Hybrid S-Parameters for Transmission Line Networks with Linear/Nonlinear Load Terminations Subject to Arbitrary Excitations

We propose a generalized S-Parameter analysis for transmission lines with linear/nonlinear load terminations subject to arbitrary plane wave and port excitations. S-parameters are prevalently used to model transmission lines such as cable bundles and interconnects on printed circuit boards subject to port excitations. The conventional S-parameter approach is well suited to characterize interactions among ports. However, non-traditional port excitations associated with plane wave coupling to physical ports at transmission line terminals lead to forced as well as propagating modal waves, necessitating a modification of the standard S-parameter characterization. In this paper, we consider external plane wave excitations as well as port (internal) sources, and propose a hybrid Sparameter matrix for characterization of the associated microwave network and systems. A key aspect of the approach is to treat the forced waves at the ports as constant voltage sources and induced propagating modal waves as additional entries (hybrid S-parameters) in the S-parameter matrix. The resulting hybrid S-matrix and voltage sources can be subsequently exported to any circuit solver such as HSPICE and Advanced Design System for the analysis of combined linear and non-linear circuit terminations at ports. The proposed method is particularly suited for susceptibility analysis of cable bundles and printed circuit boards for Electromagnetic interference evaluations. It also exploits numerical techniques for structural and circuit domain characterization and allows for circuit design optimization without a need to perform any further computational Electromagnetic analysis.