对一种热阴极高功率返波管进行了理论研究，其具有寿命长稳定性好的特点。采用的热阴极发射电流密度为20 A/cm2，发射面积为100 cm2，发射总电流为2 kA。首先对该热阴极单阳极电子枪进行仿真研究，在确保不打火的情况下获得电子枪优化设计参数，再对整管进行粒子模拟研究，仿真结果表明,在工作频率为10.5 GHz时，该热阴极返波管的输出功率可以达到290 MW，换能效率为29%。

A high power backward-wave oscillator (BWO) with a hot cathode is theoretically studied, which has a long life and good stability. Firstly, a single anode electron gun with a hot cathode is simulated by PIC software. The emission current density and the area of the hot cathode are 20 kA/cm2and 100 cm2, respectively. The optimal design parameters of the electron gun are obtained. The PIC simulation results of BWO show that the output power of BWO can reach 290 MW with a frequency of 10.5 GHz, and the beam-wave interaction efficiency is 29%.