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Title: ACES Journal August 2023 Cover
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
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Title: ACES Journal August 2023 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 179 KB

Title: ACES Journal August 2023 Full
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 12314 KB

Title: An Implicit Adaptive FDTD Mesh Generation Technique based on Tetrahedrons
Abstract: A novel implicit adaptive FDTD mesh generation method based on tetrahedrons is proposed in this paper. According to the vertex coordinates of tetrahedrons which make up an object, non-uniform grid lines are generated first. These grid lines are constrained by the structure of the object and follow three rules mentioned in the paper. The first rule is to find demarcation points of the object and drop grid lines on these points. The second rule is to make sure all mesh sizes are less than one-tenth of the wavelength by adding more grid lines. The last rule is to densify mesh at the fine structure of the object. Then by comparing the positional relationship between center points of Yee cells and tetrahedrons, the object can be discretized by Yee cells. Finally, numerical examples are given to verify the validity and accuracy of this novel method.
Author(s): W. Zhang, Z. Xu, H. Peng, J. Chen, C. Mou
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 2489 KB

Title: A Novel 3-D DGTD-FDTD Hybrid Method with One Overlapping Virtual Layer
Abstract: Compared with the traditional finite difference time-domain (FDTD) method, the discontinuous Galerkin time-domain (DGTD) method may face the issue of intense computation. In this paper, a novel 3-D DGTD-FDTD hybrid method is proposed to dramatically reduce the unknowns of the DGTD method. Instead of the common mass-lumped elements, this virtual layer of the Yee grid is implemented on the intersecting boundary, which simplifies the mesh generation and reduces the number of unknowns. To validate the proposed method, two examples of sphere scattering and horn antenna are considered. The simulation results demonstrate the effectiveness of the proposed method.
Author(s): Q. Wu, K. Wang, Z. Lin, Y. Zhang, X. Zhao
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 3902 KB

Title: Research on a Two-stage Plane Adaptive Sampling Algorithm for Near-field Scanning Acceleration
Abstract: As one of the most useful methods in electromagnetic interference (EMI) diagnosis, near-field (NF) scanning is widely used in electromagnetic compatibility (EMC) evaluation of complex devices under test (DUTs). In this paper, a two-stage plane adaptive sampling algorithm is proposed to reduce the acquisition time in the process of NF scanning and to make reconstruction of the radiation source more efficient. The sampling method is based on the region self-growth algorithm and the Voronoi subdivision principle, significantly reducing the number of NF samples in the stage of solving the radiation source model through uniform and non-uniform two-stage sampling. Two experiments were conducted to verify the correctness and effectiveness by comparing with the traditional uniform sampling method.
Author(s): X. Liu, P. Zhang, D. Shi
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 4725 KB

Title: Fast Coupling Iterative Algorithm for Media Rough Surface with Multiple Targets Below
Abstract: This paper proposes a fast mutual coupling iteration algorithm for analyzing the composite electromagnetic scattering characteristics of a Gaussian rough surface with multiple targets below it. Firstly, an electromagnetic scattering model of Gaussian rough surface with multiple targets underneath is established. To improve the efficiency of electromagnetic scattering calculations, the (banded matrix iterative approach canonical grid - conjugate gradient method (BMIA/CAG-CMG) algorithm is used to calculate the surface scattering of the rough surface, while for the scattering of the targets, the traditional numerical algorithm moment of methods (MoM) is used for the calculation. Its main acceleration principle is to decompose the matrix into banded and Toeplitz matrices during the solution process, and then use fast Fourier transform (FFT) for fast solution based on their characteristics. By comparing the calculation results of this algorithm with those of the MoM algorithm, the correctness of this algorithm is verified. Several examples are studied, and the impact of different parameters on the surface current and composite scattering characteristics is discussed, which have important significance for deepening the understanding of scattering characteristics in complex electromagnetic environments.
Author(s): L. Lei
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 7411 KB

Title: fficient Improved Local Time Stepping with the Leapfrog Scheme for Transient 3-D Electromagnetic Analyses
Abstract: An alternate boundary local time stepping (ABLTS) method is proposed for the discontinuous Galerkin time domain method for transient electromagnetic simulations to reduce the computation complexity of the local time stepping (LTS) method. The proposed method exhibites lower storage and time complexity than the conventional LF-LTS method . The stability, accuracy, and effectiveness of the ABLTS method are verified by applying it to the simulation of a resonator cavity and multi-layer microstrip antenna. The numerical results revealed that the developed method is effective for the transient electromagnetic simulation of antennas.
Author(s): M. Li, Q. Wu, Z. Lin, Y. Zhang, X. Zhao
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 8687 KB

Title: Novel Characteristic Mode Basis Functions Accelerating Iteration Convergence of CMM for Analyzing Electromagnetic Scattering Problems
Abstract: In this study, a novel characteristic mode basis function construction method is proposed to solve the problems of low efficiency and slow convergence of the iterative solution of the characteristic mode method. First, the characteristic modes (CMs) of each extended block are calculated separately by dividing objects, the CMs construction efficiency is improved for the decreased matrix dimensionality. Next, the effective CMs are selected as basis functions according to the modal significances. Finally, to improve the poor conditional number of the reduced matrix for the block extension, the singular value decomposition is used to enhance the orthogonality among these basis functions. Several numerical calculations show that the proposed method has significant efficiency and accuracy.
Author(s): F. Guo, Z. Wang, Y. Sun, W. Nie, P. Wang, J. Wu
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 1436 KB

Title: Gain-enhanced and Mechanical Reconfigurable Slot Antenna with Metasurface
Abstract: A novel wideband slot antenna with metasurface is presented. In order to achieve broadband, high-gain, and mechanical reconfigurable performance, a metasurface is adopted and combined with a new-type planar slot antenna The antenna and metasurface are designed on F4B substrate, and the overall dimension of the antenna is 1.48λ0×1.48λ0×0.2λ0 (λ0 is the free space wavelength at center frequency). Different from the traditional square metasurface, a structure with different properties in the x and y directions is utilized in the proposed antenna, which can be reconstructed by adjusting the relative position between the slot antenna and the metasurface. By introducing the metasurface, the maximum gain of the whole antenna is improved. The antenna works in two states with respect to the two locations of the metasurface. The impedance bandwidth of the proposed antenna in state A is from 5.49 to 9.40 GHz (52.5%), and the impedance bandwidth of the proposed antenna in state B is from 5.83 to 6.01 GHz (3%) and 7.05 to 9.62 GHz (30.8%). The gain of the whole antenna in both states is higher than that of the original slot antenna (without metasurface), and the maximum gain is 9.1 dBi.
Author(s): X. Song, A. Dong, X. Li, Y. Zhang, H. Lin, Y. Li, H. Yang
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 8682 KB

Title: Wideband Monostatic RCS Prediction of Complex Objects using Support Vector Regression and Grey-wolf Optimizer
Abstract: This paper presents a method based on the support vector regression (SVR) model and grey wolf optimizer (GWO) algorithm to efficiently predict the monostatic radar cross-section (mono-RCS) of complex objects over a wide angular range and frequency band. Using only a small-size of the mono-RCS data as the training set to construct the SVR model, the proposed method can predict accurate mono-RCS of complex objects under arbitrary incident angle over the entire three-dimensional space. In addition, the wideband prediction capability of the method is significantly enhanced by incorporating the meta-heuristic algorithm GWO. Numerical experiments verify the efficiency and accuracy of the proposed SVR-GWO model over a wide frequency band.
Author(s): Z. Zhang, P. Wang, M. He
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 13038 KB

Title: High-precision Solution of Monostatic Radar Cross Section based on Compressive Sensing and QR Decomposition Techniques
Abstract: In solving the monostatic electromagnetic scattering problem, the traditional improved primary characteristic basis function method (IPCBFM) often encounters difficulties in constructing the reduced matrix due to the long computation time and low accuracy. Therefore, a new method combining the compressed sensing (CS) technique with IPCBFM is proposed and applied to solve the monostatic electromagnetic scattering problem. The proposed method utilizes the characteristic basis functions (CBFs) generated by the IPCBFM to achieve a sparse transformation of the surface-induced currents. Several rows in the impedance matrix and excitation vector are selected as the observation matrix and observation vector. The QR decomposition is adopted as the recovery algorithm to realize the recovery of surfaceinduced currents. Numerical simulations are performed for cylinder, cube, and almond models, and the results show that the new method has higher solution accuracy, shorter computation time, and stronger solution stability than the traditional IPCBFM. It is worth mentioning that the new method reduces the recovery matrix size and the number of CBFs quantitatively, and provides a novel solution for solving monostatic RCS of complex targets.
Author(s): C. Shi, Y. Sun, M. Ou, P. Wang, Z. Wang
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 3675 KB

Title: Analytical Solution of Eddy Current in Parallel Conducting Strips for Low-frequency Shielding Purposes
Abstract: In instrumentation systems, shielding is the main issue that judges the performance of the system. The electromagnetic (EM) noise may affect the performance of the instrumentation system if inadequate protection is reached. It is considered the main source of unprotectable interference that may affect these systems in many cases. In this paper, shielding is attained by wrapping the source carrying signal with periodic thin conductive strips separated by slots or openings. This arrangement will protect the sources from the outside EM fields. Shielding factor and shielding efficiency are studied by extracting magnetic fields. For this purpose, an analytical solution based on solving Laplace’s equation for the magnetic vector potential in the region of interest is presented. A closed form of the induced eddy current in the conductive strips is calculated based on Fourier series expansion. Furthermore, numerical simulation using the commercial software MWS CST is employed to validate the analytical solution. The performance of the proposed shielding structure is studied and analyzed in terms of shielding factor and shielding efficiency. The outcomes of both methods are showing very good agreement.
Author(s): H. M. Jaradat, Q. M. Qananwah, A. M. Dagamseh, Q. M. Al-Zoubi
File Type: Journal Paper
Issue:Volume: 38      Number: 8      Year: 2023
Download Link:Click here to download PDF     File Size: 1957 KB