Research On Design And Simulation Technology Of Power Transmission Structure Of Microwave Tubes

Travelling wave tube has a wide frequency band and high power and gain,and is widely used in satellite communications,electronic countermeasures,radar and other systems.The input and output structure,as an indispensable part of the traveling wave tube,is particularly important for its research.In the working process of the traveling wave tube,how the high frequency signal outside the tube can enter the slow wave structure without reflection,which involves the design of the energy transmission structure.With the advancement and rapid development of computer-aided design technology,the use of three-dimensional electromagnetic simulation software to design vacuum devices has become an important method.This paper uses CST MWS and microwave tube simulation software package MTSS to simulate the input and output structure of a power synthesis V-band foldedband traveling wave tube and Ku-band ultra-wideband helix traveling wave tube.The main work and innovation are as follows:1.As the frequency increases,the size of the traveling wave tube decreases and the power capacity decreases.The use of multiple traveling wave tubes for power integration is an effective measure to increase the output power.Aiming at the 57.5-61.5GHz folded waveguide traveling wave tube,this paper analyzes and designs the corresponding energy transmission structure.In the working frequency band,the standing wave ratio of the entire energy transmission system is less than 1.65,and the reflection performance is good.2.Broadband helix traveling wave tubes are widely used in many fields such as satellite communications and radar.The thesis carried out the design of the energy transmission structure for the 12-18 GHz helix traveling wave tube.The modeling and simulation calculation of the energy transmission system are completed by using CST MWS.A multi-section coaxial impedance converter and a coaxial-rectangular waveguide converter are designed,and the influence of key structural parameters on the transmission characteristics of the entire tube is studied.In the end,the standing wave ratio of the energy transmission system is less than 1.60 in the working frequency band.3.To realize the precise design of the energy transmission structure of the helix traveling wave tube,it is necessary to consider the influence of the electron beam during the operation of the traveling wave tube.The paper presents a simulation design method for the thermal matching characteristics of the input and output structure of the helix traveling wave tube and the slow wave system.This method uses a special electromagnetic medium for electron injection to be equivalent.From the perspective of beam-wave interaction,the introduction of electron beams and space charge fields shifts the high-frequency dispersion characteristics of electromagnetic waves in the slow-wave structure,which shifts the dispersion of the thermal cavity(center frequency)to the normalization of the initial electron velocity.Value to determine the electromagnetic characteristics of this equivalent medium.The effect of the addition of the equivalent electron beam of this special medium on the electromagnetic wave transmission in the slow-wave structure is used to realize the simulation of the reflection characteristics of the energy transmission port of the helix traveling wave tube in the state of the hot electron beam.4.In the actual processing process,the success or failure of the sealing of the energy transmission window has a great influence on the performance of the entire tube.The thermal stress coupling analysis is carried out on the energy transmission window of the traveling wave tube.Using ANSYS workbench 17.0,a thermodynamic simulation of the welding of the ceramic window and the energy transfer pin was carried out,and the thermal stress of the seal was analyzed.Combined with the software simulation results,the success or failure of the sealing and the reliability of the ceramic window were studied.The input and output structure of the traveling wave tube is an important part of the traveling wave tube.The thesis focuses on the high-band power integrated folded waveguide traveling wave tube and broadband helix traveling wave tube,carried out the simulation design of the energy transmission structure,and proposed a simulation method for the thermal matching characteristics of the helix traveling wave tube energy transmission structure and the slow wave system.It provides a reference for the design and development of the traveling wave tube energy transmission system.