通过波导功率合成手段提高输出功率,在微波工程领域已得到广泛应用,随之合成功率的增加微波功率合成器设计难度相应提高。因此,设计了一种基于过模结构80 k W的微波功率合成器。针对大功率容易造成功率合成器内部场强击穿的问题,采用过模结构增加了合成器的截面积以降低内部最大场强,从而增加了功率容量。功率合成器由两个匹配后的魔T作为第一级合成,然后采用过模波导结构作为第二级合成,设计的大功率合成器的工作频率在2 450±15 MHz,路间隔离达-20 d B以下,内部最大场强为2.73e+5 V/m,合成效率达到了99.0%。
为满足工业应用大功率微波源的需求,开展了基于两路S波段1 k W注入锁定连续波磁控管的微波功率相干功率合成系统的实验研究。在理论上,分析了两路磁控管输出微波功率比和相位差对合成效率的影响。在实验中,用同步的微波源实现两路注入信号,采用磁控管注入锁定技术,通过虚拟仪器软件实现了自动化合成功率控制。实验成功进行了基于两路1 k W在S波段注入锁定连续波磁控管的相干功率合成。测试结果表明,两路S波段1 k W连续波磁控管的相干功率最高合成效率≥95%,为研究高效率的大功率合成微波源提供了重要的实验基础。
A side band power re-injection locked （SBPRIL） magnetron is presented in this paper. A tuning stub is placed between the external injection locked （EIL） magnetron and the circulator. Side band power of the EIL magnetron is reflected back to the magnetron. The reflected side band power is reused and pulled back to the central frequency. A phase-locking model is developed from circuit theory to explain the process of reuse of side band power in SBPRIL magnetron. Theoretical analysis proves that the side band power is pulled back to the central frequency of the SBPRIL magnetron, then the amplitude of the RF voltage increases and the phase noise performance is improved. Particle-in-cell （PIC） simulation of a 10-vane continuous wave （CW） magnetron model is presented. Computer simulation predicts that the frequency spectrum＇s peak of the SBPRIL magnetron has an increase of 3.25 dB compared with the free running magnetron. The phase noise performance at the side band offset reduces 12.05 dB for the SBPRIL magnetron. Besides, the SBPRIL magnetron experiment is presented. Experimental results show that the spectrum peak rises by 14.29% for SBPRIL magnetron compared with the free running magnetron. The phase noise reduces more than 25 dB at 45-kHz offset compared with the free running magnetron.
