The Design And Simulation Of Millimeter Wave Extended Interaction Devices And Collector

The extended interaction device has the characteristics of light weight,small size and compact structure,and can realize high power output in the terahertz frequency band of millimeter wave or even higher frequency,which is extremely important for the development of millimeter wave and terahertz technology.In an extended interaction device,the high frequency field can interact with the electron beam,and the electron beam transfers a small portion of the energy to the high frequency field,but most of the energy is lost through the heat,making the electron efficiency low.One of the important ways to increase the efficiency of extended interaction devices is to use a multi-stage depressed collector(MDC).The multi-stage depressed collector collects a large amount of energy from the interacting electrons,which greatly improves the efficiency of the extended interaction device.Computer simulation and auxiliary design play an important role in the design of the device.In this thesis,the multi-stage depressed collector of axisymmetric structure is designed by computer aided design software.The efficiency of the collector is improved by optimization,and the goal of improving the efficiency of the whole tube is achieved.In the thesis,the related theory of multi-stage depressed collector is analyzed in depth,and then the extended interaction oscillator(EIO)and the three-stage depressed collector are designed by 3D computer aided design software CST.Thermal steady state analysis was performed by CST co-simulation.The main work of this paper is as follows:(1)Explains the working principle of the extended interaction oscillator,and expounds the significant advantages and working principle of the multi-stage depressed collector.(2)By using cold cavity simulation and thermal cavity simulation,design EIO working at 35 Ghz,the power reaches 3059.33 W,and the efficiency reaches 19.24%.(3)Through the CST,the result of interaction between the electron injection and the high-frequency field after entering the EIO is obtained.The energy distribution curve of the electron injection is analyzed as the collector inlet condition,and the multi-stage stepdown collector is calculated.(4)By changing the electrode voltage of the collector and the length of the vertebral body,the efficiency of the collector when using different shapes of the emitting surface is compared,and a multi-stage depressed collector with an efficiency of 75.6% is obtained.(5)The thermal steady state analysis of the single-stage depressed collector stage and the multi-stage depressed collector was performed using CST software,and the heat distribution of the two collectors was compared.(6)Summarize the work done and plan for the next step.