Calorimetric Microwave Loss Measurements of Granular Materials

Abstract

AbstractDirect calorimetric evaluation of the microwave loss of dielectrics is possible for granular materials. A cylindrical sample is heated by the microwave field of an incident wave in a rectangular guide and simultaneously cooled by a gas flowing through the bed.A mathematical model describing the energy balance and the heat transfer between the microwaves, the materials and the gas is proposed. It is shown that it is possible to determine, simultaneously, the temperature of the material and its microwave dielectric loss from the measurement of the exhaust gas temperature when thermal equilibrium occurs.