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Full-Text Articles in Engineering
Enhanced Pml Based On The Long Short Term Memory Network For The Fdtd Method, He Ming Yao, Lijun Jiang
Enhanced Pml Based On The Long Short Term Memory Network For The Fdtd Method, He Ming Yao, Lijun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
This paper proposes a new absorbing boundary condition (ABC) computation approach based on the deep learning technique. Benefited from the sequence dependence feature, the Long Short-Term Memory (LSTM) network is employed to replace the conventional perfectly matched layer (PML) ABC for the Finite-Difference Time-Domain (FDTD) solving process. The newly proposed LSTM based PML model is trained by the electromagnetic field data on the interface of the conventional PML. Different from the conventional PML, the newly proposed model only needs one cell layer as the boundary. Hence, the newly proposed method conveniently reduces both the algorithm's complexity and the area of …
Machine Learning Methodology Review For Computational Electromagnetics, He Ming Yao, Lijun Jiang, Huan Huan Zhang, Wei E.I. Sha
Machine Learning Methodology Review For Computational Electromagnetics, He Ming Yao, Lijun Jiang, Huan Huan Zhang, Wei E.I. Sha
Electrical and Computer Engineering Faculty Research & Creative Works
While machine learning is revolutionizing every corner of modern technologies, we have been attempting to explore whether machine learning methods could be used in computational electromagnetic (CEM). In this paper, five efforts in line with this direction are reviewed. They include forward methods such as the method of moments (MoM) solved by the artificial neural network training process, FDTD PML (perfectly matched layer) using the hyperbolic tangent basis function (HTBF), etc. There are also inverse problems that use the deep ConvNets for the effective source reconstruction and subwavelength imaging in the far-field. Benchmarks are provided to demonstrate the feasibility of …
Machine Learning Based Neural Network Solving Methods For The Fdtd Method, He Ming Yao, Li (Lijun) Jun Jiang
Machine Learning Based Neural Network Solving Methods For The Fdtd Method, He Ming Yao, Li (Lijun) Jun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, two novel computational processes are proposed to solve Finite-Difference Time-Domain (FDTD) based on machine learning deep neural networks. The field and boundary conditions are employed to establish recurrent neural network FDTD (RNN-FDTD) model and convolution neural network FDTD (CNN-FDTD) model respectively. Numerical examples from scalar wave equations are provided to benchmark the performance of the proposed methods. The results demonstrate that the newly proposed methods could solve FDTD steps with satisfactory accuracy. According to our knowledge, these are unreported new approaches for machine learning based FDTD solving methods.
Optimization Of Patch Antennas Via Multithreaded Simulated Annealing Based Design Exploration, James E. Richie, Cristinel Ababei
Optimization Of Patch Antennas Via Multithreaded Simulated Annealing Based Design Exploration, James E. Richie, Cristinel Ababei
Electrical and Computer Engineering Faculty Research and Publications
In this paper, we present a new software framework for the optimization of the design of microstrip patch antennas. The proposed simulation and optimization framework implements a simulated annealing algorithm to perform design space exploration in order to identify the optimal patch antenna design. During each iteration of the optimization loop, we employ the popular MEEP simulation tool to evaluate explored design solutions. To speed up the design space exploration, the software framework is developed to run multiple MEEP simulations concurrently. This is achieved using multithreading to implement a manager-workers execution strategy. The number of worker threads is the same …
Improvement Of Solar Cell Efficiency Using Nano-Scale Top And Bottom Grating, Xiaomin Jin, Ashton Ellaboudy, Greg Chavoor
Improvement Of Solar Cell Efficiency Using Nano-Scale Top And Bottom Grating, Xiaomin Jin, Ashton Ellaboudy, Greg Chavoor
Electrical Engineering
We study solar-cell designs using nano-grating on both top (transmission) and bottom (reflection) of the solar cell. First, we perform simulations based on rigorous coupled wave analysis (RCWA) to evaluate the diffraction top gratins. In RCWA method, we calculate up to 20 harmonics, and sweep the launch angle of incident light from 0 to 90 degree. The incident light varies from100nm to 1200nm wavelength. Triangular grating can achieve higher light absorption compared to the rectangular grating. The best top grating is around 200nm grating period, 100nm grating height, and 50% filling factor, which responses to 37% improvement for triangular grating …
Discrete Coordinate Transformation For Designing All-Dielectric Flat Antennas, Wenxuan Tang, Christos Argyropoulos, Efthymios Kallos, Wei Song, Yang Hao
Discrete Coordinate Transformation For Designing All-Dielectric Flat Antennas, Wenxuan Tang, Christos Argyropoulos, Efthymios Kallos, Wei Song, Yang Hao
Department of Electrical and Computer Engineering: Faculty Publications
Transformation electromagnetics provides a practical approach to control electromagnetic fields at will. Based on this principle, novel devices such as the invisible cloak have been proposed. Here we examine the extension of this technique as applied to the design of flat devices in antenna systems. A method using discrete coordinate transformation is proposed, which allows the conversion of conventional devices with curved shapes into flat systems, while preserving their non-dispersive, isotropic, broadband, and lossless properties. Two specific design examples, a flat reflector and a flat lens embedded in free space, are presented. To avoid the loss and narrow bandwidth issues …
Numerical Analysis Of Sandwiched Composite-Fss Structures, Qiang Rui, Chen Ji, Huang Jingyu, Maria Koledintseva, Richard E. Dubroff, James L. Drewniak, Yang Fan
Numerical Analysis Of Sandwiched Composite-Fss Structures, Qiang Rui, Chen Ji, Huang Jingyu, Maria Koledintseva, Richard E. Dubroff, James L. Drewniak, Yang Fan
Electrical and Computer Engineering Faculty Research & Creative Works
A numerical technique to analyze shielding effectiveness of sandwiched FSS-composite structures is proposed. This technique is based on using a dispersive FDTD method in conjuncture with a novel periodic boundary condition to model sandwiched FSS-composite elements. Results show that by inserting single or multilayered FSS elements into composite materials, better shielding effectiveness can be achieved. © 2006 IEEE.
Characterizing Package/Pcb Pdn Interactions From A Full-Wave Finite-Difference Formulation, Shishuang Sun, David Pommerenke, James L. Drewniak, Kai Xiao, Sin-Ting Chen, Tzong-Lin Wu
Characterizing Package/Pcb Pdn Interactions From A Full-Wave Finite-Difference Formulation, Shishuang Sun, David Pommerenke, James L. Drewniak, Kai Xiao, Sin-Ting Chen, Tzong-Lin Wu
Electrical and Computer Engineering Faculty Research & Creative Works
A novel approach of equivalent circuit model extraction is developed for modeling of integrated package and PCB power distribution networks (PDN). The integrated PDNs are formulated from a full-wave finite-difference algorithm, and the resulting matrix equations are converted to equivalent circuits. The equivalent circuits, as well as the decoupling capacitors and the attached circuit components, can be analyzed with a SPICE-like solver in both the time and frequency domains. The modeling of dielectric loss is also addressed. The method is used to model three PDN problems including a simple power bus, a BGA package mounting on a PCB, and a …
Numerical Analysis Of Sandwiched Composite-Fss Structures, Rui Qiang, Ji Chen, Jingyu Huang, Marina Koledintseva, Richard E. Dubroff, James L. Drewniak, Fan Yang
Numerical Analysis Of Sandwiched Composite-Fss Structures, Rui Qiang, Ji Chen, Jingyu Huang, Marina Koledintseva, Richard E. Dubroff, James L. Drewniak, Fan Yang
Electrical and Computer Engineering Faculty Research & Creative Works
A numerical technique to analyze shielding effectiveness of sandwiched FSS-composite structures is proposed. This technique is based on using a dispersive FDTD method in conjuncture with a novel periodic boundary condition to model sandwiched FSS-composite elements. Results show that by inserting single or multilayered FSS elements into composite materials, better shielding effectiveness can be achieved.
A Three-Dimensional Fdtd Subgridding Method With Separate Spatial And Temporal Subgridding Interfaces, Kai Xiao, David Pommerenke, James L. Drewniak
A Three-Dimensional Fdtd Subgridding Method With Separate Spatial And Temporal Subgridding Interfaces, Kai Xiao, David Pommerenke, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
The idea of separating the spatial and temporal subgridding interfaces is introduced in this paper. Based on this idea, the spatial and temporal subgridding algorithms can be developed and analyzed separately. The spatial algorithm was given in the previous paper. In this paper, the temporal subgridding algorithm is described and the stability is illustrated by the analytical formulation of a one-dimensional model. An FDTD code that combines the spatial and temporal subgridding algorithms is implemented. Numerical test models are calculated to show the stability and accuracy of the proposed method.
A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak
A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
A three-dimensional subgridding algorithm for the finite difference time domain (FDTD) method is proposed in this paper. The method is based on interpolation of electric and magnetic current densities. The coarse-fine mesh ratio can be either 1:2 or 1:3. Results of a test model utilizing a lossless cavity excited with a dipole show no tendency of instability after 500000 time steps. The reflection in time domain at the subgridding interface was calculated to test the accuracy of the subgridding algorithm.
Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen
Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen
Electrical and Computer Engineering Faculty Research & Creative Works
A dual-step MTL / FDTD strategy is proposed for anticipating full-vehicle level EMI. In the first step, the current distribution along a cable bundle connecting to electronic modules an an automotive platform is calculated using multi-conductor transmission-line (MTL) models. In order to account for common-mode discontinuities on the vehicle chassis, e.g., slots, 3D full-wave modeling (FDTD) is used to determine radiation impedances, which are thereafter incorporated in the MTL models for compensating the radiation power loss. In the second step, the obtained currents are implemented as impressed current sources in full-vehicle full-wave modeling using an FDTD multi-wire subcelluar algorithm. Thus, …
Using Near-Field Scanning To Predict Radiated Fields, Jin Shi, Michael A. Cracraft, Jianmin Zhang, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi
Using Near-Field Scanning To Predict Radiated Fields, Jin Shi, Michael A. Cracraft, Jianmin Zhang, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi
Electrical and Computer Engineering Faculty Research & Creative Works
Near-field scanning has often been used to measure and characterize magnetic fields surrounding individual integrated circuits (IC) and high speed digital electronic circuits. The paper describes the use of near-field scanning data, performed in a typical laboratory bench top environment, to predict radiated electromagnetic interference (EMI) in a typical product environment. The product environment may include enclosures and apertures. The approach begins by acquiring sufficient near-field scanning data to allow representation of an unintentional radiating source by an equivalent surface current distribution. The equivalent current distribution is used as a source in numerical full wave modeling. The agreement between direct …
Fdtd Method Capable Of Attaching Rectangular Domains, Kai Xiao, David Pommerenke, James L. Drewniak
Fdtd Method Capable Of Attaching Rectangular Domains, Kai Xiao, David Pommerenke, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
A finite-difference time-domain (FDTD) method capable of attaching rectangular computational domains is proposed herein. The aim of this approach is to reduce the size of computational domain according to the geometry of the modeled structure so as to reduce the simulation time with keeping precision of the result in an acceptable range. A multigrid algorithm is applied on the attaching interface between two rectangular domains so that different resolution can be achieved in different domains.
Numerical Modeling Of Electrostatic Discharge Generators, Kai Wang, David Pommerenke, Ramachandran Chundru, Thomas Van Doren, James L. Drewniak, A. Shashindranath
Numerical Modeling Of Electrostatic Discharge Generators, Kai Wang, David Pommerenke, Ramachandran Chundru, Thomas Van Doren, James L. Drewniak, A. Shashindranath
Electrical and Computer Engineering Faculty Research & Creative Works
The discharge current and the transient fields of an electrostatic discharge (ESD) generator in the contact mode are numerically simulated using the finite-difference time-domain method. At first the static field is established. Then the conductivity of the relay contact is changed, which initiates the discharge process. The simulated data are used to study the effect of design choices on the current and fields. They are compared to measured field and current data using multidecade broadband field and current sensors. The model allows accurate prediction of the fields and currents of ESD generators, thus it can be used to evaluate different …
A Study Of The Probe Induced Disturbances On The Near-Field Measurement, Jin Shi, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi, K.-I. Arai
A Study Of The Probe Induced Disturbances On The Near-Field Measurement, Jin Shi, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi, K.-I. Arai
Electrical and Computer Engineering Faculty Research & Creative Works
Numerical simulations were used to investigate the disturbance introduced by placing a small magnetic loop probe in the near field of a driven loop. In the absence of the loop probe, the numerical simulations were compared with an approximate closed-form analytical expression for the magnetic field produced by the driven loop. The agreement between the approximate analytical results and the simulation was good. The next set of simulations was based on a physical model that included the probe and showed that the probe does exert an effect on the field being measured. Examples of these simulations and their implications on …
Fdtd Data Extrapolation Using Multilayer Perceptron (Mlp), H. Goksu, David Pommerenke, Donald C. Wunsch
Fdtd Data Extrapolation Using Multilayer Perceptron (Mlp), H. Goksu, David Pommerenke, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
This work compares MLP with the matrix pencil method, a linear eigenanalysis-based extrapolator, in terms of their effectiveness in finite difference time domain (FDTD) data extrapolation. Matrix pencil method considers the signal as superposed complex exponentials while MLP considers each time step to be a nonlinear function of previous time steps.
Transmission Line Modeling Of Vias In Differential Signals, Chen Wang, James L. Drewniak, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander
Transmission Line Modeling Of Vias In Differential Signals, Chen Wang, James L. Drewniak, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander
Electrical and Computer Engineering Faculty Research & Creative Works
Signal layer transitions in differential lines are modeled using both FDTD and equivalent circuit methods. The equivalent circuit is developed based on transmission-line reasoning regarding via behavior. Parameters of each transmission-line segment are obtained based on its corresponding physical geometry. The mixed-mode S-parameters from the equivalent circuit and the FDTD modeling are compared. Good agreement is demonstrated in the frequency range from 1 GHz to 20 GHz. The results indicate that vias in differential lines can be modeled as a transmission line for a quick and easy engineering estimation of the differential signal behavior in an environment of signal layer …
Anticipating Full Vehicle Radiated Emi From Module-Level Testing In Automobiles, Geping Liu, Chingchi Chen, Yuhua Tu, James L. Drewniak
Anticipating Full Vehicle Radiated Emi From Module-Level Testing In Automobiles, Geping Liu, Chingchi Chen, Yuhua Tu, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
EMI due to common-mode currents on cables routed in automobiles was studied using a test device designed to mimic a vehicle. Both experimental work and Finite-Difference Time-Domain (FDTD) modeling were employed in this paper. The good agreement between the measurements and modeling results indicates that the numerical tools can be a useful aid in predicting vehicle-level EMI by developing vehicle transfer functions and measuring the module-level EMI characteristics on the bench top.
Efficient Modeling Of Discontinuities And Dispersive Media In Printed Transmission Lines, R. Araneo, Chen Wang, Xiaoxiong Gu, James L. Drewniak, S. Celozzi
Efficient Modeling Of Discontinuities And Dispersive Media In Printed Transmission Lines, R. Araneo, Chen Wang, Xiaoxiong Gu, James L. Drewniak, S. Celozzi
Electrical and Computer Engineering Faculty Research & Creative Works
The finite-difference time-domain method is applied to the analysis of transmission lines on printed circuit boards. The lossy, dispersive behavior of the dielectric substrate is accurately accounted for by means of several algorithms whose accuracy is discussed and compared. Numerical results are validated by comparisons with measurements and an equivalent circuit of slot in the ground plane is proposed.
Grounding Of Heatpipe/Heatspreader And Heatsink Structures For Emi Mitigation, Chen Wang, James L. Drewniak, D. Wang, Ray Alexander, James L. Knighten, David M. Hockanson
Grounding Of Heatpipe/Heatspreader And Heatsink Structures For Emi Mitigation, Chen Wang, James L. Drewniak, D. Wang, Ray Alexander, James L. Knighten, David M. Hockanson
Electrical and Computer Engineering Faculty Research & Creative Works
EMI problems caused by the presence of heatpipe/heatspreader and heatsink structures in a high-speed design are well known in engineering practice. High-frequency noise can be coupled from IC packages to an electrically conductive heatsink or heatspreader attached to the IC, which then is radiated, or the energy coupled to an enclosure cavity mode. This EMI coupling path was modeled with the finite-difference time-domain (FDTD) method, and a mitigation approach was investigated. Good agreement between measurements and FDTD modeling is demonstrated, indicating FDTD is a suitable tool for analysis and design. Then, several grounding schemes suitable for a heatsink or heatspreader …
Fdtd And Experimental Investigation Of Emi From Stacked-Card Pcb Configurations, David M. Hockanson, Xiaoning Ye, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff
Fdtd And Experimental Investigation Of Emi From Stacked-Card Pcb Configurations, David M. Hockanson, Xiaoning Ye, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff
Electrical and Computer Engineering Faculty Research & Creative Works
Stacked-card and modules-on-backplane printed circuit-board geometries are advantageous for conserving real-estate in many designs. Unfortunately, at high frequencies, electromagnetic magnetic interference (EMI) resulting from the nonnegligible impedance of the signal return at the connector may occur. This effective EMI coupling path results in the daughtercard being driven against the motherboard and attached cables, resulting in common-mode radiation. The connector geometry can be modified to minimize the EMI coupling path when high frequencies are routed between the motherboard and daughtercard. Current speeds and printed circuit board (PCB) sizes result in geometries that are of significant dimensions in terms of a wavelength …
Incorporating Two-Port Networks With S-Parameters Into Fdtd, Xiaoning Ye, James L. Drewniak
Incorporating Two-Port Networks With S-Parameters Into Fdtd, Xiaoning Ye, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
A modeling approach for incorporating a two-port network with S-parameters in the finite-difference time-domain (FDTD) method is reported in this paper. The proposed method utilizes the time-domain Y-parameters to describe the network characteristics, and incorporates the Y-parameters into the FDTD algorithm. The generalized pencil-of-function (GPOF) technique is applied to improve the memory efficiency of this algorithm by generating a complex exponential series for the Y-parameters and using recursive convolution in the FDTD updating equations. A modeling example is given, which shows that this approach is effective and accurate. This modeling technique can be extended for incorporating any number of N-port …
Emi From Airflow Aperture Arrays In Shielding Enclosures-Experiments, Fdtd, And Mom Modeling, Min Li, Joe Nuebel, James L. Drewniak, Richard E. Dubroff, Todd H. Hubing, Thomas Van Doren
Emi From Airflow Aperture Arrays In Shielding Enclosures-Experiments, Fdtd, And Mom Modeling, Min Li, Joe Nuebel, James L. Drewniak, Richard E. Dubroff, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Aperture arrays designed to provide airflow through shielding enclosures can provide part of the coupling path from interior sources to external electromagnetic interference (EMI). In this work, radiation through aperture arrays is investigated numerically and experimentally. FDTD modeling is compared with measurements on aperture arrays in a test enclosure. The method of moments (MoM) is also utilized to study radiation from apertures and to investigate the mutual coupling between apertures in an infinite conducting plane. A simple design equation for the relation between aperture size and number and shielding effectiveness is proposed.
Numerical And Experimental Corroboration Of An Fdtd Thin-Slot Model For Slots Near Corners Of Shielding Enclosures, Min Li, Kuang-Ping Ma, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Numerical And Experimental Corroboration Of An Fdtd Thin-Slot Model For Slots Near Corners Of Shielding Enclosures, Min Li, Kuang-Ping Ma, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Simple design maxims to restrict slot dimensions in enclosure designs below a half-wave length are not always adequate for minimizing electromagnetic interference (EMI). Complex interactions between cavity modes, sources, and slots can result in appreciable radiation through nonresonant length slots. The finite-difference time domain (FDTD) method can be employed to pursue these issues with adequate modeling of thin slots. Subcellular FDTD algorithms for modeling thin slots in conductors have previously been developed. One algorithm based on a quasistatic approximation has been shown to agree well with experimental results for thin slots in planes. This FDTD thin-slot algorithm is compared herein …
Comparison Of Fdtd Algorithms For Subcellular Modeling Of Slots In Shielding Enclosures, Kuang-Ping Ma, Min Li, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Comparison Of Fdtd Algorithms For Subcellular Modeling Of Slots In Shielding Enclosures, Kuang-Ping Ma, Min Li, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Subcellular modeling of thin slots in the finite-difference time-domain (FDTD) method is investigated. Two subcellular algorithms for modeling thin slots with the FDTD method are compared for application to shielding end osures in electromagnetic compatibility (EMC). The stability of the algorithms is investigated, and comparisons between the two methods for slots in planes, and slots in loaded cavities are made. Results for scattering from a finite-length slot in an infinite plane employing one of the algorithms are shown to agree well with published experimental results, and power delivered to an enclosure with a slot agree well with results measured for …
A Comparison Of An Fdtd Thin-Slot Algorithm And Method Of Moments For Modeling Slots Near Corners, Kuang-Ping Ma, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
A Comparison Of An Fdtd Thin-Slot Algorithm And Method Of Moments For Modeling Slots Near Corners, Kuang-Ping Ma, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Subcellular FDTD algorithms for modeling thin slots in conductors have previously been developed. One algorithm that is based on a quasi-static approximation has been shown to agree well with experimental results for thin slots in planes. This FDTD thin-slot algorithm is compared herein with moment method results for thin slots near corners.