Large Signal 1-D Rapid Beam-wave Interaction Simulation of Sheet Electron Beam Traveling Wave Tubes

keywords:traveling wave tubes  beam-wave interaction  sheet electron beam  space charge field  rapid computation program

Abstract:Calculating the electron beam-wave interaction characteristics of traveling wave tubes ( TWTs) is a crucial step in designing process. However, particle in cell (PIC) methods that solve Maxwell′s equations using divided mesh grids are memoryintensive and time-consuming, leading to low efficiency in TWT development. In this paper, taking a sheet electron beam TWT as an example, this paper derive the space charge theory for a rectangular electron disk. By combining this with the electron motion equations and the excitation field equations, this paper establishes a one-dimensional frequency domain theory for the beam-wave interaction in sheet electron beam TWTs. By developing a program to solve the beam-wave interaction equations, this paper can quickly obtain results. This theory simplifies the beam-wave interaction system by neglecting the transverse motion of electrons and making certain approximations, thereby achieving accurate and rapid computation. The efficiency and reliability of the fast computation program are validated by comparing its results with those from 3D full-wave electromagnetic simulation software and experimental data from a G-band TWT.