Magnetron Filtering Components Research

In the past, feed through capacitor of the magnetron filter components were all imported and domestic products available for purchase were not mature; In recent years, forced by cost pressures, magnetron manufacturers have increasingly strong demand on filter components Localization. However for commercial considerations, few in-depth studies on the magnetron filter components have been published in the public journals. It can be only seen when companies applied for patents, and most of the research were conducted within the company.Knowing the magnetron noise is the basis for filter component design. This paper summarizes the theory of the formation mechanism of low frequency magnetron noises, guided by the ionic noise theory and mixing theory, with experiment, concludes the distribution characteristics of the lower end of magnetron noise. Applied constant K type filter model on the existing magnetron filter, the cut-off frequency and the designed characteristic impedance of the filter were derived. Those parameters have important reference value for a new type filter design process in the future. Applied filter analysis software analyzes the ideal attenuation characteristics of the exciting magnetron filter, discusses the high-frequency parasitic effects, and makes obtaining a lower parasitic capacitance filter a reality. The new design reduces the margin in a controlled manner on the band lower than 230MHz, at the same time it increases the 450-580MHz band attenuation---where excessive noises appear. With the new design the low overall adoption rate upgraded close to 100%.This paper introduces the choke coil and feed through capacitor manufacturing process, further studies the influence of the conditions of various process conditions such as sintering, molding pressure, sintering atmosphere, etc. on the Electric breakdown, dielectric constant, density and other properties of the barium titanate ceramic based feed through capacitor; discusses the effect of the glass transition temperature of epoxy resin on the feed through capacitor, draws the conclusion that by reducing the glass transition temperature the resistance to thermal shock performance of the finished products can be improved; By researching on the binding ability of the resin and ceramics, it is found that ratio of curing agent and curing condition optimization can reinforce resin and ceramic binding .Finally, with the CST low frequency simulation module, this paper analyzes feed through capacitor working conditions in a inverter microwave oven, proves that an ordinary feed through capacitor would generate too much heat, and withstand voltage cannot be guaranteed in long-term usage. Adaptive transformation scheme was proposed, and the fabrication of the inverter feed through capacitor was finished. Using the same CST low-frequency simulation module, this paper analyzes the capacitor welding process, gets the heat loss distribution caused by high-frequency current on the terminals and the bottom board, then gets the total dissipation, has found the reason that hinders the increase of temperature during the welding process, and proposes the program of increasing the lead to improve the dissipation of the terminals.