Broadband complex permittivity measurement of low loss dielectric disks by cylindrical cavity

In this paper, the complex permittivity of low loss microwave dielectric disk is measured in broad frequency band by applying cylindrical cavity. The measurement frequency band covers 7-18 GHz by using only one cavity which works in multimode. The paper mainly discusses the design of the cavity, measurement theory and mode search method after the sample is loaded. The length of the cavity does not need to be tuned during the process of measurements.