设计了一种能在C波段和X波段实现稳定双频输出的带有非对称谐振反射腔的单电子束同轴相对论返波振荡器。采用耦合阻抗跃变型慢波结构, 使用粒子PIC模拟软件进行了粒子模拟研究。模拟结果显示: 轴向电场在系统中的分布得到改进, 电子束的能散得到改善。在电子束电压511 kV, 电流8.95 kA, 引导磁场0.73 T的条件下, 双频器件实现了8.09 GHz和9.91 GHz的双波段频率稳定输出, 平均功率为1.0 GW, 波束互作用效率为21.9%, 效率高于空心双波段返波管及其他双波段器件。器件辐射功率的拍频为1.82 GHz, 拍波更为明显和稳定。模拟研究中同时发现, 随着慢波结构之间漂移段的变化, 双频频率都呈现一种准周期的变化。

A C-band and X-band dual-frequency coaxial relativistic backward-wave oscillator (CRBWO) with an asymmetric resonant reflector and a single annular electron beam is designed and investigated in this paper. The improved slow wave structure (SWS) with stepwise variable coupling impedance is employed, and the particle-in-cell (PIC) simulation code is used to investigate the device, which indicates that the axial electric field in the SWS is enhanced and the energy scatter of the relativistic electron beam (REB) is improved. The PIC simulation results show that with an electron beam of 511 kV and 8.95 kA and an axial magnetic field of 0.73 T, an average power of 1.0 GW with power conversion efficiency of 21.9% is obtained and the two dominant frequencies are 8.09 GHz and 9.91 GHz, respectively. The efficiency is higher than dual-band non-coaxial RBWO and other dual-band high-power microwave (HPM) generators. A more clear and stable beating radiation microwave power with beating frequency of 1.82 GHz is acquired, and the dual frequencies both demonstrate periodic-like dependence on the length of the tapered waveguide between the two SWS sections.