Layered ball resonator for permittivity measurement method of high loss liquids at millimeter wavelength

We propose a new method to measure the complex permittivity (CP) of a high loss liquid at millimeter wavelength. The method is based on the use of an exactly calculated quasi-optical layered ball dielectric resonator. A measured liquid is placed outside of the ball and does not disturb the spherical symmetry of the resonator. The dielectric layer between the ball and liquid is used to dose the losses in the resonator inserted by the measured high loss liquid. We found theoretically and after confirmed experimentally the optimal resonator parameters and an operating frequency mode to provide maximum sensitivity during measurement of the CP of liquid. The CP measurement of a water-alcohol solution was carried out using the proposed method. Quite good agreement between theory and experiment was obtained. The package of original computer software applications was designed to automate experiment and calculate absolute CP values of the high loss liquids using experimental data for resonant frequency and Q-factor.