A method to measure dielectric parameters in 5–0.5 millimeter wavelength band

The method to measure parameters of dielectric plates by placing them into the Fabry-Perot resonator is modified to provide, relative accuracies: for the resonance frequency of the plate 10^?6; for the refractive index and the plate thickness 10^?4–10^?5; for the loss tangent 5%. Tje values of loss tangent which can be measured are from 10^?6 to 10^?1. The device calibration is performed by a gas frequency standard in 5–0,5 mm wavelength band.