Analysis of the Stochastic Electromagnetic Field Coupling to Single and Multiconductor Transmission Line Structures

Abstract

This thesis analyzes transmission lines and their behavior in a reverberation chamber. For this purpose, a time efficient closed-form solution for the coupling of stochastic electromagnetic fields to single- and multiconductor transmission line structures is presented. The simulation model is based on the Baum-Liu-Tesche (BLT) equations, but this thesis goes beyond the study of a coupling to a single plane wave and studies the excitation by a stochastic field. The transmission lines are described analytically using transmission line theory and in addition per-unit-length (p. u. l.) parameters are defined. Based on Maxwell’s equations, a generalized transmission line theory is presented which, however, resembles classical transmission line theory in its structure. The classical transmission line theory is extended to include higher order modes. A high frequency (HF) model is derived for the p. u. l. parameters, in that way that the parameters become frequency dependent. The model of the frequency dependent p. u. l. parameters is deduced and validated by the method of moments and by measurements in the reverberation chamber. Different configurations of the transmission line structures are analyzed and the average magnitude of the coupled voltage at the terminals is calculated and discussed. Moreover, the influence of bending transmission lines and its influence on the field-to-wire coupling is investigated.