检索结果-内蒙古大学图书馆

Comparison study of the PSTD and FDTD methods for scattering analysis

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2000年第3期25卷 220-226页

作者： Li, QL Chen, YC Ge, DB Hong Kong Polytech Univ Dept Elect & Informat Engn Hong Kong Hong Kong Peoples R China Xidian Univ Dept Phys Xian 710071 Peoples R China

This paper makes a comparison study by using both the pseudospectral time-domain (PSTD) and finite-difference time-domain (FDTD) methods for a two-dimensional (2-D) scattering analysis. The time-domain incident plane-wave pulse used in the PSTD technique is herewith simulated with an initial-condition excitation technique to eliminate the unwanted Gibbs phenomenon. The pure scattered-field formulation is utilized to surmount the difficulty of generation of the incident field, and a PSTD near-to-far-zone field transform is developed for the analysis of the scattering width (SW) of targets. It is found that the PSTD computed results agree well with those derived from the FDTD method, while the PSTD requires much less computational space and CPU time. (C) 2000 John Wiley & Sons, Inc.

关键词： pseudospectral time-domain algorithm finite-difference time-domain method scattering analysis

来源：评论

学校读者我要写书评

暂无评论

Simulation of human interaction with mobile telephones using hybrid techniques over coupled domains

引用

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2000年第11期48卷 2014-2021页

作者： Mangoud, MA Abd-Alhameed, RA Excell, PS Univ Bradford Ctr Telecommun Res Bradford BD7 1DP W Yorkshire England

An approach to hybridization of the method of moments and the finite-difference time-domain method is investigated in this paper. This hybrid method is capable of analyzing a system of multiple discrete regions by employing the principle of equivalent sources to excite their coupling surfaces. The case of multiple sources in the presence of scattering objects is discussed. To develop the approach and test its validity, some examples are given using the same numerical method in multiple regions: the results compare well with other available data, The theory of the heterogeneous hybrid method is then developed and validated. It is shown that this technique has the great advantage of accurately modeling complex and arbitrarily oriented mobile telephone handset antennas in the proximity of a detailed voxel representation of the human head, as required for safety and radiation pattern assessments.

关键词： bioelectromagnetics computational electromagnetics finite-difference time-domain method hybrid methods method of moments mobile telephones safety

来源：评论

学校读者我要写书评

暂无评论

Amplitude degradation of time-reversed pulses in nonlinear absorbing thermoviscous fluids

引用

ULTRASONICS 2000年第9期38卷 885-889页

作者： Hallaj, IM Cleveland, RO Barbone, PE Kargl, SG Roy, RA Harvard Univ Brigham & Womens Hosp Sch Med Radiol MRI Boston MA 02115 USA Boston Univ Dept Aerosp & Mech Engn Boston MA 02215 USA Univ Washington Appl Phys Lab Seattle WA 98105 USA

The linear wave equation in a lossless medium is time reversible, i.e., every solution p(x, t) has a temporal mirror solution p(x, -t). Analysis shows that time reversal also holds for the lossless nonlinear wave equation. In both cases, time-reversal invariance is violated when losses are present. For nonlinear propagation loses cannot normally be ignored;they are necessary to prevent the occurrence of multivalued waveforms. Further analysis of the nonlinear wave equation shows that amplification of a time-reversed pulse at the array elements also leads to a violation of time reversal even for lossless nonlinear acoustics. Numerical simulations are used to illustrate the effect of nonlinearity on the ability of a time-reversal system to effectively focus on a target in an absorbing fluid medium. We consider both the amplitude and arrival time of retrodirected pulses. The numerical results confirm that both shock generation (with the accompanying absorption) and amplification at the array, adversely affect the ability of a time-reversal system to form strong retrodirective sound fields. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： time reversal nonlinear propagation finite-difference time-domain method

来源：评论

学校读者我要写书评

暂无评论

Characteristics of eccentric coaxial line using conformal mapping and finite-difference time-domain method

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 1997年第4期16卷 249-252页

作者： Zhou, XJ Yu, ZY Lin, WG University of Electronic Science and Technology of China Chengdu 610054 China

This paper presents a general group of formulas by a combination of conformal mapping and 2-D FDTD (CF-FDTD). By this new method, the cutoff wavenumbers and dispersive characteristics of higher order TE modes in an ec... 详细信息

关键词： finite-difference time-domain method coaxial line conformal mapping

来源：评论

学校读者我要写书评

暂无评论

Phased array antenna analysis using time delay beam steering and hybrid FDTD method

引用

ELECTRONICS LETTERS 2000年第2期36卷 108-110页

作者： Parfitt, AJ Bird, TS CSIRO Epping NSW 1710 Australia

A phased array analysis is presented where the coupling between antenna elements and the beam steering is computed in the time domain using a hybrid finite-difference time-domain (FDTD) and Kirchhoff transform method. The coupled currents are combined with the appropriate time delays to give the total element current, which is then used in conjunction with the voltage excitation to produce the driving point admittance as a function of frequency for a given beam direction.

关键词： coupled currents time delay beam steering Kirchhoff transform method driving point admittance time domain computation Antenna theory Other numerical methods finite difference time-domain analysis voltage excitation Antenna arrays antenna phased arrays electric admittance phased array antenna analysis hybrid FDTD method delays antenna theory finite-difference time-domain method

来源：评论

学校读者我要写书评

暂无评论

Novel meandered planar inverted-F antenna for triple-frequency operation

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2000年第1期27卷 58-60页

作者： Dou, WP Chia, YWM Ctr Wireless Commun Singapore 117674 Singapore

A novel meandered planar inverted-F antenna with a single feed is presented for triple-frequency operation. Using two shorting strips, good impedance matching is achieved in three bands. This compact low-profile design shows characteristics of near-omnidirectional radiation patterns with minimal hand effects, which is preferable for application in wireless communications. (C) 2000 John Wiley & Sons, Inc.

关键词： planar inverted-F antenna meandered antenna triple-frequency operation finite-difference time-domain method

来源：评论

学校读者我要写书评

暂无评论

Effects of current source models on numerical performances in FDTD simulations

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2000年第1期27卷 4-7页

作者： Yuan, WL Liang, CH Shi, XW Wang, BK Inst High Performance Comp EMC Div Singapore 118261 Singapore Xidian Univ Dept Microwave Telecommun Engn Xian 710071 Peoples R China

A source model can influence FDTD numerical performance although it may be a fictitious source in some FDTD computations. The current source models for FDTD excitation, both resistance free and resistive, and presented, respectively, which are directly derived from Maxwell's equations. The former is simple in implementation and high in computational accuracy by comparison with a voltage source excitation, and the latter possesses stability,and can reduce the computation time as the resistance is properly chosen which means it an be optimized in terms of its internal resistance. (C) 2000 John Wiley & Sons, Inc.

关键词： finite-difference time-domain method current source model numerical performance

来源：评论

学校读者我要写书评

暂无评论

Theory and experiment on microstrip patch antennas with shorting walls

引用

IEE PROCEEDINGS-MICROWAVES ANTENNAS AND PROPAGATION 2000年第6期147卷 521-525页

作者： Lee, KF Guo, YX Hawkins, JA Chair, R Luk, KM Univ Mississippi Sch Engn University MS 38677 USA City Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China Univ Missouri Dept Elect Engn Columbia MO USA

Experimental and calculated results based on the finite-difference time-domain method are presented on the impedance and radiation characteristics of the classic shorted quarterwave patch. It is found that, for foam substrates with relative permittivity close to unity, the bandwidths of the quarterwave patches are significantly larger than the halfwave patches. On the other hand, for microwave substrates with relative permittivites equal to 2.32 and 4.0. the bandwidths of quarterwave patches are less than those of halfwave patches, owing to the excitation of surface waves. The maximum gain in the case of foam substrate is in the range of 2-3.5dBi, occurring 0-45 degrees from broadside, depending on the substrate thickness. The use of a partial short, while reducing the resonant frequency, also decreases the bandwidth. The paper also describes the application of the shorting-wall principle to realise a compact wideband L-probe patch antenna.

关键词： finite difference time-domain analysis compact wideband L-probe patch antenna FDTD method 2 to 3.5 dB relative permittivity surface waves excitation Single antennas microstrip antennas microwave substrates antenna radiation patterns finite-difference time-domain method microstrip patch antennas shorted quarterwave patch electric impedance partial short bandwidth shorting walls radiation characteristics foam substrates halfwave patches impedance characteristics Other numerical methods

来源：评论

学校读者我要写书评

暂无评论

A new subgridding method for the finite-difference time-domain (FDTD) algorithm

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 1999年第5期21卷 330-333页

作者： Yu, WH Mittra, R Penn State Univ Electromagnet Commun Res Lab University Pk PA 16801 USA

In this paper, the authors present a general subgridding scheme for enhancing the finite-difference time-domain (FDTD) algorithm. It is different from the conventional approaches in that it does not employ weighed averages of the electric or magnetic fields in the transition region from the coarse to the fine region, but instead employs a novel procedure for transferring the information between the two regions. We illustrate the application of the subgridding algorithm by considering a refinement factor of 5, and provide validation of the results obtained. (C) 1999 John Wiley & Sons, Inc.

关键词： finite-difference time-domain method subgridding scheme numerical method

来源：评论

学校读者我要写书评

暂无评论

Development of three-dimensional monolithic microwave integrated circuit components

Development of three-dimensional monolithic microwave integr...

引用

Conference on Terahertz and Gigahertz Electronics and Photonics II

作者： Hwu, RJ Ren, J Univ Utah Dept Elect Engn Salt Lake City UT 84112 USA

ISBN: (纸本)0819437565

FDTD applications in 3D monolithic microwave integrated circuit (MMIC) design are introduced in this paper. The source implementation for active device modeling, device-grid characterization, and novel spiral component simulations are presented. Our research in this area have shown that FDTD is a very effective tool for the design of 3D MMICs.

关键词： 3D modeling finite-difference time-domain method Transformers Inductance Field effect transistors Integrated circuits Microwave radiation Instrument modeling Oscillators Analytical research

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：