Numerical Studies on a Novel Coaxial Single-Pass Superradiance Relativistic Backward-Wave Oscillator

In this paper, a novel coaxial single-pass superradiance relativistic backward-wave oscillator (SR-RBWO) is proposed and studied by simulation. In the proposed SR-RBWO, a coaxial structure is used in the beam-wave interaction region. The outer conductor is a corrugated waveguide, and the inner conductor is hollow inside and forms a circular waveguide. The circular waveguide is then used as the output waveguide. Instead of being reflected, microwaves will be coupled to the output waveguide by the coupling hole at the electron-injector (left) end. Cutoff neck is not required. Strongly nonuniform corrugation depth is used near the collector edge to increase the power-conversion efficiency. For an electron beam having a 3.25-GW power in 4.9-ns pulse, in the proposed SR-RBWO with optimized parameters, the SR pulses of a 7-GW power and 450-ps pulse duration are obtained by simulation at an 8.2-GHz center frequency that corresponds to the power-conversion efficiency of 215%. The applied magnetic field is about 2.7 T.