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Title: ACES Journal January 2017 Cover
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: ACES Journal January 2017 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: ACES Journal January 2017 Full
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Mathematical Model for Calibration of Potential Detection of Nonlinear Responses in Biological Media Exposed to RF Energy
Abstract: An efficient way to test for potential unsymmetrical nonlinear responses in biological tissue samples exposed to a microwave signal is to observe the second harmonic in a cavity resonant at the two frequencies, with collocated antinodes. Such a response would be of interest as being a mechanism that could enable demodulation of information-carrying waveforms. In this work, an electric circuit model is proposed to facilitate calibration of any putative nonlinear RF energy conversion inside a high quality-factor resonant cavity with a known nonlinear loading device. The first and second harmonic responses of the cavity due to loading with the nonlinear and lossy material are also demonstrated. The results from the proposed mathematical model give a good indication of the input power required to detect any very weak second harmonic signal in relation to the sensitivity of the measurement equipment. Hence, this proposed mathematical model will assist in determining the level of the second harmonic signal in the detector as a function of the specific input power applied.
Author(s): C. H. See, R. A. Abd-Alhameed, A. F. Mirza, N. J. McEwan, P. S. Excell, Q. Balzano
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Time-Domain Electromagnetic Inversion Technique for Biological Tissues by Reconstructing Distributions of Cole-Cole Model Parameters
Abstract: The Cole-Cole (C-C) models have been frequently used for a precise description of the dispersion characteristics of biological tissues. One of the main difficulties in the direct reconstruction of these dielectric properties from time-domain measurements is their frequency dependence. In order to overcome this difficulty, an electromagnetic (EM) inversion technique in the time domain is proposed, in which four kinds of frequency-independence model parameters, the optical relative permittivity, the static conductivity, the relative permittivity difference, and the relaxation time, can be determined simultaneously. It formulates the inversion problem as a regularized minimization problem, whose forward and backward subproblems could be solved iteratively by the finite-difference time-domain (FDTD) method and any conjugate gradient algorithm, respectively. Numerical results on two types of stratified C-C slabs, with smooth and discontinuous parameter profiles, respectively, confirm the performance of the inversion methodology.
Author(s): G. Liu
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Novel Extraction Method of Inductance Parameter for Nonuniform Transmission Line in Anisotropic Dielectric
Abstract: Since the parameters of transmission line can affect the signal integrity and electromagnetic compatibility directly in high frequency circuit, and there is lack of researches in the field of solving the inductance parameter of nonuniform transmission line in anisotropic dielectric, a novel method has been proposed in this paper to solve this problem. The new method uses filament division to establish the dispersion model of nonuniform transmission line, and formulates the filament division principle based on Biot-Savart Law and skin effect. Then it develops the Ampere loop integral dyadic equations and the closed circuit dyadic impedance matrix equation with direction factor in frequency domain based on electromagnetic quasi-static (EMQS). To obtain the corresponding magnetic field direction factor, the relative position of filaments in geometric space is analyzed. Finally, the inductance parameters are obtained by the impedance matrix equation. The correctness of proposed method is verified by applying to uniform transmission line model. Then the new method is applied to the calculation of two nonuniform transmission line models which filled in free space and anisotropic dielectric respectively. The inductance parameters and frequency dependency solved by different methods are compared, showing accuracy and validity of the proposed method. Besides, the new method can be applied to various transmission line structures and different anisotropic dielectric.
Author(s): Y. Sun, X. Wang
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: The Investigation of Substrateís Dielectric Properties for Improving the Performance of Witricity Devices
Abstract: In designing a better Witricy device, there are several parameters that contribute to the improvement of efficiency. In this article, the substrate characteristics, which gaining less attention despite their potential for the improvement of Witricity performance are thoroughly studied. The characteristics such permittivity and loss tangent that very common in microwave design are investigated. The investigation has proven that RO 3010 substrate composed of ceramic-filled Polytetrafluoroethylene (PTFE) composites is the best material for the optimal Witricity performance, independent of the spiral coilís number of turns. This is due to its high-energy storage capacity obtained from the real permittivity, and roughly low loss factor and tangent loss. Hence, the Rogers RO 3010 substrate is proposed in this study as it performs reliable 50% to 74% coupling efficiency with the varied number of spiral coil turns.
Author(s): M. H. M. Salleh, N. Seman, R. Dewan
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Assessment of Kapton-based Flexible Antenna for Near Field Wireless Energy Transfer
Abstract: This letter presents the design of a flexible highly efficient antenna for Wireless Energy Transfer (WET) at 13.56 MHz. The proposed antenna uses very thin kapton, with a thickness of 25 ?m as a substrate, and an 18 ?m layer of copper as the conductive material. The 40 mm x 40 mm 6 loop antenna produces almost 90% ETE (energy transfer efficiency) and a bandwidth (BW) of almost 4 MHz for inductive wireless communications. This flexible antenna is suitable for use in small mobile devices, for wireless charging and communication purposes at the NFC operating frequency. In addition, kapton offers very high durability, high mechanical strength, and unique distortional resistance to harsh environments and corrosive aqueous etchants, in this way increasing the reliability of the antenna.
Author(s): M. H. Misran, S. K. Abdul Rahim, A. A. Eteng, G. A. E. Vandenbosch
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Determination of Reverse-Current Coil Turns Layout to Mitigate Over-Coupling in Resonant Inductive Power Transfer Links
Abstract: The transfer efficiency of two-coil resonant inductive power transfer links is known to significantly degrade with a reduction of the coil distance, due to an over-coupling at shorter distances. In this work, a simple technique is introduced to determine the spatial layout of reverse-current coil turns, which suppresses the overcoupling- induced transfer efficiency drop. By employing the spatial layout of reverse-current turns as a design parameter, the proposed method provides more generality in its implementation compared to other reverse-current turn methods. Simulation and experimental results validate the method, suggesting a potential for distanceinsensitive implementations.
Author(s): A. A. Eteng, S. K. A. Rahim, C. Y. Leow, B. W. Chew, G. A. E. Vandenbosch
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: A Data Collection Method Based on the Region Division in Opportunistic Networks
Abstract: The popularity of wearable devices and smart phones provide a great convenience for large-scale data collection. Owing to the non-uniform distribution of mobile sensors, the data quantity collected from different regions has a wide variation. So we design the region division algorithm that divides area into different density grades and sets appropriate sampling frequency on different regions. Furthermore, we propose Circle of Time Slice (CoTS) and Cardinal Number Timing Method (CNTM) to solve the sampling error when nodes move from one area to another. On this basis, we propose the Data Collection Algorithm Based on the Sampling Frequency (DC-BSF) to reduce the data redundancy. Simulations demonstrate that the method proposed in this paper can reduce data redundancy under the condition of achieving high coverage.
Author(s): Y. Ma, S. Zhang, C. Lin, L. Li
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Design of Parabolic Reflector Antenna with Two Directional Cosecant- Squared Pattern Using Curve-Deformation Equations
Abstract: A Ka-band doubly curved reflector antenna for a warning radar system for the road was designed based on the curve-deformation equations. This antenna requires a cosecant-squared radiation pattern in the vertical and horizontal planes. Using curve-deformation equations, the shaped reflector antenna was designed to satisfy the desired beam pattern. The curve-deformation equations include the parameters which determine the shape of the curve, and these parameters are obtained by the optimization process. The simulated result shows the designed antenna satisfies the specifications of the antenna for the road radar system.
Author(s): K.-B. Kong
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
Download Link:Click here to download PDF     File Size: 2237 KB

Title: Compact Broad Band-Stop Filter with Circular Fractal-Shaped Stubs for X-Band Radar Applications
Abstract: In this letter, we use the fractal structures to design a novel compact band-stop filter with prominent cut-off sharpness and wide stop-band for X-band applications. By cutting five U-shaped slots on the ground plane and by inserting five Fractal- Shaped stubs in the microstrip transmission line, the proposed structure is created hence a constant and flat impedance bandwidth at the X-band can be produced. The operating frequencies of the filter can be easily controlled by changing the protruded fractal-shaped stubs dimensions, without changing the area taken by the structure. The experimental results show good agreement with simulation results and demonstrate that excellent stop-band performance could be obtained through the proposed band stop filter.
Author(s): M. Pourbagher, J. Nourinia, C. Ghobadi
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: RCS Validation of Asymptotic Techniques Using Measured Data of an Electrically Large Complex Model Airframe
Abstract: This paper validates the accuracy with which various asymptotic techniques including RL-GO and SBR can calculate the RCS of an electrically large complex airframe. This target has a maximum electrical length of 106?. Two CEM packages are utilized namely, CST MWS and FEKO. The simulated RCS results are compared to measured RCS data, obtained in a compact range. The effect of the 3D CAD model accuracy on the simulation accuracy is also investigated. Comparisons between simulated and measured RCS data are provided using RCS plots and ISAR images.
Author(s): C. Pienaar, J. W. Odendaal, J. Joubert, J. C. Smit, J. E. Cilliers
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
Download Link:Click here to download PDF     File Size: 2608 KB

Title: A Novel UWB Monopole Antenna with Controllable Band-Notch Characteristics
Abstract: A novel microstrip monopole antenna for Ultra Wide Band applications with switchable bandnotch function is presented. For this purpose, elliptical radiator and a half circular shape ground plane are modified. Using these modifications, including a rectangular and an arc-shaped slots on ground plane and a complex form of slot, etched on the patch, new resonances are excited and hence bandwidth is enhanced. In addition, by adding one rectangular step to patch, wide fractional bandwidth of more than 124% (2.7-11.61 GHz), defined by 10 dB return loss is achieved, in following part effects of the rectangular step is investigated. The rejection of 3.01-3.9 GHz, WiMAX and 5.07-6 GHz, WLAN bands is achieved using small connections as switches across the circular slot and rectangular arm on the radiation patch in specific positions. The total size of antenna is only 21◊26 mm2. Parametric simulation of the proposed modifications and measurement results of the manufactured antenna are presented and discussed.
Author(s): N. Tasouji, J. Nourinia, C. Ghobadi, F. Mirzamohammadi
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: A Novel Compact Polarization Diversity Ultra-Wideband MIMO Antenna
Abstract: A very compact modified simple structure Ultra-Wideband (UWB) antenna with a size of 18 mm by 30 mm is presented for polarization diversity applications. The antenna employs two orthogonal monopole antenna to achieve polarization diversity over the UWB. The antenna was fabricated to study the performance such as S-parameters, radiation pattern, radiation efficiency, peak gain, envelope correlation coefficient and group delay. The measured results demonstrated that the proposed antenna has not only UWB (147.96% impedance bandwidth) but also good isolation less than about -25 dB. Moreover, the system fidelity factor is sufficient for pulse transmission with average 89.6% and 85.3% for ports 1 and 2, respectively. Furthermore, a low envelope correlation coefficient of less than 0.001 occurred, too. All these features show that the proposed UWB MIMO antenna can meet the requirement of MIMO/diversity of communication applications well.
Author(s): S. Karamzadeh
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Dual-Band Wide-Angle Circularly-Polarized Microstrip Antenna by Ferrite Ring Inserted in Its Cavity Domain
Abstract: In this paper coaxially-fed circular microstrip patch antenna with ferrite ring in its cavity domain is presented in order to obtain dual-band circularlypolarized antenna in X-band having wide angle axial ratio in both bands. A mode matching approach is used to see the effects of each mode on input impedance of the antenna and is validated numerically by finite element method. The theoretical calculations for input impedance are in good agreement with full-wave simulation. The scattering and radiation parameters of the antenna are investigated. The antenna patch radius and height are 8 and 1 mm, respectively. The ferrite ring was made of yttrium iron garnet (YIG) and the substrate of antenna is Rogers RT5880. In the first band the antenna has 7 dB gain and the ratio of Copol/Xpol is about 24 dB and in the second band has 5 dB gain and the XPD, i.e., the ratio of Copol to Xpol is about 20 dB.
Author(s): F. R. Rostami, G. Moradi, R. S. Shirazi
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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Title: Computationally Efficient Technique for Wide-Band Analysis of Grid-Like Spatial Shields for Protection Against LEMP Effects
Abstract: This paper introduces a heterogeneous CPU+GPU co-processing implementation of the method of moments (MoM) for broadband full-wave electromagnetic analysis of grid-like spatial shields for protecting structures against LEMP effects. Broadband capacity of the approach is achieved through supporting MoM by adaptive frequency sampling and implicit rational interpolation of the observed quantity via Stoer- Bulirsch algorithm. The overall application performance is increased by hardware acceleration, i.e., by employing CPU+GPU co-processing. Sample numerical results for a lightning protection system directly hit by lightning show that reliable rational interpolation can be done at substantially reduced computational effort compared to that of conventional uniform sampling, and the CPU+GPU co-processing offers additional noticeable speedup over the CPU single-thread implementation of the method.
Author(s): A. Karwowski, A. Noga, T. Topa
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
Download Link:Click here to download PDF     File Size: 1942 KB

Title: Shape Reconstruction of Three Dimensional Conducting Objects Using Opposition-Based Differential Evolution
Abstract: In this paper, shape reconstruction of three dimensional conducting objects using radar cross section (RCS) of the scatterer and opposition-based differential evolution is investigated. The shape of the scatterer is modeled with nonuniform rational B-spline (NURBS) surfaces composed of more than one Bezier patches. NURBS are piecewise polynomial with unknown coefficients that are determined in the procedure of shape reconstruction. Opposition-based differential evolution (ODE) is then employed as an optimization tool to find the unknown coefficients. Physical optics approximation is used to predict RCS of the large conducting scatterer in various directions and at multiple frequencies. The effect of noise is also considered in the inverse process.
Author(s): M. Maddahali, A. Tavakoli, M. Dehmollaian
File Type: Journal Paper
Issue:Volume: 32      Number: 1      Year: 2017
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