有耗耦合传输线瞬态响应的性质与分析

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,并将其解析解展开为矩阵无穷级数,从数学角度严格地推导出了有耗耦合传输线瞬态响应的两条重要性质。从这些级数还可近似计算ABCD矩阵的值。为了提高效率,采取了将传输线分割成许多相互级联的子网络的步骤。文章最后给出了利用ABCD矩阵分析传输线瞬态响应的方法和两应用实例。与经典的频域模式法相比,该方法完全避免了模式分解的复杂过程,因而其计算机程序更简单,节省了大约一半的内存。     

传输线网络瞬态响应灵敏度分析

在传输线网络瞬态响应灵敏度分析之中,提出了一种基于NILT的新的分析方法。该方法将传输线及其效应连同电子元器件及单元电路作为一个整体,根据传输线在电路中的拓扑关系,将传输线网络瞬态响应灵敏度分析问题转化为求解传输线网络瞬态响应问题,以及传输线ABCD矩阵对电路参数的偏导数问题。通过将ABCD矩阵进行级数展开,极大地简化了ABCD矩阵对电路参数偏导数的计算以及传输线网络瞬态响应灵敏度的分析。本文方法不需要对耦合传输线进行解耦,具有简单、精确、高效等特点,算例结果表明了本文方法的有效性。     

用基于龙格-库塔迭代的NILT进行非均匀传输线的瞬态分析

通过龙格-库塔(Runge-Kutta)方法迭代求出非均匀传输线的广义ABCD矩阵，再解常微分方程求得整个系统的拉氏城响应，最后利用数字拉氏逆变换(NILT)获得电路的时域响应，从而使得传统的NILT法得以分析非均匀传输线，实例表明其具有较高的效率和精度。     

非均匀有耗传输线ABCD参量的求解

传输线理论是射频与微波电路的重要基础理论,而其中ABCD参量特别适用于分析级联网络的传输性能.本文针对非均匀有耗传输线的ABCD参量求解问题,建立传输线的数学模型,给出了三种解法,即级联法、微分方程法和积分方程法,并对三种方法的准确性和效率进行了讨论.     

非均匀传输线ABCD参数的微分方程解法

随着集成电路工艺进入到深亚微米阶段,传输线特性分析对于集成电路设计和优化具有重要意义。针对非均匀传输线的ABCD参数,建立传输线数学模型,通过传输线电报方程推导出ABCD参数满足的微分方程组,并采用龙格-库塔法进行求解得到ABCD参数,最后通过数值算例验证了方法的有效性。     

一种用于分析高速VLSI中频变互连线 瞬态响应的精细积分算法

本文利用精细积分法求解高速VLSI中频变参数互连线的瞬态响应.首先,从频域传输线方程出发,利用反拉氏变换将其转化为含有卷积项的时域方程,经过空间坐标离散后,再采用精细积分法进行求解.与以往的空间离散方法相比较,提出采用电压和电流空间间隔取点的方法,减小了截断误差.在计算常微分方程组中的非齐次项时,采用递归计算代替传统数值卷积大大提高了计算的效率.该方法对于耦合传输线无须进行解耦,在处理非均匀频变传输线时也非常方便.数值实验结果表明,该算法稳定性好,计算精度高.     

背板互连线高速信号传输的计算机仿真

采用ABCD矩阵法对传输高速信号的背板上具有频变参数的互连线建立等效时域网络模型,并给出接插件等效传输线模型和端接的I／O缓冲器IBIS瞬态行为模型,利用这些模型对实际电路进行仿真,其结果与Ansoft公司的PNC软件仿真结果相吻合,仿真效率有明显提高。     

背板互连线高速信号传输的计算机仿真

采用ABCD矩阵法对传输高速信号的背板上具有频变参数的互连线建立等效时域网络模型,并给出接插件等效传输线模型和端接的I／O缓冲器IBIS瞬态行为模型,利用这些模型对实际电路进行仿真,其结果与Ansoft公司的PNC软件仿真结果相吻合,仿真效率有明显提高。     

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。     

传输线时域响应灵敏度分析的精细积分法

给出了一种基于精细积分法的传输线时域响应灵敏度分析法。该方法直接在时域进行,只需进行一些简单的矩阵及递推运算,处理传输线非线性负载和任意形状的激励信号尤为容易。方法简单,计算效率高。     

Novel Analytic Theory for Laser Mode-Locking

The time-domain ABCD matrix formalism is based on the propagation of a Gaussian pulse which is characterized by the pulsewidth and chirp. In this paper, we will perfect this method and derive time-domain ABCD matrices for more optical devices. Especially, we extend this perfected theory to analyze the principle of passive mode-locking by reasonable approximation though, as we know, the output pulse generated from passive mode-locking fiber laser is of sech-shape. It is attractive because it can present a fairly apparent view to understand the mechanism of fiber lasers as well as analytic results to understand the pulse characteristics.     

Analysis of transients in nonuniform and uniform multiconductortransmission lines

The author presents an effective method for computation of the transient response of multiple nonuniform transmission lines. This time-domain analysis technique can predict reflections and crosstalk. The proposed spectral technique is used to transform partial differential equations describing a system of transmission lines into a set of linear ordinary differential equations, which can be solved with one of the many well-developed integration techniques. Numerical experiments performed with the prototype program showed that the method can solve specific problems (lossless, uniform lines) just as fast as less general methods based on modal analysis exploiting the particular properties of lines     

对垂直交叉线中串扰的分析

用修正后的传输线方程对垂直的导体间的串扰进行了频域模拟，通过反傅立叶变换得到时域信号。模拟表明，虽然垂直放置可使串扰幅度大幅度降低，但交叉线中仍有较强的干扰，串扰幅度与各端接入的负载有很大关系，对干扰的原因进行分析。为了证明结果的正确性，对平行导体间的串扰用时域有限差分法和本方法进行模拟，得到一致的结果。该文对实际应用有参考价值。     

基于Upwind差分格式的电缆故障测距仿真系统

波反射法是目前电力电缆故障测距的主要方法,而波反射法采集到的故障波形复杂多变,分析较为困难。因此利用电缆的传输线模型,在分析偏微分方程数值解理论的基础上,提出了基于Upwind差分格式来进行传输线时域分析,并由此建立电缆故障测距仿真系统。检修人员通过仿真软件,学习分析电缆故障测距中可能出现的各种波形,可以提高工程实际中故障点的判断能力。仿真结果表明,仿真波形与工程实际中测试到的故障波形基本一致,能够很好地用于对电缆故障检修人员进行培训。     

Efficient analysis of microwave passive structures using 3-D envelope-finite element (EVFE)

A three-dimensional envelope-finite element (EVFE) technique is proposed to solve the transient responses of general microwave passive structures. EVFE simulates the signal envelope rather than the original signal waveform by de-embedding the carrier from the time-domain wave equation. The sampling rate of the time-domain waveform is only governed by the Nyquist rate of the envelope, rather than that of the carrier in traditional time-domain simulators. Compared to traditional finite-element time-domain (FETD) methods, the computational cost can be dramatically reduced when the signal envelope-to-carrier ratio is very small. It also provides much higher computational efficiency than frequency-domain finite-element methods for simulating frequency responses over certain bandwidth. This technique is applied to solve a waveguide structure with a dielectric post discontinuity and a microstrip patch antenna. The accuracy and efficiency is demonstrated and compared with traditional unconditionally stable FETD methods.     

Analysis of the time response of multiconductor transmission lineswith frequency-dependent losses by the method ofconvolution-characteristics

A new method for analysis of the time response of multiconductor transmission lines with frequency-dependent losses is presented. This method can solve the time response of various kinds of transmission lines with arbitrary terminal networks. Particularly, it can analyze nonuniform lines with frequency-dependent losses, for which no effective method for analyzing their time response exists. This method starts from the frequency-domain telegrapher's equations. After decoupling and inversely Fourier transforming, then a set of decoupled time-domain equations including convolutions are given. These equations can be solved with the characteristic method. The results obtained with this method are stable and accurate. Two examples are given to illustrate the application of this method to various multiconductor transmission lines     

基于精细积分法的耦合传输线瞬态分析

在耦合传输线的瞬态分析中提出了一种基于精细积分法的龙格-库塔迭代法。这是一种时域内的数值解法，该方法在对电报方程进行空间离散而获得对时间的一阶微分方程之后，没有采用精细计算法，而是采用了龙格-库塔迭代法。避免了大量的矩阵运算，提高了传输线瞬态响应分析的效率。     

Efficient Technique for the Cascade Connection of Multiple Two-Port Scattering Matrices

There are several practical applications in microwave engineering that require the cascade connection of multiple two-port scattering matrices. Many microwave devices are analyzed by segmenting the structure into small building blocks (steps, resonators, lines, etc.) that are characterized by means of the generalized scattering matrix. In order to obtain the reflection and transmission parameters of the entire structure, the scattering matrices of all the building blocks must be cascaded. Traditionally, the conversion of the scattering matrices to ABCD or T matrices has been used in order to perform the cascade connection. An alternative to this procedure is to perform a recursive connection by pairs of the scattering matrices. In this paper, we present a new technique for the efficient cascade connection of N monomodal or multimodal scattering matrices that reduces the computation time by 35% when compared to the cascading by pairs, and by 75% when compared with the use of ABCD matrices.     

Experimental Characterization of Multiconductor Transmission Lines in Inhomogeneous Media Using Time-Domain Techniques

An effective method for the time-domain characterization of lossless multiconductor transmission lines with cross-sectionally inhomogeneous dielectrics is presented. Lines of this type are characterized by multiple propagation modes having different velocities. Time-domain reflectometry is used to obtain the characteristics impedance and the modal velocities of the line. A pulse or step-function response of the line is used to obtain the modal amplitudes which, in turn, determine the velocity matrix. The appropriate multiconductor transmission-line equations are solved to obtain the per-unit-length inductance and capacitance matrices in terms of the measured characteristic-impedance and velocity matrices. The method is concise and complete and identifies the propagation modes in a way that permits direct physical interpretation of the results. The time-domain experimental results for a four-conductor transmission line are presented and are found to be in good agreement with independent frequency-domain measurements.