用NILT导出的传输线瞬态分析模型

K Singhal与J Vlach的NILT(数值Laplace反变换) 技术是端接线性负载传输线分析的一种有效方法.本文利用这一NILT技术,导出了传输线的时域离散模型,由此可进行端接任意负载传输线的瞬态分析.这一模型毋须象通常的频域方法那样对传输线作有理逼近,因而不存在由此带来的数值问题,而计算量与它们相当.文中分别给出了均匀与非均匀传输线的处理,并用实例作了验证.     

宽带传输线变压器的分析与设计

研究了变换比为1：n^2(n为整数）的宽频带传输线变压器,给出了考虑线圈互耦的等效电路模型,分析了其阻抗变换特性。然后在此基础上,通过实验调试,研制了工作频带为30MHz-450MHz、变换比为1：1．6的传输线变压器,总结出设计任意变换比传输线变压器的一些结论。     

矩形波导分叉问题的阻抗变换分析

本文利用波导的传输线模型及阻抗变换技术，分析了多分叉波导的性质，利用这一方法，使复杂的场问题简化为路的问题，同时根据这一模型分析了在矩形波导中插入二维任意形状的导体情况下电磁波的传输性质，其正确性为实验所证实。     

时域有限差分法分析超导平面传输线

本文采用时域有限差分法（ＦＤＴＤ）分析了高温超导平面传输线。通过共轭偶延拓和逆博利叶变换，使得具有频域表示式的超导二流体模型能够引入到时域分析中，并建立起稳定的差分格式。应用这一方法分析了超导微带传输线及共面波导的衰减特性和色散特性，计算结果和已发表的准静态分析方法比较，一致性较好。说明了该方法对分析超导体的可行性和正确性。     

传输线时域响应分析中的改进型NILT方法

本文利用拉氏变换的推广定义及初值定理，获得一种传输线时域响应分析的改进型数字拉氏逆变换（ＮＩＬＴ）方法。该方法采取了将分析时间分段并进行传输线初始条件重新设置的步骤，因而比传统的ＮＩＬＴ方法精确、有效。     

用波形迭代法分析非均匀多导体传输线的时域响应

本文从频域电报方程出发推出了一个描述传输线ABCD矩阵的微分方程,将传输线时域响应分析从微分方程的边值问题转化为数学上更易求解的初值问题。然后利用波形迭代法数值求解非均匀传输线的ABCD矩阵,证明了一个关于迭代收敛性的定理,并据此采取了旨在加快收敛速度的将传输线分割成许多相互级联的子网络的步骤。传输线的ABCD矩阵求得后,便可借用付里叶变换和卷积技术对具有线性、非线性负载的传输线时域响应进行分析。给出的应用实例表明,诙分析方法是有效而可靠的。     

一维不均匀介质中波传播瞬态响应的传输线模型分析

提出了用传输线模型分析一维不均匀介质中波传播的瞬态响应。这种方法将一维不均匀介质用多层介质近似，并进一步用级联的传输线模型等效。分析的过程是：首先对局限在某一时间段内的输入电磁信号进行傅里叶变换得出其频谱，然后研究该频谱的主要分量在所研究介质中的传播，并得出波传播方向任一截面上瞬态信号的频谱，最后通过快速傅里叶变换得出时域瞬态响应。这种方法适用范围广，数值计算方便，只要离散时间间隔足够小，抽样点数足够大，就能达到一定的精度。     

关于传输线等效集总电路模型的拓展教学

传输线的等效集总电路模型有助于理解和掌握传输线的基本概念,并可用于电特性的仿真分析。本文分别探讨了在教学过程中需拓展的两个重要知识点。其一,在高频工作情况下,需要对含有频变分布参数的传输线进行准确建模,获取相应的等效集总电路模型;其二,在分析多导体构成的耦合传输线时,等效集总电路模型同样值得探究。     

有损均匀传输线的PSpice仿真分析

有损均匀传输线的电压、电流既是时间的函数,也是距离的函数,需要用分布参数电路模型分析.有损均匀传输线方程是偏微分方程,正弦稳态解的手算求解比较复杂.应用PSpice对有损均匀传输线进行仿真分析,可得到传输线上任一点的电压、电流的频率特性和正弦稳态波形.本文介绍了有损均匀传输线的PSpice模型和参数,通过实例说明了其应用方法,通过对比可知仿真分析比手算求解更清晰地阐明了物理概念.     

多导体传输线瞬态响应研究

针对多导体传输线瞬态响应的无源性问题,提出了基于集总等效源模型的多导体传输线瞬态响应模型. 从外场激励下的多导体传输线的频域电报方程解出发,将外场在传输线上激励的分布电压源和电流源与传输线指数矩阵解耦,建立了集总等效电压源和电流源模型. 为避免复杂的傅里叶反变换及卷积运算,推导了集总源模型的时域递推方程. 在此基础上,采用时域有限差分法建立了端接线性负载、非线性负载和外场激励下的不等长多导体传输线瞬态响应离散递推方程. 通过对无损传输线的仿真对比,验证了方法的有效性. 最后,对端接线性负载、非线性负载和外场激励下的不等长多导体传输线瞬态响应进行了试验和仿真分析.       

A new approach for closed-form transient analysis of multiconductor transmission lines

A novel closed-form model for multiconductor transmission lines is presented. The proposed model is derived from the analytical characterization of half-T ladder networks, which using closed-form polynomials (named DFF and DFFz), allow one to exactly extract poles and residues of the two-port representation of multiconductor transmission lines, thus, generating a time domain macromodel that can be incorporated in a circuit simulator. Since the model is derived from a stable and passive equivalent network, its stability and passivity are strictly preserved. Simulation results for one, two, and three-conductor transmission lines with linear and nonlinear terminations are presented, confirming the validity of the proposed model.     

Circuit-Based Analysis of Electromagnetic Field Coupling With Nonuniform Transmission Lines

This paper presents a new algorithm for simulating electromagnetic (EM) field coupling with nonuniform multiconductor transmission lines in a circuit simulation environment. The proposed algorithm is based on the concept of passive model-order reduction, whereby an algorithmically developed passive reduced-order model, coupled with a set of equivalent sources representing the incident filed, are shown to accurately capture the behavior of the transmission line under EM excitation. The reduced-order model is developed independently from the particular shape of the incident field pulse, in the sense that, in constructing the model, one does not need prior knowledge about the waveform of the incident pulse of the EM field. In addition, it is also shown that the model developed can be used to simulate the transmission line in the absence of the EM field. The derived equivalent sources, representing the field coupling, are given directly in the time domain, thereby making simulation under nonlinear circuit terminations an easy task. Although the proposed work is aimed mainly at simulating nonuniform transmission lines, it can be applied to uniform lines as a special case. The proposed algorithm has been validated numerically with several examples.     

工艺参数随机扰动下的传输线建模与分析新方法

本文考虑集成电路制造过程中传输线制造工艺参数随机扰动对传输线传输性能的影响,建立了传输线的随机模型.结合精细积分算法与蒙特卡洛方法分析了该传输线随机模型的瞬态响应,通过对模型输出的正态性进行偏度-峰度检验给出了最差情况估计.对于正弦激励情况推导了无耗传输线相应随机微分方程解的一阶矩的解析形式,给出了二阶矩的数值计算方法,最后估计出输出信号振幅与相移的上下界.实验结果表明本文提出的传输线随机模型及其分析方法可以对传输线的性能进行有效的评估.     

Broadband Resonant-Type Metamaterial Transmission Lines

In this letter, it is shown that, contrary to previous assumptions, the broadband characteristics of metamaterial transmission lines are not exclusive of the so called CL loaded composite right/left handed (CRLH) structures. In the balance condition, the typical frequency gap between the left handed (LH) and right handed (RH) transmission bands of these CRLH lines collapses, the characteristic impedance varies smoothly in the vicinity of the transition frequency, and broadband response results. However, through an appropriate design, similar behavior can be obtained in resonant type metamaterial transmission lines, namely transmission lines loaded with complementary split rings resonators. A detailed analysis of the structures, based on the equivalent circuit model is provided, and implications of balancing are pointed out. In this letter, it is clearly demonstrated that broadband balanced CRLH lines can also be implemented by means of the resonant type approach     

有损土壤上的多导体传输线的时域分析

将多导体传输线（ＭＴＬ）的土壤复数阻抗拓展为土壤运算阻抗,采用Ｐａｄｅ展开法,提出了计及土壤影响的多导体传输线的时域模型,建立了该模型的时域有限差分（ＦＤＴＤ）算法。通过对计及土壤影响的架空单导体和双导体传输线的波过程计算,表明本文方法的正确性,并可以应用于超高压变电站高压母线和超高压输电线路的瞬态电磁干扰计算。     

传输线的随机建模及瞬态响应数值实验分析

该文考虑集成电路制造过程中传输线制造工艺参数随机扰动对传输线传输性能的影响,建立了传输线的随机模型,针对该模型提出了基于蒙特卡洛法的传输线瞬态响应统计分析方法。统计分析中采用精细积分算法求解传输线样本瞬态响应,并对模型输出的正态性进行偏度-峰度检验,给出了最差情况估计。试验结果表明该文提出的传输线随机模型及统计分析方法可以对传输线的传输性能进行有效的评估,对于传输线制造过程的控制及优化有着重要意义。     

Transient analysis of transmission line circuits based on the semidiscretization of telegraph equations

A new transient analysis method for the transmission line circuits is presented in this paper. Based on the semidiscretization of the telegraph equations, a discretized time domain companion models for the transmission lines which can be conveniently implemented in a general circuit simulator such as SPICE is derived. The computation required for the model is linear with time, equivalent to the recursive convolution-based method. The formulations for both single and coupled lossy transmission lines are given. Numerical experiments are carried out to demonstrate the validity of the method.