S-parameter broadband measurements of microstrip lines and extraction of the substrate intrinsic properties

A measurement technique for the broadband determination of the complex permittivity and permeability of isotropic film-shaped materials is presented. ¿r and ¿r are computed from S-parameter measurements of microstrip lines propagating in the dominant mode and used as cells. The material under test is the microstrip-line substrate, which is the original feature of this method in comparison with existing techniques. This leads to a simple and reproducible measurement process. Measurements for several materials in the 0.05-40 GHz frequency range show good agreement between measured and predicted data.