Open resonator technique for measuring multilayered dielectric plates

A generalized formulation of an open resonator technique including multilayer dielectric plates is proposed. It is used for experimental characterization of the permittivity and loss tangent of one of the layers. An experimental measurement system is developed and used to measure the dielectric properties of high-permittivity ferroelectric films, which demonstrates the utility of the approach. The loss tangent of the layer studied is obtained with the analytical formula derived, which speeds the data processing procedure. It is experimentally shown that the air gap between the sample and the plate mirror may significantly reduce the accuracy of the open resonator technique. It is also shown that the formulation developed here provides the means to deal with the problems associated with the air gap.