MSM光电探测器电磁场特性的 TLM方法模拟

介绍了利用传输线矩阵方法模拟和分析金属－半导体－金属光电探测器的指栅电容的频率响应。应用时域电磁场三维TLM方法模拟分析了指栅间距和指栅间的耦合长度与光电探测器截止频率的关系。文中报道了本项研究所开发的三维电磁场时域模拟器TLM Simulator2.0及其功能。数值实验结果说明模拟器对微波结构的电磁场模拟是精确、有效的,具有很好的应用价值。     

数字微波共面带线非线性终端瞬态特性模拟及分析

用FD－TLM法对高速数字微波共面带线端接电阻及非线性终端──半导体二极管时的瞬态响应特性的模拟及分析，并提出一种适用于处理传输线结构终端吸收边界问题的简单、实用的方法。     

一维光子晶体光传输特性的TLM方法分析

传输线矩阵（TLM）方法是一种强有力的时间－空间域内电磁场数值仿真算法。本文在简单介绍TLM方法的原理后，首次用此方法对由两种介电常数不同的材料构成的周期性复层一维光子晶体结构进行了分析。数值模拟结果表明，TLM是分析光子晶体传输特性的有效算法；在可见光波段范围内，光子带隙确定存在，且受电介质材料，空气部分大小等各因素的影响。本文还讨论了在一维结构中引入缺陷时的局域态。     

传输线矩阵(TLM)方法在分析天线阵辐射特性中的应用

本文运用传输线矩阵(Transmission-line Matrix.TLM)方法分析由理想点源构成的直线天线阵的中间区和远区的场特性,并对天线阵的辐射方向图进行了数值计算:本文计算结果与解析分析结果吻合得很好,表明TLM方法是分析天线阵的近区、中间区和远区场的分布特性以及辐射特性的一种较好的方法.     

三维TLM方法在半导体器件的热模拟和热设计中的应用

本文介绍了用三维传输线矩阵法(TLM)分析了不同材料制成的半导体器件的热特性。这种方法能容易地将热特性与温度的关系考虑进去,具有数值稳定性,与其它复杂的几何模型数值技术相比,在计算费用和设备上都有优越性。本文以一个典型的微波功率器件结构的三维热分析为例进行了说明。这个例子说明了在温升受控制的情况下,覆盖金属层的影响和衬底材料的热导率。对瞬态和稳态热计算也作了定量研究。结果表明,TLM法在半导体器件的热分析和热设计中是很有潜力的。     

手征介质填充双平板中导模的反射和透射特性

用多模网络与严格模匹配相结合的方法,对纵向填充一层、两层和多层手征介质的双平板中导模的反射和透射特性进行了分析和求解.分析中在横截面采用等效传输线,在纵向采用多模传输线方法,并且利用结构的对称性使得问题简化.对各种不同情形进行了数值计算,讨论了手征参数和波导结构的尺寸对反射和透射特性的影响.     

部分手征介质填充同轴线的反射和透射特性

用多模网络与严格模匹配相结合的方法 ,对部分手征介质填充同轴线的反射和透射特性进行了分析和求解 .对横截面采用等效径向传输线 ,对纵向采用多模传输线方法 ,并且利用结构的对称性使得问题简化 .讨论了不同情形下手征参数和介电常数对反射和透射特性的影响 .     

电磁场数值模拟TLM算法及其应用

传输线矩阵（TLM）算法是基于Huygens的波传播模型，与计算机结合起来后，成为一种强有力的三维时域电磁场数值仿真算法，在1971年TLM被首次提出以后，便得到不断的改进，从二维到三维，从扩展型结点到凝缩型结点，从时域TLM到频域TLM，而其应用也从最初的处理电磁场问题发展到对微波电路的模拟，高速IC的设计，以及处理光学，机械学，热学和声学问题，本文详细介绍了二维、三维空间的TLM算法，扩展型结点和几种改进的对称凝缩结点，阐述了TLM在各领域的应用，最后还简单介绍了我们完成的工作。     

射频阻抗测量夹具建模技术的研究及应用

分析了阻抗测量夹具中由于阻抗不连续以及信号传输结构变换引起信号的反射,建立PCB板微带传输线、同轴传输线至微带线的转接的模型,最后介绍从测量结果中消除夹具影响的方法.使用自制夹具测量0603封装的贴片器件, 并利用文中介绍的方法进行建模和去嵌入处理,最终获得贴片器件的射频特性;同时可以得到微带线的特性,实际验证了该方法的正确性.     

机箱机柜的电磁兼容性仿真

传输线矩阵（TLM）法是由惠更斯原理离散化得到的,它将求解空间划分为无限多的网格,网格之间由传输线连接,从而将Maxwell方程组中的电场和磁场等效为传输线上的电压和电流进行求解,大幅度减小了求解Maxwell方程所需的时间。     

Application of the TLM method to transient thermal simulation ofmicrowave power transistors

The transmission line matrix (TLM) explicit method of numerical simulation has been used to model the transient thermal properties of various microwave heterojunction bipolar transistor (HBT's) power structures, used in a pulsed mode. Control of the time step during the simulation is of paramount importance and the paper outlines some of the problems encountered using time step control methods currently published and describes an improved algorithm. This improved time step control method has been implemented in a general purpose 3D TLM transient thermal simulator. Some simulation results are described for a variety HBT transistor structures with very different thermal time constants     

Spectral estimation for the transmission line matrix method

The transmission line matrix (TLM) method for microwave circuit analysis calculates the time-domain variation of the electromagnetic fields in response to an arbitrarily chosen excitation. Spectral estimation for the TLM method by use of the discrete fourier transform and fast Fourier transform is reviewed. Error bounds are given and checked by means of a numerical example. A spectral estimation method based on Prony's method for use with TLM is presented. A numerical example shows that the method allows an order of magnitude reduction in the number of iterations in the TLM method for equal accuracy     

Absorbing and connecting boundary conditions for the TLM method

Absorbing and connecting boundary conditions are implemented for the transmission-line matrix (TLM) method. The approach is based on an equivalence previously established between the finite-difference-time-domain (FD-TD) method and the TLM method. Boundary conditions presently used for the FD-TD algorithm can be transformed into conditions that can be interfaced with two-and three-dimensional (2D and 3D) TLM schemes. Additional conditions are introduced for 3D-TLM symmetrical condensed node simulations to suppress instabilities caused by spurious modes, inherent to the model, and which are amplified by absorbing boundaries. Numerical results and the comparison with other methods show the good performance of the proposed algorithms     

The frequency-domain transmission line matrix method-a new concept

A frequency-domain transmission line matrix (TLM) method for the frequency-selective S-matrix computation of 3D waveguide discontinuities is presented. It combines the flexibility of the conventional TLM method with the computational efficiency of frequency-domain methods. The basis for this technique is the excitation of an impulse train of sinusoidally modulated magnitude, which retains the form of an impulse while its envelope contains the information of the structure at the modulation frequency. Utilizing the diakoptics technique in conjunction with the concept of the intrinsic scattering matrix, the original electromagnetic field problem is simplified to a matrix algebra problem. A variety of structures have been analyzed in order to check the accuracy of the approach, and excellent agreement has been observed in all cases. S-parameters for CPW air-bridges including finite thickness and conductivity of the metallizations are computed. The effect of superconducting air-bridges is analyzed     

用TLM法模拟二维三维电磁散射近场和远场

数值模拟二维等腰直角三角形导电柱体和三维方形导电柱体对高斯脉冲平面波的电磁散射近场和远场分布。数值结果表明在三角柱体的电磁散射近场中镜面反射并不明显,但在远场却非常明显并且成为最主要的散射方向。三维电磁散射的数值结果表明,二次辐射是电磁散射的主要机理,并且在多个导体目标情况下,各自的散射场将互相干涉形成总的散射场。     

线天线及天线阵的时域传输线矩阵法分析

本文针对线天线及天线阵的频域分析方法的缺点，首次将时域传输线矩阵法应用到这一领域，应用时域ＴＬＭ法时，只需经过一次运逄就可以得到天线及天线阵各个区域的场特性，本文计算方法及数值结果表明，运用时域ＴＬＭ法可以对各种大型天线阵进行有效的分析，便于工程应用。     

Lossy dielectric and thin lossy film models for 3D steady state TLM

The 3D steady state TLM technique (SS-TLM) is extended to provide TLM models for lossy materials and thin lossy films in the frequency domain. The models are evaluated by comparing with time domain TLM (TD-TLM) and analytic solutions.<>     

A two-dimensional transmission line matrix microwave fieldsimulator using new concepts and procedures

A two-dimensional field simulator for microwave circuit modeling is described. It incorporates a number of recently developed concepts and advanced transmission line matrix (TLM) procedures. In particular, a discrete Green's function concept based on P.B. John's and K. Akhlarzad's time-domain diakoptics is realized, providing a high level of processing power through modularization of large structures at the field level, simulation of wideband matched loads or absorbing walls, modeling of frequency-dispersive boundaries in the time domain, and large-scale numerical preprocessing of passive structures. Nonlinear field modeling concepts are also implemented in the TLM field simulator. It can analyze two-dimensional circuits of arbitrary geometry containing both linear and nonlinear media. The circuit topology is input graphically. Both time-domain and frequency-domain responses can be computed and displayed. The capabilities and limitations of the simulator are discussed, and several microstrip and waveguide components are modeled to demonstrate its important features