Electromagnetic Compatibility Characteristics Of Continuous-wave Magnetron

The interference of the CW magnetron covers a very wide band,which from 30MHz to 18 GHz. As a result, any household appliance using magnetron as powerresource must reach the EMC limits. Thus the different equipments are prevented to competethe same frequency spectrum and we can pursue a so call "green"household appliance.The research in the EMC of magnetrons is mainly carried on by the manufactories of Japanand Korea. Now our country is started the research, in which the union of WITOL and UESTC isthe forthgoer. Most manufactories developed the EMC of magnetrons depending on the result ofexperiments. It is very difficult for them to get the pivotal thought they have spent lots ofmanpower and money. Therefore we develop an efficient method which bases on the theory andsimulation and experiment as assistant. Furthermore we investigate the cause of EMI, thus themanufactories of magnetrons can gain a research of low cost and short period.This article centers on:1.The article investigates the cause of EMI using the modulation theory. There are twocharacteristic modes in the resonance cavity, which are called πmode and (N/2)-1 mode. Thetwo different frequencies modulate each other, so the interference between 30MHz~1000MHz isproduced.2. If we use a numerical calculation, It is very difficult to gain the frequency of the (N/2)-1mode. Also it is impossible to do some experiments with the existing equipments. Thus the articlesimulates the eigenmode of the resonance cavity with HFSS.3.There are three cases which the cathode and anode is not coaxial. The article compares thesimulation results with that of the coaxial ones. We find out that if the cathode and anode is notcoaxial, there will be some damage to the EMC of magnetrons.