Date of Award
Master of Science in Optical Science and Engineering
Department of Engineering Physics
Michael A. Marciniak, PhD.
The dielectric properties of candidate materials for radomes or sensor windows on hypersonic vehicles, which can reach temperatures above 1,500° Celsius when traveling greater than Mach 5, are required. Although there has been recent scientific interest in the temperature dependence of the dielectric constant, little is known for temperatures near 1,500° Celsius and above. Current research utilizes large laboratory-sized furnaces to achieve these temperatures. This also requires large sample sizes, which are expensive; such expense is greatly multiplied when sweeping through hundreds of materials for research and development. In an effort to reduce these costs, this thesis modeled a 7.0 cm x 2.295 cm x 1.016 cm rectangular waveguide aperture-coupled to a cylindrical cavity designed to operate at a resonant frequency of 10GHz, and utilized the electromagnetic cavity-perturbation technique to optimize the research of small dielectric disk samples placed within that cavity. The objective was to model the much smaller system, produce an empirical relationship between the cavity resonance and the dielectric constant of the sample, and create a prototype of the design to validate the proof of concept. Such samples could then be laser heated to these very high temperatures. As a result, it was found that a disk of 150µm thickness with a small radius, positioned at the center of the resonant cavity, is a viable geometry to produce the sensitivity required for conducting dielectric measurements as a function of sample temperature.
DTIC Accession Number
Arida, Marvin-Ray, "Cavity perturbation technique of 10 GHz cylindrical resonator for modeling RF/IR sensor radomes/windows" (2017). Theses and Dissertations. 785.