Analysis of a double folded stub microstrip structure using generalized telegrapher equation

Abstract

This paper presents a generalized transmission-line theory which is useful to describe the local radiation effect along almost arbitrary 3D wire structures. For the generalized transmission-line theory, the mathematical structure of the classical telegrapher equation is preserved, while the coefficients (the per-unit-length parameters) are generalized in order to represent the intrinsic behavior of the wire structure. For the double folded stub microstrip structure, the generalized telegrapher equation whose coefficients are determined by dynamic numerical methods can have broadband frequency characteristics. To the investigated microstrip structure as a band stop filter, the S parameters for a frequency band from 3GHz to 18GHz can be calculated by using only one group of the extracted per-unit-length parameters at a frequency of 12GHz, while the generalized telegrapher equation is only established on the central transmission line rather than on the whole structure with the stubs.