Microwave System Design and Dielectric Property Measurements

Abstract

ABSTRACTIn high temperature microwave systems, property variations of the process material can cover orders of magnitude causing significant changes in microwave coupling efficiency, heating rate, impedance matching, field strength and penetration depth. We created some first-order, temperature dependent models of these system parameters for a number of materials and calculated typical values over the temperature range of 0–1000 C. The results show that the input impedance of a resonator, the relative energy dissipation the power density and the penetration depth in the process material are strongly influenced by the temperature dependent dielectric constant. Process control algorithms require models of the system parameters and hence our models are useful for automated microwave processing systems. Moreover, it is shown that the relative dielectric loss factor of the process material can be monitored via the reflection coefficient of the microwave resonator containing the material.