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Thompson-fdtd method for dielectric objects

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2001年第5期28卷 351-354页

作者： Liao, C Meng, L SW Jiaotong Univ Inst Electromagnet Chengdu 610031 Peoples R China Univ Elect Sci & Technol China High Energy Elect Inst Chengdu 610031 Peoples R China

The Thompson-fdtd method, which combines the differential-Thompson transformation involved in hydromechanics with the finite-difference time-domain (fdtd) technique, is introduced to simulate the electromagnetic scattering properties of arbitrarily shaped dielectric media in this paper. This method has at least two obvious advantages. First, it is able to transform an arbitrarily shaped body into a regular structure which accurately matches the boundary conditions;second, the mesh arrangement can be adjusted according to the scatterer's shape to achieve better numerical accuracy. (C ) 2001 John Wiley & Sons, Inc.

关键词： EM scattering numerical simulation fdtd algorithm Thompson transformation

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Relativistic fdtd Analysis of Far-Field Scattering of a High-Speed Moving Object

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2015年 14卷 879-882页

作者： Kuang, Lei Xu, Feng Zhu, Shouzheng Gao, Jianjun Zheng, Zhengqi E China Normal Univ Sch Informat Sci & Technol Shanghai 200241 Peoples R China Fudan Univ Key Lab Informat Sci Electromagnet Waves MoE Shanghai 200433 Peoples R China

Far-field scatterings of uniformly moving conducting and dielectric objects are analyzed in this letter. Using the Lorentz transformation, the scattering problem of a high-speed moving object in the laboratory frame, which is stationary with respect to the free space, is transformed to that of a motionless object in the rest frame that moves with the moving object. Then the near-zone scattered fields are solved by the Finite Difference Time Domain (fdtd) algorithm. Applying near-to-far field transformation, farzone scattered fields are acquired in the rest frame. Subsequently, the scattered fields are transformed back to the laboratory frame. Our approach is validated against previously published results for the case of a uniformly moving two-dimensional object. Numerical examples show that the effects of the motion on the bistatic radar cross sections (RCS) and Doppler are non-negligible for high-speed objects.

关键词： Electromagnetic scattering fdtd algorithm lorentz transformation moving object

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Computation of the optical trapping force using an fdtd based technique

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OPTICS EXPRESS 2005年第10期13卷 3707-3718页

作者： Gauthier, RC Carleton Univ Dept Elect Ottawa ON K1S 5B6 Canada

The computation details related to computing the optical radiation pressure force on various objects using a 2-D grid fdtd algorithm are presented. The technique is based on propagating the electric and magnetic fields through the grid and determining the changes in the optical energy flow with and without the trap object(s) in the system. Traces displayed indicate that the optical forces and fdtd predicted object behavior are in agreement with published experiments and also determined through other computation techniques. We show computation results for a high and low dielectric disc and thin walled shell. The fdtd technique for computing the light-particle force interaction may be employed in all regimes relating particle dimensions to source wavelength. The algorithm presented here can be easily extended to 3-D and include torque computation algorithms, thus providing a highly flexible and universally useable computation engine. (C) 2005 Optical Society of America.

关键词： .various optically propagating optical trapping disc laser beam Ashkin low dielectric radiation pressure fdtd algorithm energy flow computation results fdtd technique light-particle

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fdtd METHOD INVESTIGATION ON THE POLARI-METRIC SCATTERING FROM 2-D ROUGH SURFACE

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PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER 2010年 101卷 173-188页

作者： Li, J. Guo, L. -X. Zeng, H. Xidian Univ Sch Sci Xian Shaanxi Peoples R China

A polarimetric scattering from two-dimensional (2-D) rough surface is presented by the finite-difference time-domain (fdtd) algorithm. The fdtd calculations with sinusoidal and pulsed plane wave excitations are performed. As the sinusoidal fdtd is concerned, it is convenient to obtain the scattered angular distribution of normalized radar cross section (NRCS) from rough surface for a single frequency. And the advantage of pulsed fdtd is to calculate the frequency distribution of NRCS from rough surface in a scattered direction of interest. A single frequency scattering from rough surface by sinusoidal fdtd is validated by the result of Kirchhoff Approximation (KA). And the frequency response of rough surface by pulsed fdtd is verified by that of sinusoidal fdtd, which requires an individual fdtd run for every frequency. To save computation time, the MPI-based parallel fdtd method is adopted. And the computation time of parallel fdtd algorithm is dramatically reduced compared to a single-process implementation. Finally, the polarimetric scattering of rough surface with the sinusoidal and pulsed fdtd illumination are presented and analyzed for different polarizations.

关键词： .difierent fdtd algorithm sinusoidal fdtd pulsed fdtd

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A novel fdtd approach featuring two-level parallelization on PC cluster

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PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER 2008年 80卷 393-408页

作者： Liu, Y. Liang, Z. Yang, Z. Q. Univ Elect Sci & Technol China Coll Phys Elect Chengdu 610054 Peoples R China

To improve the parallel efficiency in the case of the finegrained fdtd computing on PC cluster, the concept of "two level parallelization on PC cluster" is presented, and a high performance MPI-OpenMP hybrid fdtd algorithm is developed. In the hybrid algorithm, MPI is used in conjunction with OpenMP multithreading to achieve two level parallelism of the data and tasks at the basis of the domain decomposition fdtd method. Besides, to enhance the flexibility of the parallel fdtd, the interpolation between subspaces is also discussed. The simulation example of a printed antenna for automobile is given. Computations are performed for different numbers of PCs and contrasted with two conventional parallel fdtd algorithms on PC cluster. The results show that with the decrease of the computational granularity on each computer, the novel algorithm is more efficient, and moreover, it can also lessen the influence of the sub-domains virtual topology on the parallel fdtd performance.

关键词： .subspaces virtual topology MPI-OpenMP hybrid algorithm multithreading domain decomposition fdtd algorithm PC CLUSTER level parallelization data and tasks

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Characteristics of Mesh Wave Impedance in fdtd Non-Uniform Mesh

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Journal of Beijing Institute of Technology 2005年第2期14卷 154-157页

作者：任武刘波高本庆 School of Information Science and Technology Beijing Institute of Technology Beijing100081 China School

In order to increase the evaluating precision of mesh reflection wave, the mesh wave impedance (MWI) is extended to the non-uniform mesh in 1-D and 2-D cases for the first time on the basis of the Yee's positional relation for electromagnetic field components. Lots of characteristics are obtained for different mesh sizes and frequencies. Then the reflection coefficient caused by the non-uniform mesh can be calculated according to the theory of equivalent transmission line. By comparing it with that calculated by MWI in the uniform mesh, it is found that the evaluating error can be largely reduced and is in good agreement with that directly computed by fdtd method. And this extension of MWI can be used in the error analysis of complex mesh.

关键词： mesh wave impedance (MWI) non-uniform mesh fdtd algorithm reflection coefficient

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Research on Non-uniform Nested Grid fdtd Method Based on Ionospheric Zakharov Model 12

Research on Non-uniform Nested Grid FDTD Method Based on Ion...

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12th International Symposium on Antennas, Propagation and Electromagnetic Theory (ISAPE)

作者： Song, Jingjun Shi, Lijuan Zhang, Shitian Li, Qinliang Yang, Lixia Jiangsu Univ Sch Comp Sci & Commun Engn Zhenjiang Peoples R China China Res Inst Radiowave Propagat Natl Key Lab Electromagnet Environm Xinxiang Peoples R China

ISBN: (纸本)9781538673027

This paper, based on plasma generalized Zakharov model in ionosphere, studies the non-uniform nested grid in fdtd algorithm under plasma background. It is used to improve the fdtd algorithm for studying the nonlinear process of the ionospheric Langmuir disturbance. A non-uniform nested grid method which can reduce the computational complexity of explicit fdtd algorithm while guaranteeing the computational accuracy is studied. A non-uniform nested grid fdtd method for calculating electromagnetic problems involving different orders of magnitude is proposed. Finally, the correctness and superiority of the non-uniform nested grid are verified by simulating the electromagnetic field distribution and propagation characteristics of the ionospheric Langmuir disturbance.

关键词： fdtd algorithm non-uniform nested grid ionosphere

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A strongly well-posed PML with unsplit-field formulations in cylindrical and spherical coordinates

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JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS 2005年第13期19卷 1761-1776页

作者： Shi, Y Liang, CH Xidian Univ Sch Elect Engn Xian 710071 Peoples R China

A simple and systematic derivation of strongly well-posed perfectly matched layer (PML) in cylindrical and spherical coordinates is presented. The unsplit-field PML formulations are expressed in terms of the complex coordinate stretching approach which was originally proposed for split-field PML. The well-posed PML formulations include the symmetric hyperbolic system besides some lower order terms which do not affect the well-posedness of the system. Numerical simulations validate the accuracy and efficiency of the unsplit-field PML.

关键词： PERFECTLY MATCHED LAYER TIME-DOMAIN METHOD fdtd algorithm PSTD algorithm LOSSY MEDIA SIMULATIONS ABSORPTION SCATTERING EQUATIONS WAVES

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An Array of SiO₂ Helix Structure for Terahertz Filter

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JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE 2010年第10期7卷 1965-1967页

作者： Yi Lingjie Zhou Xiuli Shi Zhenkui Fu Yongqi Wang Shiyong Univ Elect Sci & Technol China Sch Phys Elect Chengdu 610054 Peoples R China

A terahertz (THz) reflection-type convex filter with SiO2 helix structure is presented here. The reflection filter was designed at 2.84 THz with a full width at half-maximum (FWHM) of 0.71 THz. Finite Difference Time Domain (fdtd) method was used to study the transmission properties theoretically. The simulation results show that the position and the line shape of the resonant dip remain unchanged for a broad increasing polarization angle from 0 degrees to 50 degrees. It demonstrates that this type of filter have ultrahigh immunity to polarization.

关键词： Terahertz Filter fdtd algorithm Helix Structure

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Simple pictograph for displaying complex field data in TEM cell tissue sample

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ELECTRONICS LETTERS 2002年第8期38卷 359-360页

作者： Lim, HB Cook, GG Barker, AT Coulton, LA Univ Sheffield Dept Elect & Elect Engn Radar & Commun Grp Sheffield S1 3JD S Yorkshire England Royal Hallamshire Hosp Dept Med Phys & Clin Engn Sheffield S10 2JF S Yorkshire England Univ Sheffield No Gen Hosp Div Clin Sci Sheffield S5 7AU S Yorkshire England

A simple diagram is described Cor displaying complex field data calculated using an original finite-difference time-domain algorithm. This polar plot is used to display field properties within a culture medium placed in a transverse electro-magnetic (TEM) cell, and shows the presence of an elliptically polarised exposure field with reactive phasing, arising from a plane wave incident field. The pictograph aids in comprehending this field behaviour, which may be relevant to any biological effects.

关键词： complex field data display finite-difference time-domain algorithm fdtd algorithm biological effects of fields diagrams culture medium elliptically polarised exposure field reactive phasing electromagnetic fields biological tissue samples finite difference time-domain analysis biological effects Numerical approximation and analysis dosimetry experiments field properties polar plot Radiation protection and dosimetry Radiation dosimetry in medical physics Biological effects of radiations transverse electromagnetic cell Other numerical methods plane wave incident field biological techniques dosimetry pictograph Biophysical instrumentation and techniques

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