Time-domain simulation of large lossy interconnect systems on conducting substrates

The most general class of uniform transmission-line systems is considered, assuming that samples of the frequency dependent parameter matrices R, L, G, and C are given. In particular, substrate effects which influence wave propagation along integrated circuits (IC) interconnects typically over a very broad range of frequencies are included. A time-domain simulation technique which can handle this problem is described in detail. The algorithm can be embedded in general-purpose circuit simulators and is based on modal analysis, mode tracking, modal delay separation, broadband rational function least squares approximation directly in partial fraction form, and recursive convolution. A numerical example for realistic geometry and material parameters of the examined transmission line structure shows the significance of substrate effects in the frequency and-more important-in the time domain.