中文摘要：

为实现高功率微波的相干功率合成，开展了S波段高增益相对论速调管放大器输出微波相位特性的粒子模拟和实验研究，粒子模拟与实验结果均表明电子回流是影响输出微波相位特性的主要因素．在有效控制电子回流的情况下，实验实现输出微波相位抖动小于±10°，锁相时间达90ns．以此计算，若相位抖动在±10°内满足均匀分布，十台该高增益相对论速调管放大器的功率合成效率将大于99％．

英文摘要：

In order to realize the combination of the coherent high power microwave, an 5=band high gain relativistic zlystron amplifier with high phase stability is presented and studied theoretically and experimentally. The phase characteristics of the output microwave are explored in particle-in-cell code and experiment. The experimental results accord well with the simulation results, which indicates that the parasitic oscillation excited by retrograde electrons is the main cause of phase variation in the development of high-gain relativistic klystron with high phase stability. When the input RF power is 10 kW, a microwave pulse with about =t=10~ in relative phase difference fluctuation between output and input is obtained in experiment. And the corresponding locking duration is about 90 ns. Accordingly, the expectation of power combination efficiency of 10 high-gain relativistic klystron amplifiers can be achieved to be 99% with continuous uniform distribution of random relative phase difference.