A dielectric resonator for measurements of complex permittivity of low loss dielectric materials as a function of temperature
Abstract
An application of a 0957-0233/9/10/015/img5 mode dielectric resonator is described for precise measurements of complex permittivity and the thermal effects on permittivity for isotropic dielectric materials. The Rayleigh-Ritz technique was employed to find a rigorous relationship between permittivity, resonant frequency, and the dimensions of the resonant structure, with relative computational accuracy of less than 0957-0233/9/10/015/img6. The influence of conductor loss and its temperature dependence was taken into account in the dielectric loss tangent evaluation. Complex permittivities of several materials, including cross-linked polystyrene, polytetrafluoroethylene, and alumina, were measured in the temperature range of 300-400 K. Absolute uncertainties of relative permittivity measurements were estimated to be smaller than 0.2%, limited mainly by uncertainty in the sample dimensions. For properly chosen sample dimensions, materials with dielectric loss tangents in the range of 0957-0233/9/10/015/img7 to 0957-0233/9/10/015/img8 can be measured using the 0957-0233/9/10/015/img5 mode dielectric resonator.
- Publication:
-
Measurement Science and Technology
- Pub Date:
- October 1998
- DOI:
- 10.1088/0957-0233/9/10/015
- Bibcode:
- 1998MeScT...9.1751K