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IEEE Electrical Design of Advanced Packaging

作者： Tsiklauri, Mikheil Zvonkin, Mikhail Dikhaminjia, Nana Fan, Jun Drewniak, James Missouri Univ Sci & Technol EMC Lab Rolla MO 65401 USA

ISBN: (纸本)9781467380997

Checking and enforcing causality of simulated or measured system data is a crucial step for obtaining valid results. Previously, several methods for both frequency and time domain have been proposed. This paper explores the time domain causality enforcement method, its effect on the frequency domain transfer function, and proposes modification of the recursive convolution algorithm for impulse responses with time domain enforced causality to ensure calculation stability.

关键词： Impulse response Transient simulations Causality checking Causality enforcement recursive convolution

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A Novel Piecewise Linear recursive convolution Approach for Dispersive Media Using the Finite-Difference Time-Domain Method

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 2014年第5期62卷 2669-2678页

作者： Giannakis, Iraklis Giannopoulos, Antonios Univ Edinburgh Inst Infrastruct & Environm Sch Engn Edinburgh EH9 3JL Midlothian Scotland

Two novel methods for implementing recursively the convolution between the electric field and a time dependent electric susceptibility function in the finite-difference time domain (FDTD) method are presented. Both resulting algorithms are straightforward to implement and employ an inclusive susceptibility function which holds as special cases the Lorentz, Debye, and Drude media relaxations. The accuracy of the new proposed algorithms is found to be systematically improved when compared to existing standard piecewise linear recursive convolution (PLRC) approaches, it is conjectured that the reason for this improvement is that the new proposed algorithms do not make any assumptions about the time variation of the polarization density in each time interval;no finite difference or semi-implicit schemes are used for the calculation of the polarization density. The only assumption that these two new methods make is that the first time derivative of the electric field is constant within each FDTD time interval.

关键词： Complex-conjugate pole-residue pairs Debye Drude finite-difference time domain (FDTD) linear dispersive materials Lorentz PLRC recursive convolution TRC

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A Vectorial Discontinuous Galerkin Time-Domain Method Incorporating Generalized Sheet Transition Conditions

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2022年第8期70卷 3765-3775页

作者： Wu, Kaiming Tian, Shaowen Ren, Qiang Beihang Univ Sch Elect & Informat Engn Beijing Peoples R China

A vectorial discontinuous Galerkin time-domain method incorporating generalized sheet transition conditions (DGTD-GSTC) is proposed for the simulation of curve metasurfaces. This scheme utilizes virtual fields to realize the discontinuity across the metasurface described by GSTCs, which is beyond the ability of conventional boundary conditions. Compared to the previous research on modeling approaches for metasurfaces based on GSTCs, this scheme is particularly suited for solving practical metasurface problems due to its ability for complex geometry modeling and broadband analysis. This scheme is also shown to provide a fundamental generalization of the conventional DGTD technique. Five 2-D representative examples are presented to validate the effectiveness of this newly proposed method.

关键词： Metasurfaces Time-domain analysis Method of moments Mathematical models Fourier transforms Frequency-domain analysis Tensors Curved metasurfaces discontinuous Galerkin time-domain (DGTD) method generalized sheet transition conditions (GSTCs) recursive convolution virtual fields

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Real-Time Image Super-Resolution Using recursive Depthwise Separable convolution Network

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IEEE ACCESS 2019年 7卷 99804-99816页

作者： Hung, Kwok-Wai Zhang, Zhikai Jiang, Jianmin Shenzhen Univ Coll Comp Sci & Software Engn Shenzhen 518000 Peoples R China

In recent years, deep convolutional neural networks (CNNs) have been widely used for image super-resolution (SR) to achieve a range of sophisticated performances. Despite the significant advancement made in CNNs, it is still difficult to apply CNNs to practical SR applications due to enormous computations of deep convolutions. In this paper, we propose two lightweight deep neural networks using depthwise separable convolution for the real-time image SR. Specifically, depthwise separable convolution divides the standard convolution into depthwise convolution and pointwise convolution to significantly reduce the number of model parameters and multiplication operations. Moreover, recursive learning is adopted to increase the depth and receptive field of the network in order to improve the SR quality without increasing the model parameters. Finally, we propose a novel technique called Super-Sampling (SS) to learn more abundant high-resolution information by over-sampling the output image followed by adaptive down-sampling. The proposed two models, named SSNet-M and SSNet, outperform the existing state-of-the-art real-time image SR networks, including SRCNN, FSRCNN, ESPCN, and VDSR, in terms of model complexity, and subjective and PSNR/SSIM evaluations on Set5, Set14, B100, Urban100, and Manga109.

关键词： Super-resolution depthwise separable convolution super-sampling recursive convolution

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Research on application of ground penetrating radar array method based on plane beam signal in different geological models

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ACTA GEOPHYSICA 2021年第6期69卷 2241-2260页

作者： Cui, Fan Chen, Yi Zhang, Yongqi Du, Yunfei China Univ Min & Technol Beijing Sch Geosci & Surveying Engn Beijing Peoples R China China Univ Min & Technol Beijing State Key Lab Coal Resources & Safe Min Beijing Peoples R China Beijing Key Lab Precise Min Intergrown Energy & R Beijing Peoples R China

The traditional common-offset ground penetrating radar method measures point by point along the survey line with a single transmitter and a single receiver. Due to the influence of the antenna radiation power and the low-pass filtering function of the earth medium, an intense amplitude gain cannot be obtained when the signal is intercepted. This article addresses a plane beam signal ground penetrating radar array observation method based on high radiation power gain. The transmitting antenna array simultaneously excites the pulse signal with the same centre frequency. All the transmitted signals interfere with each other at the near surface to form a plane beam signal, and the electromagnetic energy is superimposed mutually to increase the radiation power. We applied the plane beam signal ground penetrating radar array method to different geological models constructed by the finite difference time-domain (FDTD) algorithm for numerical simulation in this research. Since there are various offsets in the array ground penetrating radar observation method, we introduce a composite frequency shift-perfect matching layer (CFS-PML) based on the recursive convolution method as the absorbing boundary condition. It eliminates the problem of secondary reflection caused by the angle variation of the incident wave. The research result shows that the plane beam signal illuminates the target uniformly in space, can eliminate the discontinuity in profile data caused by the directivity of the antenna, improve the stability and quality of the echo signal, and enrich the target response parameters.

关键词： Plane beam signals Ground penetrating radar array (GPR array) Finite difference time domain (FDTD) recursive convolution Complex frequency shift-perfect matching layer (CFS-PML)

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Higher-Order convolution PML (CPML) for FDTD Electromagnetic Modeling

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 2020年第8期68卷 6226-6231页

作者： Giannopoulos, Antonios Univ Edinburgh Inst Infrastruct & Environm Sch Engn Edinburgh EH9 3FG Midlothian Scotland

A new simple formulation for incorporating a higher-order perfectly matched layer (PML) stretching function within a convolution PML (CPML) implementation in finite-difference time-domain (FDTD) electromagnetic modeling codes is developed. Obtaining in closed form the corresponding time domain impulse response of the inverse of a number of higher-order PML stretching functions enables the efficient and simple implementation of such higher-order PMLs using recursive convolution, in the same way as it was introduced initially for the complex frequency shifted (CFS) PML. This new higher-order CPML exhibits excellent performance that is comparable to the performance shown by other higher-order PML formulations whilst it retains the advantage of a relatively simpler implementation.

关键词： Time-domain analysis Finite difference methods convolution Antennas Standards Frequency-domain analysis Numerical stability Absorbing boundary conditions finitedifference time-domain (FDTD) finite difference methods perfectly matched layer (PML) recursive convolution

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A constant recursive convolution technique for frequency dependent scalar wave equation based FDTD algorithm

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JOURNAL OF COMPUTATIONAL ELECTRONICS 2013年第4期12卷 752-756页

作者： Ozakin, M. Burak Aksoy, Serkan Gebze Inst Technol Dept Elect Engn Kocaeli Turkey

A scalar wave equation based recursive convolution finite-difference time-domain algorithm is developed for a frequency-dependent Debye medium in this paper. This algorithm is based on a recursive evaluation of a convolution integral in the time domain. A numerical example is presented for a problem of wide-band reflection from an air-water interface. The obtained results are compared with an analytical solution. The excellent agreement is observed between the numerical results. Memory and computational time advantages of the proposed method over Maxwell's equations based solution are also shown.

关键词： Dispersive medium Finite difference time domain method recursive convolution

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recursive implicit time domain technique for modeling dispersive materials

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OPTICAL AND QUANTUM ELECTRONICS 2020年第3期52卷 1-7页

作者： Akond, M. S. Najran Univ Coll Engn Najran Saudi Arabia

Short pulse propagation inside a frequency-dependent Debye medium is studied by developing an algorithm for the solution of wave equation using recursive time-domain beam propagation method. Being an implicit and recursive technique, it is compared with other existing similar techniques, such as recursive finite difference time domain and time domain beam propagation method. The developed technique avoids matrix inversion though a considerable numerical dispersion is observed. The numerical dispersion is assessed and superseded through an empirical relation. The prominent benefit of this technique is that it is stable for multi-pole Debye medium even at high time steps with relaxed mesh-grid.

关键词： recursive convolution Auxiliary differential equation Dispersion Multipole Debye medium

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High-order accurate FDTD schemes for dispersive Maxwell's equations in second-order form using recursive convolutions

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2018年 336卷 192-218页

作者： Jenkinson, M. J. Banks, J. W. Rensselaer Polytech Inst Dept Math Sci Troy NY 12180 USA

We propose a novel finite-difference time-domain (FDTD) scheme for the solution of Maxwell's equations in which linear dispersive effects are present. The method uses high-order accurate approximations in space and time for the dispersive Maxwell's equations written as a second-order vector wave equation with a time-history convolution term. The modified equation approach is combined with the recursive convolution (RC) method to develop high-order approximations accurate to any desired order in space and time. High-order-accurate centered approximations of the physical Maxwell interface conditions are derived for the dispersive setting in order to fully restore accuracy at discontinuous material interfaces. Second- and fourth-order accurate versions of the scheme are presented and implemented in two spatial dimensions for the case of the Drude linear dispersion model. The stability of these schemes is analyzed. Finally, our approach is also amenable to curvilinear numerical grids if used with an appropriate generalized Laplace operator. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Dispersive Maxwell FDTD recursive convolution Wave equations

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A Method for the Evaluation of Cooray-Rubinstein Formula Based on Talbot's Method for Numerical Inverse Laplace Transform

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IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY 2019年第3期61卷 759-765页

作者： Liu, Xin Zhang, Mengmeng Wang, Pai Niu, Shengsuo North China Elect Power Univ Key Lab Distributed Energy Storage & Microgrid He Baoding 071003 Peoples R China

The Cooray-Rubinstein formula (C-R formula) has been widely used to calculate the horizontal electric field generated by a lightning return stroke over the lossy ground. To evaluate the time-domain C-R formula by a recursive convolution, an alternative method is proposed in this paper, where the formulation in terms of the "step response" corresponding to the ground surface impedance, denoted as k(epsilon) (t), is evaluated by the numerical inverse Laplace transform (NILT). Considering the good performance of Talbot's method for the NILT, Talbot's method is adopted to express ke(t) in terms of a series of exponential functions, which can avoid the tedious piecewise approximation used by the available method and make the recursive convolution easier to program. In addition, some key formulae for the recursive convolution with complex poles and residues are presented in this paper. Numerical examples are provided to validate the proposed method.

关键词： Electromagnetic fields lightning numerical inverse Laplace transform (NILT) recursive convolution Talbot's method

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