S波段长脉冲相对论返波振荡器实验研究

Experimental investigation of an S-band long-pulse relativistic backward-wave oscillator

从物理机制上定性地分析了导致脉冲缩短的主要原因,给出了长脉冲重复频率运行下的相对论返波振荡器(RBWO)设计原则。结合传统谐振式返波振荡器的基本设计理论,设计和模拟优化了工作在S波段的长脉冲RBWO,并利用本实验室现有长脉冲脉冲功率驱动源开展了S波段长脉冲RBWO的实验研究。实验结果表明:在单次运行条件下,微波输出功率达到约2 GW、脉宽约90 ns;在10 Hz重复频率运行条件下,输出微波功率达到约1 GW、脉宽约100 ns。器件产生的微波频率为3.6 GHz,输出模式为TM01模,效率约20%。对实验结果分析表明,器件截止颈和第一个慢波结构结合处的爆炸发射是导致脉冲缩短的主要原因之一。

The main reasons of causing pulse-shortening in high power microwave devices are qualitatively analyzed.Some important rules for designing a long-pulse relativistic backward-wave oscillator（RBWO） are given.According to the above rules and the basic theory of resonant RBWO,an S-band long-pulse RBWO is designed and investigated both numerically and experimentally.Experimental results show that a 2 GW microwave with pulse duration of 90 ns at single shot mode and 1 GW microwaves with pulse duration of 100 ns at 10 Hz repetition rate mode are obtained.The microwave frequency is 3.6 GHz with dominant mode of TM01,and power conversion efficiency is about 20%.The explosive electron emission in intense RF field between the cut-off neck and the first slow-wave structure（SWS） is one of the main causes leading to the earlier unexpected termination of microwave output.