Characterization and Modeling of Faceplates by a Frequency-Dependent Impedance Matrix

The use of non-metallic faceplates for circuit-packs popu- lating an equipment shelf can impact both the Emissions and Immunity characteristics of a system to stimuli with transient and/or steady-state time dependence. The char- acterization of these faceplates in terms of their respective frequency-dependent impedance matrices can be useful in predicting the overall EMC performance of the system. The lumped circuit elements of the impedance matrix for face- plates are derived from the frequency-dependent empirical scattering matrix data generated experimentally for each type of faceplate. Subsequently, the derived impedance matrix is used to develop approximate circuit modes for metallic and non-metallic faceplates. The approximate circuit models are then used to predict and compare the behaviors of faceplates to that of standard metallic face- plates when subjected to arbitrary transient and steady- state stimuli.