X波段高功率相对论速调管放大器研究

为进一步提高X波段相对论速调管放大器的输出功率，采用理论分析与粒子模拟的方法对双群聚腔级联式相对论速调管放大器进行了研究。分析了提高注入腔对注入微波吸收效率的方法，分析了群聚腔调制能力与腔体模式、Q值等参数的关系，分析了输出腔提取效率与Q值的关系。在三维粒子仿真中，设计了模式反射器抑制TEM模式泄露与杂模振荡，得到了功率超过2.5 GW，频谱纯净，频率锁定为8.40 GHz，输出输入微波相位差稳定，抖动不超过2°的高功率微波输出。

Research of X-band high power triaxial klystron amplifier

To achieve GW-level amplification output radiation at X-band, a relativistic triaxial klystron amplifier （TKA） with two-stage cascaded double-gap bunching cavities is investigated. The input cavity is optimized to obtain a high absorption rate of the external injection microwave. The cascaded bunching cavities are optimized to achieve a high depth of the fundamental harmonic current. A double-gap standing wave extractor is designed to improve the beam wave conversion efficiency. Two reflectors with high reflection coefficients both to the asymmetric mode and the TEM mode are employed to suppress the asymmetric mode competition and TEM mode microwave leakage. Particle-in-cell simulation results show that a high power microwave with a power of 2.53 GW and a frequency of 8.4 GHz is generated with a 690 kV, 9.3 kA electron beam excitation and a 25 kW radio-frequency signal injection. Meanwhile, there is insignificant self-excitation of parasitic mode in the proposed structure by adopting the reflectors. The relative phase difference between the injected signals and the output microwaves keeps locked after the amplifier became saturated.