Characterization and modeling of faceplates by a frequency-dependent impedance matrix

In designs where conducting faceplates provide access to frame ground for their respective printed circuit boards, the faceplates constitute a crucial segment of the frame ground bus for the system. The use of alternative materials for faceplates raises the need for a direct method of measuring and ranking the faceplate impedances. In this paper, elements of the impedance matrix for faceplates are calculated from the frequency-dependent scattering matrix data generated experimentally for identically dimensioned faceplates made of different materials. The derived elements of the impedance matrix are used to develop approximate circuit models for the tested faceplates. The method reported here can be used to compare and rank the expected performances of alternative-material faceplates with respect to standard metallic faceplates.