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Title: ACES Journal March 2016 Cover
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: ACES Journal March 2016 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: ACES Journal March 2016 Full
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Discretized Aperture Integration, Surface Integration Analysis of Airborne Radomes
Abstract: Full-wave electromagnetic methods are becoming increasingly more viable for the design and analysis of airborne radomes; however, there still exist many applications that require the speed associated with high frequency approximation methods. Presented here are accuracy improvements to the aperture integration surface integration (AiSi) method by incorporating both aperture and radome discretization into smaller groups in advance of the propagation routines, herein referred to as discretized radome discretized aperture integration surface integration (DrDaiSi). Dyadic Greenís functions are utilized to determine exact field vectors from source current vectors. The capabilities of DrDaiSi are welltested for typical airborne radomes, and a case study is presented which includes a 2:1 fineness ratio tangent ogive radome with dielectric constant of 7 and a metallic tip. The benefits of the DrDaiSi algorithm over a nondiscretized AiSi method for predicting radome loss, boresight error, and radiation pattern degradation are demonstrated. Results are compared to a full-wave solution of the antenna and radome problem that was solved in CST to represent ďtruth.Ē Transmission loss agreement is achieved to within 0.4 dB or better, and boresight error agreement is achieved to within 0.2 deg. or better in both elevation and azimuth scan planes for a severely detuned radome.
Author(s): J. W. Jordan, B. L. Cannon
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Indoor Wave Propagation Prediction for Corridors Segments with Partially Reflecting Walls by Using 3D Waveguide Modal Analysis
Abstract: In this paper, a model is presented to simulate wave propagation in indoor corridors with partially reflecting walls. The model is based on combination of modal analysis, dyadic Greenís function, mode matching method and generalized scattering matrix. A new approach to simulate the effect of partial reflectivity of the walls of the waveguide model is proposed. This approach is based on approximating the fields inside the space of the actual waveguide section by equivalent waveguide sections of larger dimensions with PEC (Perfect Electric Conductor) walls. A simple scenario is considered in order to check the accuracy of this model. This scenario is verified by comparing experimental and numerical simulation results. The obtained results show that the proposed model is suitable for predicting accurate electric field strength due to an electromagnetic source in an indoor environment with partially reflecting boundaries.
Author(s): H. M. El-Maghrabi, A. M. Attiya, E. A. Hashish
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Analysis and Simulation of Energy Leakage for the Surface-Wave Waveguide Based on Tunable Impedance Cells
Abstract: Controlling energy leakage is of great importance for users of surface-wave waveguides (SWGs) because it determines the propagating efficiency of surface waves. In this paper, a novel theoretical analysis of the energy leakage for these two types of SWGs is proposed, and the effects of some key parameters to the leakage such as the path width of the SWG and effective impedance of cell and incident angle are discussed more deeply. To verify the theoretical method, a model of the SWG consisting of 30 ◊ 30 impedance-tunable cells driven by TM surface waves, whose impedance ranges from j370 ? to j780 ? according to our previous measurements, is simulated in HFSS. The simulation results are in good agreement with the theoretical ones, demonstrating that the leakage is inversely proportional to the width of the SWG and an increase of effective impedance of the guided path; furthermore, by using the impedance-tunable cells, the multi-functionality of the SWG is illustrated. The analyzing methods can be a guide for designing other SWGs without energy leakage, and as an inspiration for more complex SWG applications.
Author(s): Y. Zhou, X. Chen, Z. Luo
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Short Pulse Propagation along Microstrip Meander Delay Lines with Design Constraints: Comparative Analysis of the Quasi-static and Electromagnetic Approaches
Abstract: Short pulse propagation along microstrip meander delay lines is considered. Electromagnetic analysis is used in the CST MWS software. A quasistatic analysis in TALGAT software is used as another approach, for which the complete computational models for capacitive matrix calculation are presented. The results of simulations are given. It is shown that if a number of turns is increased and their length is reduced proportionally, distortions of a pulse signal in the line are reduced. At the same time, though the electrical width of the structure increases, an agreement between the results of quasi-static and electromagnetic analyses is improved. Memory costs of electromagnetic analysis and quasi-static analysis are comparable, while the latter is significantly less time-consuming. Thus, it is demonstrated that a quasi-static analysis can be quite relevant during the design of the microstrip meander delay lines with minimal distortions.
Author(s): P. Orlov, T. Gazizov, A. Zabolotsky
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Broad-Band and Wide Scan Phased Array Element Design Using Data Mining
Abstract: Novel synthesis procedure, exploiting data mining technique for antenna design is presented. By utilizing data mining, investigating various combinations of a typical antenna configuration, all together, is feasible and this fact allows the selection of the specific design which possesses the desired properties. In this paper, a broad-band and wide scanning angle probe-fed microstrip patch array element with shorting posts is designed based on this procedure. For achieving acceptable bandwidth, scan angle and polarization, the coordination positions and the number of the incorporated shorting posts were considered as the design parameters. For a substrate with a thickness of 0.05?0, the simulation results show a 15% frequency bandwidth with a scanning range of 70? in the main E, H and D-planes.
Author(s): G. Dadashzadeh, M. Kargar, Y. Torabi, B. Rahmati
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: A Compact MIMO Ultra-Wide Band Antenna with Low Mutual Coupling
Abstract: In this paper, a novel compact multipleinput multiple-output (MIMO) antenna with the size of 26 mm ◊ 60 mm ◊ 1.6 mm for ultra-wide band (UWB) applications is proposed. The proposed MIMO antenna consists of two single UWB antennas and a stub placed between the two antennas to reduce the mutual coupling. The proposed antenna achieves the voltage standing wave ratio (VSWR) less than 2 and more than 86% radiation efficiency over the whole band of interest. Performance of the antenna is examined using both simulation and experiment.
Author(s): Q. D. Nguyen, T. T. Le, D. T. Le, X. N. Tran, Y. Yamada
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: The Sinusoidal Ground Electrode: Theory and Case Study Results
Abstract: This paper presents the analytical analysis of the sinusoidal ground electrode commonly used in Portugal by the Portuguese Electric Company. This electrode is easy to install, particularly for two layer soils with rocky bottom layer, and costs much less than it does a strip conductor. Both the theoretical results as well as measurements in the field have shown that the empirical model used by the company leads to large errors. Here the authors propose a new procedure to calculate the grounding resistance for this type of electrode using the average resistance between the wire and strip electrodes, which the calculation is well-established. To avoid heavy computation, the authors also propose the use of simple formulas in order to easily compute the strip resistance. The theoretical results and field measurements are compared and show the validity of the procedure being proposed here.
Author(s): A. M. R. Martins, S. J. P. S. Mariano, M. R. A. Calado, J. A. M. Felippe de Souza
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Effects of Coil Locations on Wireless Power Transfer via Magnetic Resonance Coupling
Abstract: The coil locations have strong impacts on efficiency, resonant frequency and bandwidth in the wireless power transfer (WPT) system with four coil resonators, which is a popular configuration for midrange WPT via magnetic resonance coupling. Herein, effects of coil location parameters, such as the distances between neighboring coils, are investigated by virtue of full-wave electromagnetic solution and validated by measurements. Three operational regions can be defined in terms of the distances between neighboring coils: over coupling, strong coupling and under coupling. It is shown that the distance between the receiving coil and the load coil has significant impact on the power transfer efficiency whereas the distance between the driving coil and the transmitting coil may merely affect the bandwidth and the resonant frequency in the strong coupling regime. In addition, the distance between the transmitting coil and the receiving coil can have strong impact on both the bandwidth and the resonant frequency. Design guidelines for optimal coil locations, by which the highest transfer efficiency or the longest transfer distance can be achieved, are also discussed.
Author(s): X. Shi, C. Qi, M. Qu, S. Ye, G. Wang
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
Download Link:Click here to download PDF     File Size: 493 KB

Title: Stochastic Radiation Model for Cable Bundle with Random Wires
Abstract: Cable bundle is often the main radiation structure due to its length in automotive electrical or electronic systems. Random wire positions in a cable bundle is a challenge for the modeling in perspective of Electromagnetic Compatibility (EMC). This work addresses the uncertainty property of a cable bundle due to its random wire positions, through a stochastic-model approach. Random wire position distributions in a bundle adopt Gaussian norm. A spline interpolate function is used to improve the continuity of wires along the bundle. To calculate the common-mode (CM) current on the bundle, the composed non-uniform wires are modeled by cascaded uniform segments or Chebyshev Expansion Method based smooth lines. Further CM current based bundle radiation is calculated using electric-dipole model. Proposed modeling methodology is assessed by comparing CM current and radiation predictions versus measurement data and theoretical results. Predictions agree well with measurements especially in statistics.
Author(s): J. Jia, Z. Lai, J. Lei, Q. Wang
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Compact and Planar WCDMA/WLAN/UWB Antenna with Shorted Loop and Monopole Elements
Abstract: A compact, planar, multiband antenna with loop and monopole elements suitable for wideband code division multiple access (WCDMA), wireless LAN (WLAN), and ultra wideband (UWB) wireless communications is presented in this paper. The antenna was built on FR4-type substrate and fed by a microstrip transmission line for easy integration with RF/microwave circuitry on the same circuit board. The physical lowband of the antenna includes 1.9?2.17-GHz WCDMA and 2.45-GHz WLAN bands, whereas the high-band spans from about 3.3 to about 11-GHz including 5-GHz WLAN, 3.1?10.6-GHz UWB, and 4?8-GHz C bands. Antenna S11 and radiation pattern measurements are presented. Itís shown that measurements and simulations are in good agreement.
Author(s): B. S. Yildirim, E. Basaran, B. Turetken
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Magnet Modification to Reduce Pulsating Torque for Axial Flux Permanent Magnet Synchronous Machines
Abstract: To reduce pulsating torque without sacrificing the average torque significantly in axial flux permanent magnet synchronous machines (AFPMSM), this paper presents two optimization techniques which are based on magnet modification: i) combine magnet circumferential displacement with various pole-arc ratios (method one); ii) magnet axial shape design (method two). Firstly, analytical models of air gap magnetic field were derived for the above two methods. Then, according to Maxwell stress tensor method, the analytical expressions of cogging torque and electromagnetic torque were obtained. Average torque, cogging torque and electromagnetic torque ripple were considered simultaneously in the optimization using multi-objective genetic algorithm (MOGA) with the help of the analytical torque models. Finally, 3D finite element models were established to verify the two torque optimization methods. The proposed methods were also compared with skew technique, which is widely used nowadays. Result showed that the proposed optimization techniques can greatly reduce the overall pulsating torque without decreasing the average torque and did not increase the use of permanent magnet.
Author(s): S. Wu, S. Zuo, X. Wu, F. Lin, J. Shen
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Miniaturization of a Broadband Quadrature Hybrid Coupler Using ?-Model Transformation-Based Artificial Transmission Line
Abstract: In this paper, a novel compact broadband quadrature hybrid coupler based on planar artificial transmission line is presented. This coupler can be used for WLAN application at 2.4 GHz. The planar artificial transmission line has been implemented using ?-model technique. The size of the proposed coupler is merely 38% of that of a conventional one. The compact coupler performs well wideband response.
Author(s): V. I. Nejad, A. A. Lotfi-Neyestanak, A. Shahzadi
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
Download Link:Click here to download PDF     File Size: 500 KB

Title: Development of a Symmetric Waveguide T-Junction Power Divider with Equal-Phase Characteristic
Abstract: An efficient method is proposed to design a versatile rectangular waveguide T-junction power divider without changing the length of either of the output branches for phase compensation. Instead, the phase balance is controlled by the widths of the output branches, which, in turn, help to achieve the same timeof- arrival of waves propagating to the two output ports. This method does not sacrifice the T-junctionís symmetric characteristic physically. Numerical analysis has been utilized to design several T-junction power dividers operating in Ku-Band with different power ratios, and results are compared with the measured ones to verify the design feasibility.
Author(s): G.-L. Huang, S.-G. Zhou, T.-H. Chio
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
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Title: Near-Field Focused Folded Transmitarray Antenna for Medical Applications
Abstract: A near-field focused folded transmitarray antenna is proposed at 2.45 GHz for medical applications. The proposed folded transmitarray construction introduces compact design, low profile, and reduced fabrication cost with focused power in both the near-field and far-field regions of the antenna. The transmitarray consists of a feeding horn antenna embedded centrally in the transmitarray structure and a perfect electric conductor plate with the same size as a reflector. The radiation from the feeding horn is reflected by the plate toward the transmitarray. The unit-cell element of the transmitarray is a square dielectric box with four identical circular holes. The transmission coefficient was nearly -3 dB in magnitude and 320 degrees in phase. The radiation characteristics of the unfolded and folded transmitarray are analyzed using the finite integral technique. The normalized power density distribution around a part of the human leg placed in front of the transmitarray is investigated. The proposed antenna is used to heat a specific area on the human leg for treatment.
Author(s): S. H. Zainud-Deen, W. M. Hassan, H. A. Malhat
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
Download Link:Click here to download PDF     File Size: 980 KB

Title: A Compact Dual-Band Patch Antenna Design Based on Single-Ring Split Ring Resonator
Abstract: A compact dual-band patch antenna based on split ring resonator (SRR) element is demonstrated in this paper. In the design, a single-ring SRR, acting as a near-field resonant parasitic (NFRP) element, is integrated in the same plane of radiating patch. The addition of SRR could create a new operational frequency band much lower than the patch fundamental mode, lower the patch resonance frequency, and improve the patch impedance bandwidth significantly, while maintaining the antenna simplicity and compactness. The experimental results are in agreement with the simulation values, demonstrating that our proposed antenna possesses an excellent dual-band radiation performance characteristic, which includes relatively high radiation efficiencies, low crosspolarization levels, and stable broadside radiation performances.
Author(s): M.-C. Tang, H. Wang, L. Guo, X. Zeng, H. Liu, Y. Pang
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
Download Link:Click here to download PDF     File Size: 841 KB

Title: Microstrip Fed Multiband Hybrid Fractal Antenna for Wireless Applications
Abstract: A hybrid fractal multiband antenna is designed by integrating Koch curve and meander antenna. Scripting method (*.vbs) is adopted to obtain the hybrid fractal structure using IFS and MATLAB. Final structure is obtained by perturbing the reference fractal shape. Proposed antenna exhibits multiband characteristics capable of operating in four different wireless frequency bands including very popular Bluetooth (2.4 GHz), WiMAX (3.4-3.7 GHz), WLAN 802.11 a/b/g (5.3-6.1 GHz) and Aeronautical radionavigation (8.68-9.05GHz). The antenna has a planar structure, compact size of 39 mm ◊ 32 mm ◊ 1.58 mm and is suitable for wireless applications. Prototype of the proposed structure is developed on easily available and low cost FR4 substrate. The antenna has acceptable values of return loss, VSWR and gain. Measured characteristics are in good agreement with the simulated one.
Author(s): Y. Kumar, S. Singh
File Type: Journal Paper
Issue:Volume: 31      Number: 3      Year: 2016
Download Link:Click here to download PDF     File Size: 604 KB