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Modal analysis of nonuniformly dielectric waveguide using semivectorially compact finite-difference time-domain method

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INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES 2005年第5期26卷 725-738页

作者： Zheng, HX Yu, DY Tianjin Univ Coll Precis Instrument & Optoelect Engn Tianjin 300072 Peoples R China

A compact two-dimensional finite-difference time-domain method is developed for the modal analysis of nonuniform dielectric waveguides. The unsplit-field perfectly-matched-layer absorbing boundary condition has also been extended to this approach. The proposed method approximates the maxwell equations by using the semivectorial wave equations, and the dominant electric fields are solved for two perpendicular polarizations. By introducing the new techniques, complex variables can be avoided in the calculations. At the same time, the number of variables is minimized in the computation domain. Through that, approximately half of the computation effort can be saved without accuracy loss. Numerical examples are given to substantiate the theory. Excellent accuracy has been obtained for the entire frequency spectrum, even near the cutoff region.

关键词： absorbing boundary condition below cutoff modes finite-difference time-domain method infrared waveguides nonuniformly dielectric waveguides perfectly matched layer semivectorially compact wave equations

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Improved Performance of FDTD Computation Using a Thread Block Constructed as a Two-Dimensional Array with CUDA

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APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL 2010年第12期25卷 1061-1069页

作者： Takada, Naoki Shimobaba, Tomoyoshi Masuda, Nobuyuki Ito, Tomoyoshi Shohoku Coll Sony Inst Higher Educ Dept Informat & Media Technol Kanagawa 2438501 Japan Chiba Univ Grad Sch Engn Inage Ku Chiba 2638522 Japan

In a previous study, the authors proposed an fmite-difference time-domain (FDTD) implementation for a compute unified device architecture (CUDA) compatible graphics processing unit (GPU) using a thread block constructed as a two-dimensional (2-D) array. However, it was found that the larger the computational domain of the 2-D FDTD simulation using the GPU, the slower the computational speed. In the present paper, the authors investigated the computational performance with respect to the size of a thread block constructed as a 2-D array, and improved the performance of the implementation. Finally, regardless of the size of computational domain, the computational speed using a single GPU (NVIDIA GeForce GTX 280) achieved approximately 30.0 Gflops, which was approximately 20 times faster than that of a single core of a central processing unit (Intel 3.0-GHz Core 2 Duo). The improved performance was approximately 65% of the theoretical peak performance (47.23 Gflops) obtained by the theoretical memory bandwidth (141.7 GB/s).

关键词： finite-difference time-domain method GPU computing graphics processing unit high-performance computing

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Simulations of light scattering from a biconcave red blood cell using the finite-difference time-domain method

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JOURNAL OF BIOMEDICAL OPTICS 2005年第2期10卷 024022页

作者： Lu, JQ Yang, P Hu, XH E Carolina Univ Dept Phys Greenville NC 27858 USA Texas A&M Univ Dept Atmospher Sci College Stn TX USA

Numerical simulations of light scattering by a biconcave shaped human red blood cell (RBC) are carried out using the finite-difference time-domain (FDTD) method. A previously developed FDTD code for the study of light scattering by ice crystals is modified for the current purpose and it is validated against Mie theory using a spherically shaped RBC. Numerical results for the angular distributions of the Mueller scattering matrix elements of an RBC and their dependence on shape, orientation, and wavelength are presented. Also calculated are the scattering and absorption efficiencies. The implication of these results on the possibility of probing RBC shape changes is discussed. (c) 2005 Society of Photo-Optical instrumentation Engineers.

关键词： red blood cell cell scattering finite-difference time-domain method Mueller scattering matrix

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Analysis of femtosecond optical pulse propagation in one-dimensional nonlinear photonic crystals using finite-difference time-domain method

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OPTIK 2005年第10期116卷 486-492页

作者： Shokooh-Saremi, M Mirsalehi, MM Ferdowsi Univ Mashhad Fac Engn Dept Elect Engn Mashhad 1111 Iran Univ Sydney Sch Phys CUDOS Sydney NSW 2006 Australia

In this paper, we have used the finite-difference time-domain (FDTD) method to analyze the optical pulse propagation in a nonlinear, one-dimensional photonic crystal (1DPC). Hyperbolic secant pulses with various carrier wavelengths are utilized in this study. In a nonlinear regime, a 1DPC introduces a photonic band-gap whose central wavelength and width depend on the input pulse intensity. In the present work, three different cases are considered. These correspond to the carrier wavelengths of the incident pulses being out of, near to, and partially in the band-gap. For each case, the effect of nonlinearity on pulse propagation is investigated. Also, we have analyzed the two-frequency regime, in which each of the two pulses has a different carrier frequency (wavelength). This kind of study can be done directly with FDTD without any further computational burden but it is somewhat complicated using nonlinear coupled-mode equations (NLCME) and nonlinear Schrodinger equation (NLSE), which require separate treatments for each carrier wavelength. (c) 2005 Elsevier GmbH. All rights reserved.

关键词： nonlinear photonic crystals optical pulse propagation finite-difference time-domain method

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Calculation of diffraction characteristics of subwavelength conducting gratings using a high accuracy nonstandard finite-difference time-domain method

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OPTICAL REVIEW 2005年第4期12卷 274-280页

作者： Banerjee, S Cole, JB Yatagai, T Univ Tsukuba Inst Appl Phys Tsukuba Ibaraki 3058573 Japan Univ Tsukuba Dept Syst & Informat Engn Tsukuba Ibaraki 3058573 Japan

Gratings with subwavelength groove depth and period are frequently used in optics for various purposes. The polarization dependent diffraction characteristics of subwavelength (high frequency) gratings can only be calculated by solving Maxwell's equations of electromagnetism. In this paper, we calculate the classical diffraction characteristics of subwavelength conducting gratings numerically, using a new high accuracy version of nonstandard finite-difference time-domain (NS-FDTD) algorithm. For the purpose of analysis, we employ a gold sinusoidal grating with light incident at a large angle. We have compared high accuracy NS-FDTD simulation results with those obtained from standard finite-difference time-domain (S-FDTD), and the finite element method (FEM) simulations. (c) 2005 The Optical Society of Japan.

关键词： grating diffraction subwavelength diffractive optical elements conducting gratings microoptics electromagnetic theory finite-difference time-domain method

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finite-difference time-domain model for the feeding gap of coaxial probe driven antennas

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IET MICROWAVES ANTENNAS & PROPAGATION 2009年第3期3卷 501-506页

作者： Hyun, S. -Y. Kim, S. -Y. Kim, Y. -S. Korea Inst Sci & Technol Imaging Media Res Ctr Seoul 136791 South Korea Korea Univ Dept Radio Sci & Engn Seoul 136701 South Korea

In the finite-difference time-domain (FDTD) method, a simple and realistic feed model for coaxial probe driven antennas is proposed here. The feed zone of the antenna may be considered as an equivalent source in view of the antenna theory and a load port in view of the transmission line theory. The proposed feed model is constructed by combining the infinitesimal-gap source condition of the antenna and the equivalent load condition of the feed line. It leads to perform no additional FDTD cell modelling of the line. The transient reflected voltage and the input impedance of cylindrical monopole antennas fed by coaxial lines are calculated numerically and then compared with the accurate measurement and a full fine-grid. The FDTD results of the proposed model have a good agreement with the measured data and the fine-grid results.

关键词： antenna feed zone Other numerical methods cylindrical monopole antennas infinitesimal-gap source condition Antenna accessories Antenna theory input impedance transient reflected voltage antenna theory Transmission line theory equivalent load condition monopole antennas finite difference time-domain analysis coaxial probe driven antennas Single antennas coaxial cables transmission line theory antenna feeds finite-difference time-domain method coaxial lines

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Electromagnetic method for sample-induced resistance calculation of magnetic resonance coils

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INTERNATIONAL JOURNAL OF BIOMEDICAL ENGINEERING AND TECHNOLOGY 2010年第1期4卷 18-28页

作者： Giovannetti, Giulio Viti, Vittorio Hartwig, Valentina Liu, Yongjun Yu, Wenhua Mittra, Raj Landini, Luigi Benassi, Antonio Natl Council Res Inst Clin Physiol Via Moruzzi 1 I-56124 Pisa Italy Esaote Biomed I-16153 Genoa Italy Penn State Univ Elect Engn East 319 University Pk PA 16802 USA Univ Pisa Dept Informat Engn I-56122 Pisa Italy

Signal-to-Noise Ratio (SNR) calculation in Magnetic Resonance (MR) experiments requires the knowledge of biological sample-induced resistance value. Many authors studied sample-coil interaction by using quasi-static approach, with very simple coil and sample geometries;such method fails at high-field Magnetic Resonance Imaging (MRI). In this paper, we propose a theoretical algorithm for sample-induced resistance estimation, which uses a numerical solver based on finite-difference time-domain (FDTD) method for simulating MR systems. Comparison with experimental data demonstrated the great accuracy of the developed algorithm. The proposed method can be used as a tool to estimate sample-induced resistance values for more complex geometries.

关键词： SNR signal-to-noise ratio sample-induced resistance electromagnetic simulator finite-difference time-domain method

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Rigorous electromagnetic analysis of Talbot effect with the finite-difference time-domain method

Rigorous electromagnetic analysis of Talbot effect with the ...

引用

Conference on Optical Design and Testing II

作者： Lu, YQ Zhou, CH Chinese Acad Sci Shanghai Inst Opt & Fine Mech Informat Opt Lab Shanghai 201800 Peoples R China

ISBN: (纸本)0819455938

We present the electromagnetic analysis of Talbot effect with the finite-difference time-domain (FDTD) method. To our knowledge, it is the first time that FDTD method is applied to analyze the performance of a Talbot illuminator. Furthermore, self-imaging performances of a grating with different flaws are analyzed. The FDTD method can be applied to analyze this kind of diffraction. Of course it also can be analyzed with the Fourier transform method. But for this non-period grating, it will be more complex. In addition, the grating employed here is a high-density grating. The Fourier transform method is not rigorous enough. For these reasons, the FDTD method can show the exact near-field distribution of different flaws in a high-density grating, which is impossible to attain with the conventional Fourier transform method.

关键词： Talbot array illuminators finite-difference time-domain method

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Optimizing the spectral efficiency of photonic quantum well structures

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OPTIK 2009年第1期120卷 35-39页

作者： Liu, Jing Sun, Junqiang Huang, Chongqing Hu, Wenjing Huang, Dexiu Huazhong Univ Sci & Technol Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China Hunan Inst Sci & Technol Dept Phys Yueyang 414006 Hunan Peoples R China

One can construct photonic single quantum well structures by sandwiching a homogeneous medium slab as a defect between two symmetrical photonic crystals (PCs). It is shown that the number of observed resonant peaks increases with increasing slab thickness. It is found that while the slab is composed of alternatively stacked step-index films, the frequencies of these resonant peaks can be adjusted finely by changing the film thickness properly. In this case, the frequency and frequency interval of confined states can be tuned accurately, and the spectral efficiency can be greatly enhanced without increasing the volume of optical devices. Numerical simulation is based on the finite-difference time-domain (FDTD) method. (C) 2007 Elsevier GmbH. All rights reserved.

关键词： Spectral efficiency Confined states finite-difference time-domain method Photonic quantum well

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A Study of Properties of the Photonic Band Gap of Unmagnetized Plasma Photonic Crystal

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Plasma Science and Technology 2009年第1期11卷 14-17页

作者：刘崧钟双英刘三秋 School of Sciences Nanchang University

In this study, the propagation of electromagnetic waves in one-dimensional plasma photonic crystals （PPCs）, namely, superlattice structures consisting alternately of a homogeneous unmagnetized plasma and dielectric material, is simulated numerically using the finite-difference time-domain （FDTD） algorithm. A perfectly matched layer （PML） absorbing technique is used in this simulation. The reflection and transmission coefficients of electromagnetic （EM） waves through PPCs are calculated. The characteristics of the photonic band gap （PBG） are discussed in terms of plasma density, dielectric constant ratios, number of periods, and introduced layer defect. These may provide some useful information for designing plasma photonic crystal devices.

关键词： plasma photonic crystal finite-difference time-domain method photonic band gap reflection and transmission coefficients

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