中文摘要：

利用粒子模拟技术对Ka波段耦合腔行波管的非线性互作用现象进行了研究。互作用电路采用的是重入式双交错梯形线耦合腔慢波结构，设计了匹配良好的高频耦合系统，并建立了一个基于CPI的Ka波段耦合腔行波管的三维电路模型。粒子模拟结果表明，当采用和CPI管子相同的电气参数和色散特性时，该管能在28.3～30 GHz的频率范围内有大于550 W的饱和平均输出功率，瞬时带宽大于600 MHz，相应的饱和增益和电子效率分别大于33 dB和8.39%。上述结果与CPI的测试结果吻合良好，证明了设计方案的可行性以及粒子模拟能较准确地对耦合腔行波管的工作性能进行估计。

英文摘要：

The particle-in-cell simulations of a Ka-band coupled-cavity traveling-wave tube （CCTWT） were performed to investigate the nonlinear interaction of the tube. The interaction circuit employs the double staggered ladder line coupled-cavity slow-wave structure. Combined with the design of well-matched high frequency coupling system, a 3-D circuit model based on CPI’s Ka-band CCTWT was constructed. The particle-in-cell simulation results show that the tube can produce saturated average output power over 550 watts with greater than 600 MHz instantaneous bandwidth ranging from 28.3 GHz to 30 GHz when we adopt the similar parameters as CPI’s Ka-band CCTWT, such as beam voltage, beam current and the slow-wave structure dispersion characteristics. The corresponding saturated gain and beam efficiency can reach over 33 dB and 8.39%, respectively. These results are in good agreement with the experimentally measured ones of the CPI’s Ka-band CCTWT, which suggest that our design scheme is feasible and the CST PIC solver can accurately predict the performance of the CCTWT.