Microwave heating apparatus

摘要

The present invention relates to an apparatus and a method for heating a load using microwaves. A transmission line 103 transmits microwaves from a microwave generator 102 to a cavity 101. A sensing device 104 measures electromagnetic field strengths for providing information about the phase and the amplitude of a reflection coefficient representing the ratio between the amount of microwaves reflected back towards the microwave generator and the amount of microwaves transmitted in the transmission line from the microwave generator. A control unit 105 detects whether the measured electromagnetic field strengths correspond to a reflection coefficient having a phase within a certain interval of phases and an amplitude within a certain interval of amplitudes, wherein the certain intervals of phases and amplitudes correspond to an operating region of the microwave generator. The control unit controls feeding of microwaves to the cavity based on this detection.