Single-Length Method Used to Determine the Dielectric Constant of Polydimethylsiloxane

A new transmission-line method has been developed which is used to determine the propagation constant of a novel microwave material. Rather than requiring two or more transmission-line lengths to determine the propagation constant of a material, our method relies on a single fixture of known length and the use of a dielectric material of known properties to set a baseline measurement. By using a single fixture to make the measurements, we avoid introducing additional parasitic elements that would produce errors. We applied this approach to find the dielectric constant of the polymer polydimethylsiloxane over a frequency range of 0.1-40.0 GHz.