Effective Broadband Permittivity Measurements of Geological Materials

Abstract

It is a commonly held belief that broadband permittivity measurement techniques have great uncertainties in dielectric loss for low-loss materials, which is unfavourable for applications in planetary and asteroid radar mapping. While true, much of the literature has neglected to address in detail how accurate and effective broadband permittivity measurements truly are. The optimal accuracy is often cited as ± 5% for low to medium loss materials [1]. This thesis reports on the development of a procedure to perform the most accurate and repeatable permittivity measurements of granular materials using a coaxial airline. A detailed uncertainty analysis comprising all sources of uncertainty is presented. Measurements of materials with well-known dielectric properties are performed in order to validate the reliability of the laboratory setup, refined sample handling, and measurement procedure. Although the results suggest this as a reliable technique for dielectric constant measurements, they reaffirm the conclusion of poor accuracy in dielectric loss measurements.