Microwave characterization of dielectric materials in the temperature range of 90–450 K

In this article, a pressure-controlled sample holder for microwave dielectric measurements in the temperature range from 90–450 K is presented. The experimental set-up involves a coaxial line used to couple a microwave frequency network analyzer and an adapted sample holder in order to obtain dielectric characterization as a function of the temperature. The main innovation of the present work is the technical adaptation in the pressure control of the sample for low temperature measurements. The system was tested characterizing the complex dielectric constant of a Ca modified strontium titanate (SrTiO3) quantum paraelectric-type ceramic material, for which the main physical dielectric properties (orientational or relaxation polarization) in the high frequency region are interesting to be investigated mainly at low temperatures.