Microwave measurement of the dielectric constant of high-density polyethylene

The method of using interference spectra for determining the dielectric constant, which previously has been developed for semiconductors with dielectric constants of 10-20, has been shown also to yield reliable data for a plastic material, polyethylene, with a dielectric constant of only about 2. Since, for most polymers, the dispersion is very small in the radio-frequency-to-microwave range and the microwave measurement is both very simple and accurate, the interference method may find technical application in material characterization. Prerequisites are a low loss tangent and, hence, good transmission through the thick sample