D波段行波管三级降压收集极的设计

效率是行波管(TWT)的重要技术指标，为提高某一0.22 THz折叠波导行波管的效率，需设计多级降压收集极。对注波互作用后的电子注信息进行分析，估算收集极效率最高时的电压设置。利用电磁仿真软件对三级降压收集极电极结构和电压设置进行仿真优化，得到效率大于87.5%，回流电流小于0.328 9 mA的轴对称三级降压收集极；在第二电极入口采用斜口结构进行仿真优化，得到回流电流小于0.075 mA的非轴对称三级降压收集极。结果表明，采用斜口结构可以有效降低0.22 THz行波管多级降压收集极的回流电流。

Design of three-stage depressed collector for D-band TWT

Efficiency is one of the important technical parameters of Traveling Wave Tube(TWT). In order to improve the efficiency of a 0.22 THz folded waveguide TWT, it is necessary to design a multistage depressed collector. Firstly, the spent-electron-beam characteristics in the collector entrance are analyzed, and the voltage settings at the highest collection efficiency are predicted. Then the structure and voltage settings of the three-stage depressed collector are optimized by electromagnetic simulation software. The axisymmetric three-stage depressed collector with collector efficiency greater than 87.5% and back streaming current less than 0.328 9 mA is obtained. Finally, an asymmetric three-stage depressed collector with a back streaming current less than 0.075 mA is obtained by using an oblique structure at the entrance of the second electrode. The results show that the back streaming current of 0.22 THz TWT multistage depressed collector can be effectively reduced by using the oblique structure.