Experimental Frequency-Domain Characterization of Fundamental Guided Mode Parameters in Coupled Coplanar Waveguide

The experimental method of propagation coefficient and characteristic impedance estimation of fundamental guided modes in coupled coplanar waveguide (C-CPW) is presented in the paper. The method employs feeding transitions which allow to excite desired mode and measure parameters of transmission line with use of standard two-port vector network analyzer (VNA). Characteristic impedance is determined from easily measured propagation coefficient and static capacitance per unit length estimated from time-domain reflectometry (TDR) measurement. The results were checked against numerical data computed with use of the Spectral Domain Approach. Satisfactory degree of convergence between measured and numerical data has been achieved proving usefulness of worked out technique.