Time-Domain Simulation of n-Coupled Transmission Lines

摘要

A general SPICE model for n-coupled transmission lines is presented. The model consists of two identical transformation networks and n single transmission line models. The transformation networks are realized with linear time-invariant voltage controlled voltage sources and current controlled current sources only. A simplified model designed to simulate connections on multilayer printed circuit boards is also presented. In this case the coupling model is adequately described by a capacitance matrix C and an inductance matrix L that are Toeplitz, symmetric, and tridiagnonal. The structure of C and L makes the computation of the parameters of the transformation network extremely easy and efficient because only simple function evaluations (cosines) are required. The transformation network depends only on the number of coupled lines and not on the parameters of those lines. A library of such models needs to be determined only once and only the characteristic impedances and times delays for the single lines have to be recomputed. Simulation and experimental results differ by less than 1%.