Abstract
A novel measurement method is proposed to evaluate the complex permittivity of material by using a cylindrical cavity resonator. The conventional cavity resonator methods have been based on the simple electromagnetic field analysis, and a rodlike sample should be loaded all the way from the top to the bottom of the resonator. However, the method proposed in this paper employs an accurate and efficient hybrid electromagnetic analysis method for the evaluation of materials and removes the restriction on the size of the sample materials. The radius and length of the sample are chosen considering the electrical characteristics of the sample, and the fact allows the expansion of the application range of the evaluation method to the materials with higher permittivity and/or higher loss. Also, the sample is not loaded in the insertion opening of the resonator in the proposed method. Therefore, it prevents the leakage of electromagnetic fields through opening and improves the accuracy of the evaluation of material with higher permittivity and/or higher loss. Complex permittivities of a few samples of ceramics with high permittivity and lossy electromagnetic absorber are measured in a microwave range to show the validity of this method.