Method to Measure the Dielectric Parameters of Powders in Subterahertz and Terahertz Ranges

On the base of the high quality Fabry-Perot resonator a method for measuring dielectric parameters, namely, the refractive index ( n ) and tanδ values of powder materials, which does not require the measurement of the poured layer thickness, has been developed. The results of measuring the Al 2 O 3 , TiO 2 , ZnO, SnO, and WO 3 metal oxide powders in the frequency range 160-253 GHz and in the temperature range 20−360 °C are presented. The method was developed and tested for a detailed understanding of the processes of powders heating and evaporation under the radiation influence of high-power terahertz (submillimeter) gyrotrons with subsequent condensation in the form of highly pure nanopowders.