Rapid High Temperature Measurement of Microwave Dielectric Properties

Abstract

ABSTRACTPractical high temperature (above 500°C) dielectric measurement techniques are reviewed stating both advantages and limitations of known methods. Details of a new and practical dual frequency microwave high temperature dielectrometer are discussed. This dielectrometer technique is capable of measurements beyond 2000°C. Both heating of the small samples and the measurement of their complex dielectric constant is done simultaneously using both a medium power (60W) microwave source and a low power scalar network analyzer. Good accuracy is obtained and the measurement is capable of being totally automated. Presently, a measurement and heating cycle time of about 20 s is needed to completely characterize the sample's microwave dielectric response from 300°C to 1600°C. A second high temperature dielectrometer technique is discussed which requires only one microwave source of medium power level (60W). This method requires only the reflected power to be monitored during the microwave heating of the sample to obtain the complex permittivity versus temperature curve.