Measurement of complex permittivities of plastic resin materials using cavity resonator method with a perturbational theorem

摘要

An evaluation technique for the microwave properties of dielectric materials using cylindrical cavity resonator method with a perturbational theorem is investigated in this paper. The influence of the sample insertion hole on measured results is not negligible in the conventional cavity resonator method. In order to solve this problem, the resonant frequencies and the unloaded Q factors are measured, changing the insertion length of the sample. The complex permittivity is evaluated from their differential coefficients. An automatic measuring system are constructed to keep the accuracy and the efficiency of the measurements. The measured results for some plastic resin materials at 2.4 GHz are shown.