中文摘要：

采用考虑面电流分布的螺旋带模型计算行波管的冷测参数,基于三维场论模型,通过粒子模拟方法求解空间电荷场的数值解,开发出专业的行波管高频结构互作用代码,计算了一种动态渐变技术（DVT）的C波段超高电子效率行波管,电子效率达到42%,分析其调幅调幅（AM/AM）和调幅调相（AM/PM）的非线性特征,结果与文献报导结果具有很高的一致性,并给出了电子能谱结构和降压收集极分析图,为多级降压收集极的设计提供精确的三维电子轨迹和分析依据。

英文摘要：

We addressed the three-dimensional, nonlinear beam-wave interaction in a traveling wave tube （TWT） with dynamic velocity taper helix. The large signal TWT code was written, based on the three dimensional field model and the numerical space charge field distribution;and the cold test was performed by using the surface current distribution of the taper helix. The nonlinear property of the C-band TWT with the dynamic velocity taper （DVT） technology was charac- terized;and its efficiency was found to be up to 42% by analyzing the AM/AM and AM/PM nonlinear properties. The electronic structures of the spent beam and the precise three-dimensional traces obtained provide the reliable information for the design of the multiple-depressed collector （MDC）.