SPICE Models of Shielded Single and Multiconductor Cables for EMC Analyses

This article introduces novel SPICE models for coaxial cables with braided shielding over a ground plane. The models are derived from the transmission line theory for single and multiconductor cables. They can be used to calculate the voltage at the termination loads when an incident uniform plane wave couples to the cable. The models can also calculate the conductive coupling due to lumped sources. They take into account the bidirectional coupling between the inside and outside of the shield and enable the analysis of immunity and emissions. The coupling functions between the inner and outer systems are designed in the form of equivalent circuits, which allow the use of the models in the frequency domain or together with nonlinear elements in the time domain. The results of the models agree very well with those of field simulations.