Broadband permittivity determination using statistical techniques

A method for determining the complex permittivity of a material sample is presented. The method uses transmission coefficient measurements made on a transmission line where the sample is the dielectric. The transmission line could be coaxial, waveguide or free-space. The proposed method differs from most because it uses the measurements over the entire frequency range to determine the values. This is in contrast to most techniques that calculate the permittivity at each frequency independently. Measurement results made using a free-space fixture are presented using the proposed method and a more traditionally used method. The measurements included several low-loss materials. The measurements were made over two frequency ranges, 75-110 GHz and 40-50 GHz.