Matriche, S. Moussaoui, M. Feliachi, A. Zaoui, M. Abdellah
File Type: Journal Paper
Issue:Volume: 30      Number: 1      Year: 2015
Download Link:Click here to download PDF     File Size: 466 KB