Microwave Oven Magnetron Magnetic System Simulation Analysis

Since magnetron was invented, it has being gradually improved by people's active exploration and research with development of relatively advanced production technology and ultimate achievement of mass production. This puts forward the process from military to civil and industrial application. Especially, continuous wave magnetron has been early and widely applied in household microwave oven and industrial microwave heating equipment.At present, almost several millions of microwave oven magnetrons are produced every year. Demand advances innovation of products and development of technology; competition boosts reductions of cost and price. Therefore, it is undoubtedly a challenge that advantages of low cost, high reliability, long lifetime and low noise are guaranteed at the same time in the research course.The magnetic field of magnetron, an important parameter, being different from that of linear beam microwave tube, directly has effects on interaction and energy conversion of electrons of tube, then on output power, efficiency and noise. When analyzing and discussing operational principle and performance parameter of magnetron, people always hypothesize operational magnetic field as uniform one and draw many conclusions under uniform magnetic field. Nowadays, people began to pay attention to the effect of magnetic field on output characteristic of magnetron, especially on operation stability of tube and output spectrum in the research of improving spectrum characteristic of heating magnetron. Meanwhile, people try to improve output spectrum of magnetron through changing distribution of operational magnetic field to reduce electromagnetic interference EMI of magnetron on some wireless communication equipments. Above all, in this paper experimental measure and software simulation research on magnetic system of magnetron are made, in the purpose of optimizing operational performance ofmagnetron through magnetic circuit design.The paper simulates magnetic field of magnetron by using MAFIA simulation program module of magnetostatic field, and validates reliability of simulation program through practical measure, simulation and comparison. On this basis, magnetic circuit structure is changed including inclination angle in the cone part of pole and height of pole, and changing trend of magnetic field is analyzed to further optimize parts size and improve performance in the course of processing sample tube. In consideration of reducing cost, magnetic field in magnetic circuit system of shortened pole is mainly analyzed. The change of magnetic field and the effect on performance parameter of magnetron are observed, after pole is shortened. Moreover, the performance level equaling that when pole is not shortened can be reached through the optimized design. In this paper, based on the view that magnetic field in periodic changes can improve EMC performance brought by international community, simulation and modeling are made to qualitatively analyze changing law of the magnetic field.