Pub Date : 2023-03-30DOI: 10.1109/JMMCT.2023.3263152
Jon T. Kelley;Ali E. Yılmaz;Yaniv Brick
An easy-to-implement iterative algorithm that enables efficient and scalable spectral analysis of dense matrices is presented. The algorithm relies on the approximation of a matrix's singular values by those of a series of smaller matrices formed from uniform random sampling of its rows and columns. It is shown that, for sufficiently incoherent and rank-deficient matrices, the singular values [are expected to] decay at the same rate as those of matrices formed via this sampling scheme, which permits such matrices’ ranks to be accurately estimated from the smaller matrices’ spectra. Moreover, for such a matrix of size $m times n$ , it is shown that the dominant singular values are [expected to be] $sqrt {mn} /k$ times those of a $k times k$ matrix formed by randomly sampling $k$ of its rows and columns. Starting from a small initial guess $k = {k}_0$ , the algorithm repeatedly doubles $k$ until two convergence criteria are met; the criteria to ensure that $k$ is sufficiently large to estimate the singular values, to the desired accuracy, are presented. The algorithm's properties are analyzed theoretically and its efficacy is studied numerically for small to very-large matrices that result from discretization of integral-equation operators, with various physical kernels common in electromagnetics and acoustics, as well as for artificial matrices of various incoherence and rank-deficiency properties.
{"title":"An Iterative Random Sampling Algorithm for Rapid and Scalable Estimation of Matrix Spectra","authors":"Jon T. Kelley;Ali E. Yılmaz;Yaniv Brick","doi":"10.1109/JMMCT.2023.3263152","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3263152","url":null,"abstract":"An easy-to-implement iterative algorithm that enables efficient and scalable spectral analysis of dense matrices is presented. The algorithm relies on the approximation of a matrix's singular values by those of a series of smaller matrices formed from uniform random sampling of its rows and columns. It is shown that, for sufficiently incoherent and rank-deficient matrices, the singular values [are expected to] decay at the same rate as those of matrices formed via this sampling scheme, which permits such matrices’ ranks to be accurately estimated from the smaller matrices’ spectra. Moreover, for such a matrix of size \u0000<inline-formula><tex-math>$m times n$</tex-math></inline-formula>\u0000, it is shown that the dominant singular values are [expected to be] \u0000<inline-formula><tex-math>$sqrt {mn} /k$</tex-math></inline-formula>\u0000 times those of a \u0000<inline-formula><tex-math>$k times k$</tex-math></inline-formula>\u0000 matrix formed by randomly sampling \u0000<inline-formula><tex-math>$k$</tex-math></inline-formula>\u0000 of its rows and columns. Starting from a small initial guess \u0000<inline-formula><tex-math>$k = {k}_0$</tex-math></inline-formula>\u0000, the algorithm repeatedly doubles \u0000<inline-formula><tex-math>$k$</tex-math></inline-formula>\u0000 until two convergence criteria are met; the criteria to ensure that \u0000<inline-formula><tex-math>$k$</tex-math></inline-formula>\u0000 is sufficiently large to estimate the singular values, to the desired accuracy, are presented. The algorithm's properties are analyzed theoretically and its efficacy is studied numerically for small to very-large matrices that result from discretization of integral-equation operators, with various physical kernels common in electromagnetics and acoustics, as well as for artificial matrices of various incoherence and rank-deficiency properties.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-23DOI: 10.1109/JMMCT.2023.3260900
Mengmeng Li;Zixuan Ma
Three different deep learning models were designed in this paper, to predict the electric fields of single nanoparticles, dimers, and nanoparticle arrays. For single nanoparticles, the prediction error was 4.4%. For dimers with strong couplings, a sample self-normalization method was proposed, and the error was reduced by an order of magnitude compared with traditional methods. For nanoparticle arrays, the error was reduced from 28.8% to 5.6% compared with previous work. Numerical tests proved the validity of the proposed deep learning models, which have potential applications in the design of nanostructures.
{"title":"Accurate Prediction of Electric Fields of Nanoparticles With Deep Learning Methods","authors":"Mengmeng Li;Zixuan Ma","doi":"10.1109/JMMCT.2023.3260900","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3260900","url":null,"abstract":"Three different deep learning models were designed in this paper, to predict the electric fields of single nanoparticles, dimers, and nanoparticle arrays. For single nanoparticles, the prediction error was 4.4%. For dimers with strong couplings, a sample self-normalization method was proposed, and the error was reduced by an order of magnitude compared with traditional methods. For nanoparticle arrays, the error was reduced from 28.8% to 5.6% compared with previous work. Numerical tests proved the validity of the proposed deep learning models, which have potential applications in the design of nanostructures.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-11DOI: 10.1109/JMMCT.2023.3275321
Walid Dirahoui;Hocine Menana
This article presents a numerical and experimental studies on the non-destructive testing of high temperature superconducting (HTS) multilayer tapes at room temperature, by eddy current thermography (ECT). An experimental setup is developed in which a rotating magnet wheel inductor is used instead of electromagnetic inductors to avoid the inherent thermal disturbance. A 3-D magnetothermal modelling approach is developed for the verification of the experimental results and the simulation of situations that cannot be reproduced experimentally, in particular the verification of the detection limits as a function of the shape and location of the defects. Simulation and experimental results are in good agreement.
{"title":"Numerical and Experimental Investigations of Flaws Detection in Multilayer HTS Tapes by Magnetothermal Technique","authors":"Walid Dirahoui;Hocine Menana","doi":"10.1109/JMMCT.2023.3275321","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3275321","url":null,"abstract":"This article presents a numerical and experimental studies on the non-destructive testing of high temperature superconducting (HTS) multilayer tapes at room temperature, by eddy current thermography (ECT). An experimental setup is developed in which a rotating magnet wheel inductor is used instead of electromagnetic inductors to avoid the inherent thermal disturbance. A 3-D magnetothermal modelling approach is developed for the verification of the experimental results and the simulation of situations that cannot be reproduced experimentally, in particular the verification of the detection limits as a function of the shape and location of the defects. Simulation and experimental results are in good agreement.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-10DOI: 10.1109/JMMCT.2023.3255010
Sheldon R. Steines;Brett L. Baxley;Andrew F. Peterson
The performance of several inexpensive local error estimation techniques is evaluated in connection with the Rao-Wilton-Glisson method of moments numerical solutions of the electric field integral equation. Results for 18 perfectly conducting test targets are used to evaluate the performance of the estimators. Two of the estimators produce error maps that consistently exhibit high correlations with reference solutions. These estimators are also suitable for “goal-oriented” estimation of secondary quantities, such as identifying cells that contribute the most error to the radar cross section of the target.
{"title":"Performance of Inexpensive Local Error Estimation Techniques for Integral Equation Numerical Solutions","authors":"Sheldon R. Steines;Brett L. Baxley;Andrew F. Peterson","doi":"10.1109/JMMCT.2023.3255010","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3255010","url":null,"abstract":"The performance of several inexpensive local error estimation techniques is evaluated in connection with the Rao-Wilton-Glisson method of moments numerical solutions of the electric field integral equation. Results for 18 perfectly conducting test targets are used to evaluate the performance of the estimators. Two of the estimators produce error maps that consistently exhibit high correlations with reference solutions. These estimators are also suitable for “goal-oriented” estimation of secondary quantities, such as identifying cells that contribute the most error to the radar cross section of the target.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A parallel multiphysics simulation solver is developed to solve electromagnetic-thermal-mechanical coupling for some challenging large-scale antenna arrays. To achieve high scalability of supercomputer architectures, we reconstruct the preconditioned BiCGSTAB method and the non-overlapping domain decomposition method, so that the most resource-intensive matrix factorization steps can be performed in parallel independently within subdomains. The electromagnetic and thermal fields are solved separately, while coupled through the dissipated power and the temperature-dependent material parameters; after thermal steady state is reached, the mechanical simulation is stimulated subject to the temperature rise. The accuracy of electromagnetic-thermal coupling and thermal stress solution are first validated, and then the strong/weak parallel scalability experiments of the developed multiphysics solver are performed on supercomputer. Finally, an extremely challenging antenna array is simulated using the proposed solver, where to our best knowledge we bring the scale of multiphysics simulations excited by frequency-domain electromagnetic fields to the order of billion unknowns for the first time.
{"title":"Multiphysics Computing of Challenging Antenna Arrays Under a Supercomputer Framework","authors":"Hao-Xuan Zhang;Qiwei Zhan;Li Huang;Da-Wei Wang;Yin-Da Wang;Wei-Jie Wang;Zhen-Guo Zhao;Hai-Jing Zhou;Kai Kang;Liang Zhou;Wen-Yan Yin","doi":"10.1109/JMMCT.2023.3254661","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3254661","url":null,"abstract":"A parallel multiphysics simulation solver is developed to solve electromagnetic-thermal-mechanical coupling for some challenging large-scale antenna arrays. To achieve high scalability of supercomputer architectures, we reconstruct the preconditioned BiCGSTAB method and the non-overlapping domain decomposition method, so that the most resource-intensive matrix factorization steps can be performed in parallel independently within subdomains. The electromagnetic and thermal fields are solved separately, while coupled through the dissipated power and the temperature-dependent material parameters; after thermal steady state is reached, the mechanical simulation is stimulated subject to the temperature rise. The accuracy of electromagnetic-thermal coupling and thermal stress solution are first validated, and then the strong/weak parallel scalability experiments of the developed multiphysics solver are performed on supercomputer. Finally, an extremely challenging antenna array is simulated using the proposed solver, where to our best knowledge we bring the scale of multiphysics simulations excited by frequency-domain electromagnetic fields to the order of billion unknowns for the first time.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-03DOI: 10.1109/JMMCT.2023.3252053
Shuai S. A. Yuan;Zhu Hong Lin;Li-Bin Lv;Shu-Ji Hao;Wei E. I. Sha
The artificial field-aligned irregularity (AFAI) in ionosphere can be generated by heating the ionosphere with high-power high-frequency radio waves, and the physical structures of AFAIs are modeled as elongated multiple multilayer plasma cylinders. At relatively low frequencies, AFAIs could work as natural reflectors for long-distance communications. In order to evaluate the performance of AFAI-based communications, it is crucial to obtain the objective radar cross section (RCS) of AFAIs quickly and accurately. On account of the large electrical size of AFAIs, it would be time-consuming to calculate the objective RCS by full-wave simulations, meanwhile, the accuracies of the existing approximated methods are limited in many scenarios. In this paper, the T-matrix algorithm is used for analytically calculating the objective RCS of AFAIs after making reasonable approximations. Compared to the results obtained from full-wave simulations, the errors of objective RCS are within an acceptable range while the computation time is largely reduced. Furthermore, the scattering characteristics of AFAIs at different frequencies are investigated. The proposed method could be readily implemented for investigating and predicting the performance of AFAI-based long-wave communications.
{"title":"Investigating the Scattering Characteristics of Artificial Field-Aligned Irregularities Based on T-Matrix Algorithm","authors":"Shuai S. A. Yuan;Zhu Hong Lin;Li-Bin Lv;Shu-Ji Hao;Wei E. I. Sha","doi":"10.1109/JMMCT.2023.3252053","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3252053","url":null,"abstract":"The artificial field-aligned irregularity (AFAI) in ionosphere can be generated by heating the ionosphere with high-power high-frequency radio waves, and the physical structures of AFAIs are modeled as elongated multiple multilayer plasma cylinders. At relatively low frequencies, AFAIs could work as natural reflectors for long-distance communications. In order to evaluate the performance of AFAI-based communications, it is crucial to obtain the objective radar cross section (RCS) of AFAIs quickly and accurately. On account of the large electrical size of AFAIs, it would be time-consuming to calculate the objective RCS by full-wave simulations, meanwhile, the accuracies of the existing approximated methods are limited in many scenarios. In this paper, the T-matrix algorithm is used for analytically calculating the objective RCS of AFAIs after making reasonable approximations. Compared to the results obtained from full-wave simulations, the errors of objective RCS are within an acceptable range while the computation time is largely reduced. Furthermore, the scattering characteristics of AFAIs at different frequencies are investigated. The proposed method could be readily implemented for investigating and predicting the performance of AFAI-based long-wave communications.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-06DOI: 10.1109/JMMCT.2023.3242714
Yuhang Dou;Hao Chen
A method of analyzing characteristic modes (CMs) of antennas with multiple lumped LC loads is proposed based on the full-wave generalized partial element equivalent circuit (GPEEC) model. Different with traditional CMs analysis methods, this method can be integrated into an optimization algorithm. With this powerful engine, we can develop a systematic method to manipulate radiation CMs of a mobile terminal while preserving its aesthetic structure features of the industrial design. This method can reveal all possible radiation structure performances as traditional methods and even create new possible radiation modes to improve antenna performance. With the GPEEC model, a comprehensive analysis of antennas can be achieved simultaneously, including but not limited to simulating time-/frequency-domain responses, evaluating radiation efficiency contributed by the self- and mutual radiated power separately, and plotting current and field distribution. Three design examples are demonstrated, including analyzing the working mechanism of the self-curing decoupling technique for mobile terminals from the view of CMs, extending the bandwidth of an antenna in LTE-A low-frequency bands, and creating a pair of MIMO antennas in the low LTE-A bands. These examples are verified theoretically and experimentally, showing the high potential of this method in analyzing and designing antennas for mobile terminals.
{"title":"Method of Characteristic Modes Analysis and Manipulation for Antenna Design by Using Generalized Partial Element Equivalent Circuit","authors":"Yuhang Dou;Hao Chen","doi":"10.1109/JMMCT.2023.3242714","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3242714","url":null,"abstract":"A method of analyzing characteristic modes (CMs) of antennas with multiple lumped \u0000<italic>LC</i>\u0000 loads is proposed based on the full-wave generalized partial element equivalent circuit (GPEEC) model. Different with traditional CMs analysis methods, this method can be integrated into an optimization algorithm. With this powerful engine, we can develop a systematic method to manipulate radiation CMs of a mobile terminal while preserving its aesthetic structure features of the industrial design. This method can reveal all possible radiation structure performances as traditional methods and even create new possible radiation modes to improve antenna performance. With the GPEEC model, a comprehensive analysis of antennas can be achieved simultaneously, including but not limited to simulating time-/frequency-domain responses, evaluating radiation efficiency contributed by the self- and mutual radiated power separately, and plotting current and field distribution. Three design examples are demonstrated, including analyzing the working mechanism of the self-curing decoupling technique for mobile terminals from the view of CMs, extending the bandwidth of an antenna in LTE-A low-frequency bands, and creating a pair of MIMO antennas in the low LTE-A bands. These examples are verified theoretically and experimentally, showing the high potential of this method in analyzing and designing antennas for mobile terminals.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-03DOI: 10.1109/JMMCT.2023.3242044
Lihong Feng
Long Short-Term Memory (LSTM) has been more and more used to predict time evolution of dynamics for many problems, especially the fluid dynamics. Usually, it is applied to the latent space after dimension reduction of the full dynamical system by proper orthogonal decomposition (POD), autoencoder (AE) or convolutional autoencoder (CAE). In this work, we propose to directly apply LSTM to the data of the output without dimension reduction for output response prediction. The dimension of the output is usually small, and no dimension reduction is necessary, thus no accuracy loss is caused by dimension reduction. Based on the standard LSTM structure, we propose an LSTM network with modified activation functions which is shown to be much more robust for predicting periodic waveforms. We are especially interested in showing the efficiency of LSTM for predicting the output responses corresponding to time-vary input signals, which is rarely considered in the literature. However, such systems are of great interests in electrical engineering, mechanical engineering, and control engineering, etc. Numerical results for models from circuit simulation, neuron science and a electrochemical reaction have shown the efficiency of LSTM in predicting the dynamics of output responses.
{"title":"Predicting Output Responses of Nonlinear Dynamical Systems With Parametrized Inputs Using LSTM","authors":"Lihong Feng","doi":"10.1109/JMMCT.2023.3242044","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3242044","url":null,"abstract":"Long Short-Term Memory (LSTM) has been more and more used to predict time evolution of dynamics for many problems, especially the fluid dynamics. Usually, it is applied to the latent space after dimension reduction of the full dynamical system by proper orthogonal decomposition (POD), autoencoder (AE) or convolutional autoencoder (CAE). In this work, we propose to directly apply LSTM to the data of the output without dimension reduction for output response prediction. The dimension of the output is usually small, and no dimension reduction is necessary, thus no accuracy loss is caused by dimension reduction. Based on the standard LSTM structure, we propose an LSTM network with modified activation functions which is shown to be much more robust for predicting periodic waveforms. We are especially interested in showing the efficiency of LSTM for predicting the output responses corresponding to time-vary input signals, which is rarely considered in the literature. However, such systems are of great interests in electrical engineering, mechanical engineering, and control engineering, etc. Numerical results for models from circuit simulation, neuron science and a electrochemical reaction have shown the efficiency of LSTM in predicting the dynamics of output responses.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-02DOI: 10.1109/JMMCT.2023.3241633
Lei Zhang;Hui Zeng;Zhenhong Fan;Da-Zhi Ding
This article studies the surface plasmon-enhanced effect of metal nanoparticles (NPs) in thin-film cells by using a semi-classical multiscale quantum-mechanical/electromagnetic (QM/EM) method. The QM/EM method establishes a relationship between classical electromagnetic environment and full quantum-mechanical photovoltaics with quantized vector magnetic potential on the boundary. In our theoretical framework, the EM region is solved by Maxwell equation with method of moments (MoM), and the QM region is solved by density-functional tight-binding (DFTB) theory with the nonequilibrium Green's function. The proposed method has predicted that metal NPs could generate surface plasmon enhancement and substantially improve the photovoltaic performance of thin-film cells. By comparison, we investigated the influences of different NP materials, distributions and drop-casting ratios on the current-voltage characteristics. The simulated results provide a comprehensive understanding of photoelectric interaction, which can be utilized to improve the power conversion efficiency (PCE) of thin-film cells by fast optimization design.
{"title":"Simulation of Thin-Film Cells With a Multiscale Quantum-Mechanical/Electromagnetic Method","authors":"Lei Zhang;Hui Zeng;Zhenhong Fan;Da-Zhi Ding","doi":"10.1109/JMMCT.2023.3241633","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3241633","url":null,"abstract":"This article studies the surface plasmon-enhanced effect of metal nanoparticles (NPs) in thin-film cells by using a semi-classical multiscale quantum-mechanical/electromagnetic (QM/EM) method. The QM/EM method establishes a relationship between classical electromagnetic environment and full quantum-mechanical photovoltaics with quantized vector magnetic potential on the boundary. In our theoretical framework, the EM region is solved by Maxwell equation with method of moments (MoM), and the QM region is solved by density-functional tight-binding (DFTB) theory with the nonequilibrium Green's function. The proposed method has predicted that metal NPs could generate surface plasmon enhancement and substantially improve the photovoltaic performance of thin-film cells. By comparison, we investigated the influences of different NP materials, distributions and drop-casting ratios on the current-voltage characteristics. The simulated results provide a comprehensive understanding of photoelectric interaction, which can be utilized to improve the power conversion efficiency (PCE) of thin-film cells by fast optimization design.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-31DOI: 10.1109/JMMCT.2023.3241190
Kaiser Niknam;Jamesina J. Simpson
A low-leakage total-field/scattered-field plane wave source condition capable of propagating at any incident angle is developed for a newly-developed DGTD-based FVTD method. This constraint-preserving FVTD method provides solutions up to any order of accuracy, preserves the divergence constraints imposed by Gauss’ laws, and may be easily adapted to non-conformal and unstructured meshes. In order to implement the proposed plane wave source condition, several of the steps within the updating loop of the FVTD model, including the Riemann solvers and update equations, must be adapted to ensure the field variables always remain consistent (are consistently designated as either total or scattered fields). The proposed total-field/scattered-field technique is shown to provide numerical leakage errors at the level of machine precision (−300 dB) for second-, third-, and fourth-order constraint-preserving FVTD schemes.
{"title":"A TF/SF Plane Wave Source Condition for the Constraint-Preserving FVTD Method","authors":"Kaiser Niknam;Jamesina J. Simpson","doi":"10.1109/JMMCT.2023.3241190","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3241190","url":null,"abstract":"A low-leakage total-field/scattered-field plane wave source condition capable of propagating at any incident angle is developed for a newly-developed DGTD-based FVTD method. This constraint-preserving FVTD method provides solutions up to any order of accuracy, preserves the divergence constraints imposed by Gauss’ laws, and may be easily adapted to non-conformal and unstructured meshes. In order to implement the proposed plane wave source condition, several of the steps within the updating loop of the FVTD model, including the Riemann solvers and update equations, must be adapted to ensure the field variables always remain consistent (are consistently designated as either total or scattered fields). The proposed total-field/scattered-field technique is shown to provide numerical leakage errors at the level of machine precision (−300 dB) for second-, third-, and fourth-order constraint-preserving FVTD schemes.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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