Optimization of Phase Nonlinear Characteristics of Folded Waveguide Traveling-Wave Tube

When millimeter wave folded waveguide (FWG) traveling wave tube (TWT) operates near saturation, it is usually accompanied by some nonlinear phenomena. These nonlinear distortions generated in the process of beam-wave interaction will lead to phenomena such as phase distortion, which will reduce the output performance of FWG TWT and seriously affect the overall performance of the communication system. In this paper, a genetic algorithm is introduced to optimize the phase nonlinearity (AM/PM) of the FWG TWT, and an E-band FWG TWT is used as an example. Finally, the optimization results are given. The results show that the AM/PM conversion coefficient of the FWG TWT is reduced by 88.9% and the efficiency is improved by 36.6% at the optimum frequency point. In addition, the AM/PM in the bandwidth is reduced by more than 16% and the efficiency is also improved by more than 21.8%. These optimization results indicate that the use of genetic algorithm can provisionally guide the AM/PM structure optimization design of FWG TWT.