Stability of microwave heating of ceramic materials in a cylindrical cavity

Microwave heating of ceramic materials in a cylindrical wave field is analyzed by numerical simulation. The issues of temperature uniformity and stability inside the sample undergoing microwave heating are addressed. The heating regimes leading to development of global and localized thermal instabilities are illustrated. The role of the temperature dependence of the material's microwave dielectric properties in the formation of instabilities is demonstrated. The tuning and matching of a cylindrical cavity containing the sample is analyzed within a simple model for the microwave and millimetre-wave frequency ranges.