Design and study of slow wave structure of the THz folded waveguide TWT over 60W

Abstract In this paper, the equivalent circuit method is used to analyze the dispersion characteristics of the folded waveguide and calculate the coupling impedance. The influence of the surface roughness and conductivity of the waveguide on the loss of the high frequency circuit is considered. In order to improve the efficiency of the beam wave interaction, the two kinds of slow wave structures of the folded waveguide TWT are designed by using the variable period technology. The three-dimensional electromagnetic software Microwave Tube Simulation Software (MTSS) is used to simulate the beam wave interaction of TWT. After optimization, the output power of both structures is over 60W, the electronic efficiency is more than 5.5%and the gain is greater than 32dB in the 211GHz-221GHz frequency range.