Design and Optimization of Axis-Adjustable Multistage Depressed Collector for 0.22-THz Traveling Wave Tubes

For the efficient optimization of a multistage depressed collector (MDC), an axis-adjustable MDC optimized using the genetic algorithm (GA) is presented in this article. The optimization processes are realized with a reasonable balance between the collector recovery efficiency and electron reflux rate by modifying the fitness function of GA. Through the proposed method, the best recovery efficiency 88.5% and 0.72% electron reflux rate of MDC are obtained, and a three-stage symmetric collector has been designed with the GA optimization and fabricated, for a 0.22-THz TWT. The experimental results are in well agreement with that of simulations, which indicates that the methods we propose would be beneficial to the design of high efficiency of TWT.