Full-Wave Transmission Line Theory (FWTLT) for a Thin-Wire Transmission Line inside a Rectangular Resonator

This article presents a solution for coupling an electromagnetic field to a thin wire transmission line in a rectangular resonator, with the wire being loaded at the ends and excited by lumped sources. The mathematical model is based on the Telegrapher's equations as a system of ordinary differential equations. The corresponding parameter matrix for the equation system has complex values, is length-dependent and contains diagonal elements. In contrast to free space, the non-diagonal elements for the transmission line in a lossless resonator are purely real and the diagonal elements are purely imaginary. The applicability of a simple perturbation theory for the parameters is investigated.