Research On High-efficiency Interaction Technology Of Staggered Double Vane Sheet Beam Traveling Wave Tube

Millimeter wave technology has extremely important applications in 5G communications,weapon guidance,vehicle radar,security inspection,and electronic countermeasures.Vacuum devices have been playing an irreplaceable role in the highfrequency field due to their advantages of high power,high efficiency,high reliability and long service life.As one of the important vacuum millimeter wave sources,the sheet beam traveling wave tube with broadband characteristics has very important study and application value.The sheet beam device is developed from the traditional round beam device.The expansion of the round electron beam to the sheet electron beam increases the current of the electron beam at the same current density,which helps to increase the output power of the sheet beam device.The flat belt structure of the electron beam is very suitable for the periodic cusped magnetic focusing system,which is very beneficial to reduce the volume and weight of the whole tube,and realize the miniaturization and portability of the device.As a place where the electron beam interacts with the high-frequency field to exchange energy,the staggered double-vane slow-wave structure is composed of an allmetal structure.The relatively strong heat dissipation capability allows the device to withstand a larger power capacity.Its structure is relatively simple,which is very suitable for sheet beam transmission,and has natural advantages in mechanical processing and device assembly.This thesis mainly studies the realization of the highefficiency interaction technology of the staggered double-vane sheet beam traveling wave tube,and deeply analyzes the bunching behavior of the electron beam and the energy conversion process of the electron beam and the high frequency field in the sheet beam traveling wave tube.On this basis,the optimization method of all-period multiparameter phase velocity tapering is improved and perfected,the efficiency of beamwave interaction of the sheet beam traveling wave tube is further improved,and the output power is increased.The research content of this thesis is as follows:1.For the all-period multi-parameter phase velocity tapering optimization scheme,the influence of different numerical optimization methods on the optimization results is studied,and the best optimization algorithm is selected based on the convergence speed and the global optimal value.The experimental results show that the particle swarm algorithm has obvious advantages than others;2.In Ka-band,using the all-period multi-parameter phase velocity tapering optimization scheme to explore the limit of the beam-wave interaction efficiency of the sheet beam traveling-wave tube,after multiple optimization experiments,the slow-wave structure with 64.5 % beam-wave interaction efficiency was obtained in the CST Studio particle in cell simulation verification;3.The combination of multi-objective optimization and all-period phase velocity tapering optimization is adopted to improve the efficiency of beam-wave interaction in the entire bandwidth,and give full play to the advantages of the wide frequency bandwidth of the sheet beam traveling wave tube;4.For the slow-wave structure with attenuator,the 1-D nonlinear beam-wave interaction code is improved,and the all-period phase velocity tapering scheme is applied to improve the beam-wave interaction efficiency considering the attenuator;5.In order to solve the calculation error of the 1-D nonlinear beam-wave interaction code,the Matlab-CST Studio joint simulation optimization scheme is adopted,and it is applied in the design of the X-band slow-wave structure.