Research And Implementation Of Microwave Multi-port Coupled Cavity System

Microwave is an electromagnetic wave having a wavelength between 1mm and 1m and having frequency within 3.0×102~3.0×105MHz. At the end of 1960's, microwave technology has been able to apply in many fields such as heating, drying, sterilization, medical treatment and so on. Now, microwave is a kind of new heating energy. The advantage of microwave heating makes it used widely for industry, agriculture, food industry and life. The application prospects of microwave technology will be wider.In this paper, a microwave heating system is constructed. Our system can assure microwave power transferred effectively to terminal loads. When terminal loads are hugely changed, real-time system can be adjusted automatically. In the case that there was supreme reflect power in terminal load, the reflect power would enter the absorbing load at the three port by circulator. Thus, the work of magnetron keeps always steady.The mode of multi-open feed and microwave power supply of multi-point is introduced to our microwave heating system. In contrast to microwave heater of single-open feed, the heat transfer of multi-open feed system processes equations. Moreover, it avoids firing in the cavity near the single-open feed. Accordingly, our system handles the restricted big power heating problem.The main contents of our paper are as follows. Firstly, microwave heating system which can automatically respond the dynamic change of load is constructed. Secondly, microwave reactor is designed. Coupling coefficient between wave-guide and cavity is calculated. Then the power mutual coupling of wave-guide switch and the method of decreasing mutual coupling are studied. Finally, the performances of analog circuits of measurement and control system are analyzed by simulation soft.