Integration of an FDTD analysis of lossy multiconductor transmission lines within a general-purpose circuit simulator

In this paper, a multiport circuit model for a finite-difference time-domain (FDTD) analysis of the multiconductor transmission line equations is derived. The multiport model enables easy integration of a lossy transmission-line network within a general-purpose nonlinear circuit simulator. The model can be viewed as a link between a distributed-system analysis method, FDTD, and a lumped-element network solver, the circuit simulator. The multiport circuit model consists of resistors and dependent current sources which are updated at every time step by the FDTD algorithm. The approach is capable of dealing with distributed sources, as well as lumped sources. The analysis of a two-conductor transmission line with nonlinear terminations is presented as an application of this approach.