Microwave system for in-situ dielectric and calorimetric measurements in a wide temperature range using a TE111-mode cavity

The various developments in microwave material processing have shown that the microwave curing of fiber reinforced plastics can be much more energy efficient compared to conventional heating methods. This motivated the development of different microwave systems and processes. Nevertheless, the accurate knowledge of the dielectric properties of materials at the carrier frequency is one of the keys for successful design of microwave applicators and processes. Therefore, a system for accurate in-situ monitoring of the dielectric and the calorimetric properties during microwave heating has been developed. The dielectric characterization bases on the cavity perturbation technique. The microwave source operating at 2.45 GHz is utilized for both, the cavity resonance properties measurements and the dielectric heating of the material at the same time. A TE111-mode cylindrical cavity having an unloaded quality factor of 11.500 is used as microwave applicator.