Permittivity Measurements Using Spherical Sample Microwave Scattering Technique

Abstract

This paper describes a free space method for measuring the permittivity at X band and higher frequencies over a wide temperature range. Measurements are limited to values of ε′>6 and 10−3<tanδ<0.2. ε′ can be determined to 1 or 2% over a significant range; however, for tanδ the range and accuracy are limited. X band measurements are presented for ZrO2 at room temperature and Al2O3 at room temperature, 1100°C, and 1450°C. Elevated temperature measurements can be performed without heating the microwave components. This method is suitable for use in the millimeter wavelength region. Curves for use in evaluating ε′ and tanδ have been previously recorded by the author [``Values for Scattering by Dielectric Spheres in the Region of the First Resonance,'' NRL Report 6365 (30 December 1965)].