Characterizing the TEM Cell Electric and Magnetic Field Coupling to PCB Transmission Lines

This paper presents the models of the coupling between the transverse electromagnetic (TEM) field generated in the TEM cell and the arbitrarily oriented microstrip (MS) lines and coplanar waveguides (CPW). The lines are modeled in the frequency and time domain by taking into account different geometries and two types of subminiature version A connectors. The method of lines is used to calculate the capacitance matrix for the MS and CPW lines inserted in the TEM cell. The capacitance matrix is then used to calculate the inductance matrix, i.e., self- and coupling inductances. A number of simulations are performed in order to obtain the set of capacitance and inductance matrices for various line geometries. These results are fitted by using linear regression models. The closed-form equations for the coupling parameters are derived. The closed-form equations are used for the evaluation of coupling of arbitrarily oriented lines. The coupling models are compared against the measurements and found to be very accurate and can be used for efficient coupling modeling between the MS and CPW lines and TEM cell.