多导体传输线电感矩阵的直接算法

该文针对多导体电感矩阵通常需借助复杂间接方法求解的情况,提出一种多导体传输线电感矩阵的直接算法。利用双细线回路方程构建矩阵模型直接求解电感矩阵,降低了分析复杂度;并采用矩阵运算,在计算电感矩阵的同时求解多导体电流分布,解决了传统间接方法无法进行电流分析的难题。分析过程中采用非磁准近似条件和细线划分,可适用于宽频段、任意导体间距,任意横截结构情况。仿真结果表明,该算法在电感矩阵和电流分布的计算上均有较高精度。     

Exact Analysis of the Wire-Bonded Multiconductor Transmission Line

In this paper, the exact model of a multiconductor transmission line with bonding wires is presented. The model is based on the multiport admittance matrix, and is valid for any number of conductors in the structure. The model shows how to compute the two-port admittance matrix of the wire-bonded structure with direct application to the wire-bonded interdigital capacitor. The model has been validated by means of method-of-moments-based numerical simulation and by experimental work.     

Transmission Line Mode Response of a Multiconductor Cable in a Transient Electromagnetic Field

This paper describes a technique for obtaining the induced worst case currents on individual wires of a multiconductor cable as a result of a transient electromagnetic radiation field. The technique involved a development of the expression for the induced current in matrix form where the mutual coupling terms and the other cable currents are the pertinent parameters. A worst case solution results from the assumption of maximum coupling orientation of the individual wires. A short example and some test results are presented. The test results show wave shapes for inductive and capacitive coupling. The solution for the individual wire current due to a transient electromagnetic field is important, since it will greatly reduce the required number of cable measurements and will allow the development of improved shielding techniques.     

非均匀传输线间的串扰研究

应用时域有限差分法对非均匀传输线间的串扰耦合进行分析。基于细线散射的时域有限差分法分析非均匀结构时,采用阶梯式均匀传输线模型,对非均匀传输线进行分段逼近。针对不等长、线径变化、非平行线和交叉线4种情况分析其参数变化对串扰的影响。研究表明：不等长电缆超出部分长度对串扰耦合幅度影响较小,对谐振频率影响较大;电缆线径的变化对其串扰耦合影响较小;非平行线和交叉线的角度对电缆间串扰的影响较大。     

Analysis of Time Response of Lossy Multiconductor Transmission Line Networks

Systems are considered consisting of an arbitrary number of multiconductor transmission lines joined and terminated by arbitrary linear networks. The fines are assumed to be Iossy, with frequency-dependent parameters. The system is analyzed in the frequency domain, and the inverse Fourier transform is used to obtain the time-domain response.     

Passivity Compensation Algorithm for Method-of-Characteristics-Based Multiconductor Transmission Line Interconnect Macromodels

Computation of passive and compact macromodels of distributed interconnects has gained considerable importance during the recent years. Method of characteristics (MoC) is widely used for macromodeling of transmission lines, however, it may not be guaranteed passive. This paper presents a new algorithm for passivity enforcement of MoC-based macromodels of multiconductor transmission lines. The algorithm is based on the first-order perturbation of the related delay differential equations and can handle single as well as coupled interconnects. Necessary theoretical foundations and validating numerical results are presented.      

三维多导体互连结构交扰问题的时域分析

本文利用时域有限差分法对多导体互连结构的交扰问题进行了分析,提取了各端口的S参数.利用AR模型中的Marple方法及参数提取、修正技术对解进行了优化,从而缩短了计算时间,提高了计算的精度.利用超吸收边界条件大大的减少了网格剖分数,节省了计算机的内存.数值结果揭示了导体间的交扰关系.     

精细计算多导体耦合传输线时域响应

本文在多导体耦合传输线时域响应的分析中，引入一种精细计算法，该方法是一种半解析的计算法，它不同用于传统的基于ＦＦＴ的频－时域转换的分析法，而是直接在时域内分析，并且不需要对耦合的电报方程进行解耦，具有快速，简便，准确等优点。     

高速集成电路中多导体传输线的电磁参数提取与瞬态响应分析

本文在直线法中引入了一种新技术，将多层介质多导体结构的各层介质等效为级联的坪端口网络，介质层间导体等效为端口的电流源，从而大大简化了公式推导，方便了编程计算。     

平行传输线间串扰的仿真及分析

在高速电路设计中,信号完整性问题越来越突出,已经成为高速电路设计师不可避免的问题。该文重点研究了平行传输线间的串扰问题,通过信号完整性分析软件Hyperlynx建立了三线串扰模型并进行仿真分析,最后提出高速PCB设计中减小串扰噪声的策略。     

Enhanced Periodic Structure Analysis Based on a Multiconductor Transmission Line Model and Application to Metamaterials

We propose to model periodic structures by equivalent multiconductor transmission lines (MTLs). The developed technique is based on a multimodal representation of the periodic structure unit cell, such as required for periodically loaded MTLs and periodically loaded waveguides with higher order evanescent mode interaction between cells. Compared to commonly employed periodic structure analyses which only provide the dispersion diagram, the proposed method provides all the parameters needed to accurately model the excitation and matching of finite-size periodic structures. The usefulness of the method is illustrated by means of two examples of negative-refractive-index metamaterials. First, a loaded MTL known as the shielded mushroom is analyzed. The proposed technique allows addressing the fundamental issue of the excitation of the different propagating Bloch modes supported by such a structure. Second, a split-ring resonator and wire metamaterial is analyzed. The method is shown to accurately represent the coupling between cells, thereby providing an enhanced design tool compared to the dominant-mode analysis usually employed for this type of metamaterials.      

Impedance Characteristics of a Class of Multiconductor Transmission Lines

The characteristics of TEM modes propagating along a conical transmission line consisting of equiangular strips and exhibiting N-fold symmetry are investigated. Impedance eigenvalues for the eigenmodes of such structures are evaluated using no integral equation approach. Two techniques of calculating the eigenvalues are investigated and compared for this class of transmission line. The results are also compared to exact results available for self-complementary structures. Transverse field distributions along the conical line are also presented for the case N=6.     

Multiconductor Transmission Lines in Inhomogeneous Bi-Anisotropic Media

An analysis method for multiconductor transmission lines embedded in inhomogeneous bi-anisotropic media is presented. The Maxwell-Boffi equations, accompanied by the Maxwell-Minkowski ones, are expressed as Taylor series of the operating frequency where the zeroth- and first-order terms are retained. The reduced problem is solved using the potential formulation through the static 2-D free-space Green's function. The method of moments is employed to numerically solve the set of quasi-TEM integral equations, to produce the Telegrapher's equations, and to derive the circuit parameters in matrix form. The procedure is augmented by providing in closed form the field-coupling integrals.     

耦合传输线信道传输矩阵建模及串扰抵消效果分析

针对高速互连系统中传输线上的串扰问题,基于电磁耦合理论,研究了耦合传输线信道传输矩阵的性质,建立了以下两种情况的耦合传输线信道传输矩阵模型及其矩阵分解形式,分别是：（1）考虑受扰线两边各一条相邻微带线对受扰线的串扰;（2）考虑受扰线两边各两条相邻微带线对受扰线的串扰.给出了上述两种情况下基于耦合传输线信道传输矩阵分解形式的串扰抵消方案,并利用仿真工具ADS对其进行了验证.结果表明：信号抖动和失真大幅下降,串扰抵消效果良好,并且第二种情况下的串扰抵消效果优于第一种情况.该结果说明了在基于耦合传输线信道传输矩阵进行串扰抵消时,考虑两边各两条相邻微带线的串扰效果较好,对保持高速信号完整性具有一定的实际应用价值.     

The Effect of Discontinuities in a Multiconductor Line on Lightning-Induced Voltages

The effect of discontinuities in a transmission line on lightning-induced voltages is studied using a new field-to-line coupling model. For a shielding wire with an isolated grounding, it is shown that the mitigation of the induced voltages is due to the actuation of the localized grounding, when it is illuminated. It protects the line at its location and behind it, reducing the induced voltages by an amount that depends on the grounding resistance and the geometry of the conductors of the line, and also protects some points in front of it, but only within a certain “effective distance” that is dependent on the rise time of the induced voltages. For a periodically grounded shielding wire, it is shown that the reflection, at the grounding points, of the voltage reduction waves produced by the other groundings, produce oscillating induced overvoltages that are mainly confined in the line span in front of the strike. The effectiveness of the shielding wire can be enhanced if the insulation of the shielding wire is utilized as a protective gap. It is also shown that the effect of the ground resistivity is very important but is very different depending on the permittivity of the ground.      

Characteristic Impedances of Multiconductor Strip Transmission Lines

The design of certain log-periodic microwave circuit elements requires a knowledge of the characteristic impedances of a system of four-coupled strip transmission lines. The system of four strip conductors between parallel ground planes is capable of supporting four different TEM modes which have different characteristic impedances. In this paper, the characteristic impedances of the four modes are determined by a variational method. The variational solution is an upper bound to the exact characteristic impedance of the line. In general, the coplanar strip conductors are located at an arbitrary (but identical) displacement from the parallel ground planes. When the separation between the broadside-coupled strips is precisely one-half the spacing between the parallel ground planes, two of the mode impedances may be determined exactly by means of conformal mapping. The variational solutions are compared to the exact solutions for this special case. Because of the "cell image" principle which holds for the problem, the mode solutions presented here also apply to various single- and two-conductor strip transmission lines with arbitrary displacements. As a result, solutions for the following strip line configurations are available from the analysis: a single strip conductor in a trough, or between parallel ground planes; two coplanar strips between ground planes; two broadside-coupled strips in a trough, or between parallel ground planes. An extensive set of curves are presented which show the characteristic impedances of the four modes as a function of the relative dimensions of the strip transmission line.     

Multiconductor Transmission Lines In Multilayered Dielectric Media

A method for computing the capacitance matrix and inductance matrix for a multiconductor transmission line in a multilayered dielectric region is presented. The number of conductors and the number of dielectric layers are arbitrary. Some of the conductors may be of finite cross section and others may be infinitesimally thin. The conductors are either above a single ground plane or between two parallel ground planes. The formulation is obtained by rising a free-space Green's function in conjunction with total charge on the conductor-to-dielectric interfaces and polarization charge on the dielectric-to-dielectric interfaces. The solution is effected by the method of moments using pulses for expansion and point matching for testing. Computed results are given for some cases where all conducting lines are of finite cross section and other cases where they are infinitesimally thin.     

Losses on Multiconductor Transmission Lines in Multilayered Dielectric Media

For the transmission-line modes, a multiconductor transmission line in a multilayered dielectric medium can be characterized by four matrix parameters the capacitance matrices [C], the inductance matrix [L], the shunt conductance matrix [G], and the series resistance matrix [R]. The first two matrices [C] and [L] can be obtained from equivalent electrostatic and magnetostatic problems. The conductance matrix [G] can be obtained by changing all dielectric constants epsilon/sub i/ to complex dielectric constants /angle over epsilon/sub i/ in the equivalent electrostatic problem. The resistance matrix [R] can be obtained by applying a perturbation method to each mode of the transmission line. A computer program has been written for an arbitrary line, and sample computations are presented.     

On the Quasi-TEM Modes in Inhomogeneous Multiconductor Transmission Lines

We consider the general inhomogeneous shielded N-conductor transmission line and derive several properties for the quasi-TEM modes. The concept of quasi-TEM is deduced through an asymptotic series expansion of the fields and conditions for the propagation constant as well as the construction of the field are presented. It is seen that the problem is reduced to two static two-dimensional boundary value problems. The concepts of propagating modes and impedance modes are introduced and it is shown, that in the general case, these are not the same. The special cases of propagating impedance modes are finally discussed and are seen to exist under certain symmetry conditions of the multiconductor line.     

Transient Response of Multiconductor Transmission Lines Excited by a Nonuniform Electromagnetic Field

The time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field, are derived from Maxwell's equations. Depending on how the line voltage is defined, two formulations are possible. One of these formulations is considerably more convenient to apply than the other. The assumptions made in the derivation of the transmission-line equations and the boundary conditions at the terminations are discussed. For numerical calculations, the transmission -line equations are represented by finite-difference techniques, and numerical examples are included.