A dual-frequency coaxial relativistic backward-wave oscillator with a modulating resonant reflector

An X-band dual-frequency coaxial relativistic backward-wave oscillator with a modulating resonant reflector is presented and investigated in this paper. Through a theoretical study, numerical analysis and particle-in-cell (PIC) simulation, the stationary single-frequency regime is selected as the operation regime, and the high-frequency characteristics of the system, including the unstable beam-wave interaction regions and operation mode of each section, are obtained. The PIC simulation results indicate that an average power of 1.07 GW with a power conversion efficiency of 24.2% is obtained with an electron beam of 520 kV and 8.5 kA guided by an axial magnetic field of 2.4 T, and the two dominant frequencies are 9.43 and 10.30 GHz, respectively. Furthermore, a periodic-like change in the smaller dominant frequency with a frequency agility bandwidth of about 0.40 GHz is acquired.