Microwave dielectric measurements of ceramic composites at high temperatures

Summary form only given. The authors describe ongoing efforts at broadband, high-temperature characterization of materials at the University of Utah. For narrowband measurements at S and X bands, the cavity perturbation method is used, and the rectangular cavity designs and high-temperature measurement techniques using a fused silica sample holder and a modern network analyzer are explained. Experimental results of zirconia and alumina have been obtained for temperatures up to 1200 degrees C. Broadband measurements at high temperatures were obtained using the open-ended coaxial line technique. For these measurements, a novel probe using metallized, low-thermal expansion ceramics was designed and constructed. A simple and accurate analytical procedure to calculate the complex permittivity of the sample from the measurement of the probe admittance has been developed. Experimental results have been obtained for some ceramic samples for temperatures up to 1200 degrees C.<>