Magnetron Output Performance Test And Multi-cavity Coaxial Structure Research

Microwave technology,as a frontier technology in modern society,plays an important role in many industries.Magnetron,as a widely used microwave source,has the characteristics of small weight,small volume,high output,etc.,so it is of great practical significance to study it.With the development of technology and the change of social demand,millimeter wave frequency band microwave source has gradually entered the production and life,mainly reflected in the military industry,medical treatment,communication and other fields.This thesis studies a Ka-band multi-cavity coaxial magnetron structure,through the accumulation theory to the magnetron cavity design,and then to the competition mode attenuation,finally through the software simulation to achieve the magnetron simulation output.The matching relationship between the load and the output of the magnetron is explored.The main tasks involved in the thesis are as follows:1.Read a large number of journal papers related to the development of microwave technology,especially magnetron technology,to sort out the development context and clarify the overall direction of research.To investigate the latest research results related to magnetron at home and abroad in recent years,extract the essence from them,and integrate some into their own design ideas.2.In-depth study of magnetron design theory and working principle.In the cavity design,the whole is divided into parts to analyze and study the rules one by one,and then the rules of each part are integrated into a whole to obtain the final appropriate cavity parameters that can meet the design requirements.3.The cavity is simulated and analyzed in detail by electromagnetic simulation software.In the stage of cold cavity design,the original design parameters are calculated according to the design requirements and empirical formulas,and then the field distribution,current flow direction and quality factor of cavity mode are observed under different conditions by repeatedly scanning eigenvalue simulation,so as to comprehensively determine the appropriate cavity design parameters.After analyzing the field and current distribution of the interference mode that may produce competition to the working mode,a targeted installation of attenuating ceramic device is adopted to solve the problem.Finally,in order to transfer the energy generated in the magnetron to the external load,an energy output device is designed.4.On the basis of cold chamber simulation,hot chamber PIC debugging is carried out.Firstly,several important parameters are explained and their definitions and properties are analyzed.Then PIC simulation parameters are set,and each parameter is scanned to find the influence rule of its change on the output.Then,the influence of these parameter changes and the addition of the new structure on the design results of the cold chamber was comprehensively analyzed,and repeated adjustment was carried out.Finally,the output of 56.8k W was obtained at the working frequency of 34.7GHz,and the working efficiency was 47.8%.5.Perform the magnetron output performance test.In order to obtain the characteristics of the transmitting and reflecting signals under different load matching conditions,a testing platform was built by using the magnetron of household microwave oven,and the characteristics of the parameters such as amplitude,spectrum and phase under different load conditions were analyzed.Some physical laws of application value were obtained.