Impedance analysis of transmission line cells for EMC applications using Agros2D

When designing a TEM transmission line cell for electromagnetic compatibility susceptibility or immunity tests, its input impedance must be properly defined in order to deliver the maximum power to the device under test. The closed-form solution, relating the cell geometry with the characteristic impedance Zc, is possible only for the simplest “canonical” transmission line transverse cross-sections. The numerical methods must be used for arbitrary geometries instead. In this paper, we propose fast, robust, and accurate approach, based on fully hp-adaptive higher-order finite element electrostatic formulation. The approach is implemented in our in-house software Agros2D. The method applies for the impedance solution of an arbitrary TEM transmission line cell, any TEM transmission line with negligible losses, as well as for analyzing the effective electromagnetic properties of lossless complex stratified media.