Methods to Increase Capacitance in a Gap-Coupled Coaxial Resonator to Perform Dielectric Characterization Using Reflected Group Delay

This paper presents two different methods to increase the capacitance in a gap-coupled coaxial resonator for characterizing dielectric materials. The increased capacitance allows the dielectric characterization of materials over a wider range in terms of dielectric constant and loss tangent. A resonator employing the methods to increase capacitance is designed using ANSYS Electronics Desktop. Simulation results are used to demonstrate the effect of these methods in dielectric characterization of materials with dielectric constant in the range of 2.1 to 7.1, and loss tangent from 0.001 to 0.03. Testing is done to determine dielectric constant and loss tangent of coffee and rice to extend the characterization of dielectric to food materials.