Measurement of Uniaxially Anisotropic Dielectrics With a Fabry–Perot Open Resonator in the 20–50 GHz Range

Measurement results of uniaxially anisotropic materials performed with the aid of a plano-concave Fabry–Perot open resonator in the 20–50 GHz frequency range are presented and discussed in this letter. It is shown that a linear polarization of Gaussian modes applied in the characterization allows extracting in-plane complex permittivity of such materials as crystals and foils in a single measurement cycle. It is also shown that dielectric losses exhibit anisotropy, which can be quite significant, like in the sapphire, or relatively small, like in polymer foils.This work was supported in part by the TEAM-TECH Project titled "High-precision techniques of millimeter and sub-THz band characterization of materials for microelectronics" operated within the Foundation for Polish Science TEAM TECH Programme co-financed by the European Regional Development Fund, Operational Programme Smart Growth 2014–2020; in part by the European Metrology Programme for Innovation and Research (EMPIR), under 18SIB09-TEMMT project (EMPIR programme is co-financed by the Participating States and from the European Union's Horizon 2020 Research and Innovation Programme); and in part by the Warsaw University of Technology within the Internal Project "Light-matter interaction." of dielectric micro-resonators with microwave photons in a Fabry–Perot open resonator