Determination of microwave electrical characteristics of boron nitride at high temperature

The microwave electrical characteristics of a powder Boron Nitride, BN, are determined at high temperature it term of the complex permittivity. The real and the imaginary parts of the complex permittivity are measured using the shift on frequency of the full computerized cavity perturbation technique working in microwave frequency ranges, 615 MHz, 1412 MHz, 2214 MHz, and 3017 MHz, and at temperature from 25 degrees C to 2000 V in step of 50 degrees C. The temperature and frequency-dependent electrical conductivity, sigma, of BN is calculated using the complex permittivity imaginary part, epsilon" measured in the microwave frequency and the temperature ranges of the above technique. The frequency exponent n, and the activation energy, E-A is determined using the calculated electrical conductivity, sigma, in the same microwave frequency and the temperature ranges. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.