Complex permittivity and permeability characterization from transmission-line measurements

Two broadband methods for simultaneously measuring the complex values of the permittivity and permeability of film-shaped materials are presented. The complex properties of these materials are calculated from S-parameter measurements of coplanar or microstrip cells propagating the quasi-TEM dominant mode. The S-parameter measurements are easy to be implement. They are carried out from a network analyzer and on-wafer systems allowing different sizes of cell and covering 0.05-40 GHz. In the case of the coplanar, the dispersion is very low for a cell shape such as h>W+2S. Thus, a fast extraction method of the coplanar substrate properties (epsilon(r), mu(r)) has been developed from analytical relationships. It is faster than the microstrip extraction method, which requires a numerical method for a rigorous analysis of the microstrip cell in order to take into account the quasi-TEM mode dispersion. Measured epsilon(r) and mu(r) data for several materials are presented in the 0.05 GHz to 40 GHz frequency range. These methods show good agreement between measured and predicted values.