主要介绍了某X波段大功率耦合腔脉冲行波管两级降压收集极的CAD分析、结构设计及研制结果。通过使用国营第七七二厂2.5维互作用程序软件包(TWTC软件)对行波管输出端96条电子轨迹的半径，轴向、径向速度模拟并分析，判断电子注层流性情况，然后对两级降压收集极进行光学设计、结构设计和热分析，装管验证结果表明：实测值结果与理论计算的两级降压收集极各电极电流分配比例、收集极效率等参数接近。

This paper presents a method for design a suitable two stage depressed collector of X band large duty ratio coupled-cavity traveling wave tube (CC-TWT). The axial, radial velocities and radius of 96 electron trajectories in the output potion of this TWT were simulated and analyzed by 2.5 dimensional interaction package owned by 772nd factory. A refocusing segment was designed to improve the flow of electron injection layer with the help of re-simulation of these parameters. Then a two stage depressed collector was designed with optical design, structural design and thermal analysis. Finally, a TWT was assembled for testing. The measured proportion of the current distribution in every collector electrode and the collector efficiency are close to the analytical full-band average results, which means that this analytical method is suitable for design of two stage depressed collector for high-power CC-TWT.