High frequency model for the transfer impedance based on a generalized transmission-line theory

Abstract

The transfer impedance and transfer admittance as the characterizing parameters of cables in an electromagnetic environment have been subject of intensive research in EMC. Usually the shields of those cables are composed of braided wires. Existing computational models for the transfer impedance are based on models of the braided shield itself. With the nonuniform transmission line theory it becomes possible to consider these shields as nonuniform multiconductor transmission lines, and to derive the transfer impedance and transfer admittance from the primary per-unit-length parameters of the cable. With this approach the local, location dependent per-unit-length transfer values can be obtained. This paper presents the first step towards such model for the transfer impedance.