Design Of Sheet Beam Gun And Particle-In-Cell Simulation Of The Meander-Line Traveling Wave Tube

In order to meet the demand of wide band, high gain, low cost and simple production in the band of millimeter and terahertz, miniaturization and complanation are the trend of the development of travelling wave tube (TWT). Because of the focusing and laminar flow property of the sheet beam are very great, the study on the sheet beam as source of the TWT is very popular. This paper focuses on the design of planar elliptical sheet beam gun, the cold characteristics of the slow wave structure (SWS) and the particle-in-cell simulation of meander-line TWT. The influence of the electromagnetic band-gap (EBG) on the performance of the TWT is also investigated to improve the efficiency of the planar TWT.The second chapter mainly focused on the theoretical modeling and simulation of the planner elliptical sheet beam gun. The detailed process of the electron gun design was proposed. The influence of the structure parameters on the performance of the electron gun was also simulated using CST. The optimized gun meet the requirements of the TWT.In the third chapter the model of a SWS was established, and the dispersion, coupling impedance and transmission characteristics of the SWS were simulated and analyzed.The influence of the PEC substrate and the EBG substrate on the cold parameters of the SWS were compared. Meanwhile, the effect of the boundary conditions and the position of the integral line on the cold parameters of the SWS were discussed.Finally, the PIC simulation of the whole TWT was carried out in the CST wave studio, and the post-processed results were analyzed. Moreover, the sweep frequency characteristics, the relationship between input and output power and the influence of SWS length on the output power were studied.