Reseach On Microwave Oven Magnetron Harmonic Suppression

Magnetron(MGT) is a type of quadrature oscillator with reentrant cavity structure, is a kind of high output power vacuum microwave source. MGT is the most widely used in microwave tube of a high power device for its high efficiency, high power, low working voltage (relative to the linear note microwave tube), simple structure, small volume, light weight, easy to use, the advantages of high reliability and low cost. MGT not only apply in the military field, such as radar, microwave weapons, but also widely use in civil operators, such as communication, medical device, industrial heating and microwave oven, magnetron is most widely applied in microwave oven. As time goes, more and more people pay attention to the microwave electromagnetic interference for its high output power which ranged from 500W to 1000W. Test pass rate of microwave oven is determined by the MGT EMI function.it have bring about more scholars and engineers to involve in.because of the theory of electromagnetic compatibility(EMC) is not perfect, so far, engineers improve MGT EMI function by change the position and space of rings, optimize the shape of magnetic pole and cathode position, add choke structure. This paper study choke structure firstly, then propose a theory of filter-antenna, and optimize the production process to improve MGT EMI function.In this thesis, the main researching contents are listed as follows:1. Magnetron’s history, present situation, future development trends are introduced. The background of EMI and the reason for selecting title are stated clearly.2. The components of MGT and the connection relation are introduced. The theory and principle of MGT, the mode of simulation are also expounded, introduce the EMI function of MGT, testing standard and method.3. Choke structure inhabiting six harmonic is designed, which provide a new train of thought for studying.4. The plan of filter-antenna is proposed, some relative simulations and experiments are arranged.5. The EMI function of MGT improve by control the cutting size of gas-piper.