| Popis: |
This thesis describes studies that were carried out on Ceramic Matrix Composite (CMC) materials. These materials were provided by the Air Force Research Laboratory for evaluation in the millimeter-wave frequency region with the goal of developing Non-Destructive Evaluation techniques. This thesis centers on describing the measured reflections from an Oxide/Oxide and SiC/SiNC CMC materials. Models were derived from the Fresnel equations to account for the reflected and transmitted waves in these materials. System models were developed to describe the power coupling of the spectra measured in three separate measurement systems. Using these models the complex index of refraction was determined for the Oxide/Oxide material, and the front surface reflectance was determined for the SiC/SiNC material. A discussion of changes in sample optical properties due to material fatiguing will be included. This document will conclude with the complete spectra and statistical analyses of the Oxide/Oxide, and SiC/SiNC materials at 140-220, and 585-630 GHz. |
