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Title: ACES Journal April 2018 Cover
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: ACES Journal April 2018 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: ACES Journal April 2018 Full
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Temperature Rise and SAR Distribution at Wide Range of Frequencies in a Human Head due to an Antenna Radiation
Abstract: Temperature rise and specific absorption rate distribution in a human head due to electromagnetic energy produced by an adjacent antenna are evaluated. An algorithm proposed in this paper provides these distributions at multiple frequencies using a single simulation. The head tissue parameters are used from the available three-term Debye coefficients obtained by the experimental data from 500 MHz to 20 GHz. The proposed algorithm is developed by integrating the Debye model of human head tissues parameters into the finite-difference time-domain method by using the auxiliary differential equation approach along with the use of bioheat equation for specific absorption rate and temperature computations.
Author(s): F. Kaburcuk, A. Z. Elsherbeni
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Modulation of the Antenna-Head Interaction inside a Closed Environment Using MOM-GEC Method
Abstract: The interaction between human head and GSM antenna evaluations are usually conducted in freespace situations but wireless communication devices are frequently used in enclosed environments, such as vehicle, that consist of metallic boundaries. In such fully enclosed or semi-enclosed spaces, human exposure in terms of SAR is closely related to the EM field, which is multiplied, reflected and scattered by the metallic walls of the enclosure. This could lead to complicated resonance effects and affections in the antenna performances. This possible argument of an EM field inside an enclosure has raised serious concerns among the general public. This paper will therefore focus on the impact of dipole antenna modeling the handsets on the SAR distribution inside a cavity modeling the vehicle. Theoretical formulation and simulations are used to study this phenomenon but there is a lot of limitations. Despite, modulation using numerical method are used. A MoMGEC modeling approach is applied to study the behavior of a dipole antenna resonating at 1.8 GHz. First of all, we are interested in studying the convergence of the input impedance. The current and the electric field distribution are simulated. The specific absorption rate (SAR) is examined for several different tissues.
Author(s): H. Messaoudi, T. Aguili
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Design and Measurements of Rectangular Dielectric Resonator Antenna Linear Arrays
Abstract: In this paper, two, four, eight and sixteenelement Rectangular Dielectric Resonator Antenna (RDRA) linear arrays fed by microstrip line have been designed and simulated. The DRA is excited by a vertical strip placed on the middle of the DRA wide side wall through a coaxial probe attached to the microstrip line on the other side of the substrate. The ground plane is sitting directly underneath the RDRA while the microstrip line feeder is at the opposite side of the substrate to avoid the unwanted radiation from the feeder. The simulated and measured 10 dB return loss bandwidth of the antenna arrays are 67.8%, 75%, 73.5%, and 76% for the two, four, eight and sixteen-element arrays respectively. The simulated gain of the single element antenna is about 6 dBi, while it reaches to about 17 dBi for the 16-element array.
Author(s): F. Z. Abushakra, A. S. Al-Zoubi, D. F. Hawatmeh
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
Download Link:Click here to download PDF     File Size: 2467 KB

Title: Design, Fabrication, and Measurements of Extended L-Shaped Multiband Antenna for Wireless Applications
Abstract: This article expounds a multi-band compact shaped antenna, which is based on CPW ground plane. FR-4 with a thickness of 1.6 mm is used as a substrate for the proposed antenna. The proposed antenna is capable of operating at 1.56 GHz for (Global Positioning System), 2.45 GHz (Wireless Local Area Network) and 4.49 GHz (Aeronautical Mobile Telemetry (AMT) fixed services). The efficiency at 1.56, 2.45, and 4.49 GHz is 79.7, 76.9 and 76.7%, respectively. The VSWR of the presented antenna is less than 1.5 at all the desired resonance modes, which confirms its good impedance matching. The performance of the proposed antenna is evaluated in terms of VSWR, return loss, radiation pattern and efficiency. CST®MWS® software is used for simulations. In order to validate the simulation results, a prototype of the designed antenna is fabricated and a good agreement is found between the simulated and measured results.
Author(s): A. Ahmad, F. Arshad, S. I. Naqvi, Y. Amin, H. Tenhunen
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
Download Link:Click here to download PDF     File Size: 2168 KB

Title: A Novel Dielectric Loaded Vivaldi Antenna with Improved Radiation Characteristics for UWB Application
Abstract: In this paper, a compact (40×50×0.8mm3) Vivaldi antenna with trapezoidal corrugation and a triangular director element is proposed for high gain performance. The exponential slot with diamond slot stub is designed to broaden the bandwidth. The measured bandwidth is 11.3 GHz from 2.9 to 14.2 GHz under the condition of Voltage Standing Wave Ratio (VSWR) less than 2. The simulated gain is 5.5-9 dBi at the full bandwidth. The measured gain is 5-7.6 dBi from 3 to 5.8 GHz. In addition, the measured group delay of the proposed antenna is around 2±0.8 ns. The simulated and measured results agree well.
Author(s): H. Zhu, X. Li, L. Yao, J. Xiao
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: A New Compact Planar Antenna for Switching between UWB, Narrow Band and UWB with Tunable-notch Behaviors for UWB and WLAN Applications
Abstract: This paper presents continuously switchable behavior between narrowband (5.5 GHz WLAN), wideband (3-11 GHz UWB), and band-notched UWB using a miniaturized novel resonator. Three essential responses can be achieved from the same resonator by adequately utilizing the two capacitors. The first essential narrowband behavior is obtained from the resonator at 0.1pF is WLAN (5.5 GHz) operating frequency band. The second wideband behavior is achieved from the resonator to work between 3-11 GHz UWB frequency band. This behavior is achieved by changing the value of capacitors from 0.1 pF to 0.8pF. Finally, band-notched UWB response has been achieved by adjusting the position of capacitors, and this bandnotch behavior can also be tuned continuously between WLAN and WiMAX frequency band. The antenna designed for these objectives have a compact size of 24×30.5 mm2 including the particular ground plane. The clean and consistent radiation pattern of the antenna is observed because of the placement of the resonators in the partial ground plane. The antenna is also fabricated, and its response to three behaviors is measured for validation.
Author(s): M. NejatiJahromi, M. NagshvarianJahromi, M. Rahman
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: High-Resolution Ultra-Wideband Material Penetrating Radar (UWB-MPR) using Modified Configuration of Receiver Antennas
Abstract: In this paper, in order to implement the see through the wall and ground penetrating radars using vector network analyzer at the first step we present a modified UWB Tapered Slot Antenna (TSA) and Wilkinson power combiner. In the following the main purpose of this paper is employing a new technique using modified UWB antennas and power combiner to improve the reflected signal of localizing underground metal for 1D visualization of material penetrating radar results. In the last section two scenarios of GPR profiles with a single receiver antenna and dual receiver antennas over ground surface with buried metal target are presented to validate the accuracy of the proposed approach. This signal collecting technique collect more energy form reflected signals in contrast with conventional MPR. Hence, stronger reflection is available to achieve higher chance for target localization.
Author(s): M. Ojaroudi, H. Jahed
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Dual Layer Convoluted Frequency Selective Surface Design in the 2.4 GHz and 5.8 GHz ISM Bands
Abstract: Indoor wireless devices operating in 2.4 GHz and 5.8 GHz ISM bands have a wide range of usage area. However, mutual interference in neighboring networks degrades the system performance. It can also cause significant problems in secure personal communications on such wireless networks. Covering building walls with a band stop frequency selective surface (FSS) can be an efficient solution for such problems. Many available FSS structures are designed to have a single stop band. They are also subject to narrow incidence angle range and sensitive to the polarization of the wave. On the other hand, in some studies, FSSs with double stop band are designed such that the second stop band is to be the harmonic frequency of the first band. In this study, a dual layer frequency selective surface element geometry is introduced. This geometry is capable of at least 20 dB attenuation of incoming signals within the incident angle range from 0 to 60 degrees and for all polarizations. Another important contribution is that a periodic cell size of approximately one-tenth of the wavelength corresponding to 2.4 GHz is obtained. Besides, a new design methodology that enables almost independent optimization of each layer at its resonance frequency is also introduced.
Author(s): B. Doken, M. Kartal
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
Download Link:Click here to download PDF     File Size: 2122 KB

Title: Near to Far-Field Plane-Polar Transformation from Probe Positioning Error Affected Data
Abstract: In this article, two efficient approaches for the correction of known positioning errors of the measurement probe in a plane-polar near to far-field (NTFF) transformation, requiring a minimum number of NF data in the case of quasi-planar antennas, are presented and experimentally assessed. Such a NTFF transformation benefits from a non-redundant sampling representation of the voltage detected by the probe got by modeling an antenna with a quasi-planar geometry through a double bowl, a surface consisting of two circular bowls with the same aperture radius, but with lateral bends which may differ to better fit the antenna shape. The uniform samples, i.e., those at the points set by the representation, are accurately retrieved from the collected not regularly distributed ones either by applying a singular value decomposition based approach or an iterative scheme. Then, the input NF data necessary for the classical plane-rectangular NTFF transformation are evaluated from the so retrieved non-redundant uniform samples through a 2-D optimal sampling interpolation formula.
Author(s): F. D’Agostino, F. Ferrara, C. Gennarelli, R. Guerriero, M. Migliozzi
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
Download Link:Click here to download PDF     File Size: 3201 KB

Title: High-order Staggered Finite Difference Time Domain Method for Dispersive Debye Medium
Abstract: In this paper, a high order accuracy Finite Difference Time Domain method was proposed for the simulation of electromagnetic waves in the Debye dispersive medium. The proposed method was based on the use of the third order Backward Differentiation scheme for the approximation of the time derivatives and the use of the fourth order Central Finite Difference scheme for the approximation of space derivatives. The stability of the present method was analyzed by using the Root-Locus method. The accuracy of the proposed method was analyzed in the case of free space and the dispersive media, in the case of plane wave and the case of a Hertzian dipole source. The proposed method offered high performance regarding the accuracy and the stability in comparison with the other methods.
Author(s): A. Guellab, W. Qun
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Effective CFS-PML Formulations Based on 2-D TE phi BOR-FDTD for the Drude Model
Abstract: Effective formulations of the complex frequency-shifted perfectly matched layer (CFS-PML) based on the two-dimensional (2-D) TE phi body of revolution finite-difference time-domain (BOR-FDTD), named as the BOR-CFS-PML, are proposed to truncate the Drude media. The auxiliary differential equation (ADE) method and the trapezoidal recursive convolution (TRC) method are applied to the implementation of the BOR-CFS-PML. The proposed formulations have good performance in attenuating low-frequency evanescent waves and reducing late-time reflections. A numerical test is provided to validate the effectiveness of the proposed algorithm.
Author(s): J. Li, W. Jiao
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Complex-Envelope ADE-LOD-FDTD for Band Gap Analysis of Plasma Photonic Crystals
Abstract: In this paper, a complex-envelope (CE) scheme is introduced into the locally one-dimensional finite-difference time-domain (LOD-FDTD) method for the band-gap analysis of the plasma photonic crystal (PPC). The un-magnetized plasma, characterized by a complex frequency-dependent permittivity, is expressed by the Drude model and solved with a generalized auxiliary differential equation (ADE) technique. The CE scheme is also applied to the perfectly matched layer. Numerical examples show that the proposed CE-ADELOD- FDTD method provides much more accurate results than the traditional ADE-LOD-FDTD with the same CFL number. The reflection and transmission coefficients of the PPC are calculated and their dependence on the relative permittivity of dielectric, the plasma frequency, the collision frequency and the plasma layer thickness is studied. The results show that the photonic band gaps of the PPC could be tuned by adjusting the parameters.
Author(s): T.-L. Liang, W. Shao, S.-B. Shi
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: FPGA Based Fast Bartlett DoA Estimator for ULA Antenna Using Parallel Computing
Abstract: This paper presents a design and implementation of a structure which uses Bartlett Direction of Arrival (DoA) algorithm and a receiver system on Altera Cyclone IV and Cyclone III FPGAs. First of all, a software defined radio (SDR) that has 4 simultaneous inputs, is designed. All data used in this study are obtained by using this radio system. Then one of the FPGA is configured as antenna simulator and the other one is used for implementing Bartlett DoA estimation algorithm. Bartlett DoA estimation algorithm is developed completely in parallel and compared with a previous study which is performed sequentially on an FPGA using NIOS processor. The designs are tested by using 4-element Uniform Linear Array (ULA) antenna. Implemented hardware is compared in terms of DoA calculation speed and the sources that occupy on the FPGA. Furthermore, the paper has significant improvement in calculation duration thereby achieving lower response latency compared with previously published similar works.
Author(s): F. M. Unlersen, E. Yaldiz, S. T. Imeci
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
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Title: Experimental Characterization of an All-Dielectric Metasurface with Optical Activity Properties
Abstract: A new microwave all-dielectric metasurface based on elliptic dielectric resonators (EDRs) with optical activity properties was fabricated and characterized experimentally. The 5.12 mm-thick metasurface is composed of two layers of connected elliptic dielectric resonators (Rogers RO3210) with elliptic slots and was excited with two orthogonal polarizations of the incident electric field. The optical activity was studied through two constitutive parameters representing the rotation angle theta and polarization state (eta) of incident and transmitted electric fields through the metasurface. It is found that the proposed design may rotate the incident linearly polarized electric fields over many frequency bands with different transmissions levels. The obtained performances may offer to the device the possibility to be used as microwave polarization rotator.
Author(s): A. Yahyaoui, H. Rmili
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
Download Link:Click here to download PDF     File Size: 1741 KB

Title: A Direct Solver Based on Rank-Structured Matrix for Large Arrays in Method of Moment
Abstract: Rank-structured matrices such as H-matrix, H2-matrix and hierarchically semi-separable (HSS) have be applied to solve integral equation problems in some engineering applications. In Method of Moment (MoM), the discretization of electric field integral equation (EFIE) usually leads to a dense matrix. However, by considering the low-rank properties of off-diagonal blocks, the rank-structured theory provides a novel sparse representation for the resulting matrix. In this paper, we propose a direct solver based on one-level rank-structured matrix to analysis the electromagnetic characteristics of large arrays. The memory requirements are compared to those of direct solver and advantages of the proposed method are validated by numerical examples.
Author(s): W. Yu, H. Yang, S. Li, Y. Xu
File Type: Journal Paper
Issue:Volume: 33      Number: 4      Year: 2018
Download Link:Click here to download PDF     File Size: 1656 KB