Study of the relationship between the intrinsic Q-factor of a volumetric wave resonator and the error in determining the dielectric constant of a material

Abstract

To achieve high accuracy in determining the dielectric properties of materials using guide cavity, measurements are performed using resonant oscillation with high Q-factor. The error in determination of the resonant frequency is considered given a priori in calculations of the dielectric permittivity and the dielectric loss tangent, whereas the dependence of the error of dielectric measurements on the resonance oscillation Q-factor is out of scope. We present the results of studying the relationship between the resonance frequency, Q-factor and resonating cavity transmission factor. Proceeding from the analysis of the shape of the resonance curve as a frequency dependence of the transmission factor, we determined a relationship between the error of the resonant frequency and Q-factor of the oscillations used for measuring the dielectric properties of the material. This is especially important when measuring the temperature dependences of the dielectric permittivity of materials under their heating at super high frequencies (SHF), when the conductivity of resonator walls and the Q-factor of resonant oscillations decrease as the temperature goes up. It was demonstrated that enhancing of the accuracy of measuring the transition factor is a provision for achieving the required accuracy of measuring the dielectric properties of materials at a lower values of the resonator Q-factor. The results obtained can be used in studying high-temperature resonator devices intended for measuring the dielectric properties of materials in SHF range.