Simulation of a low magnetic field relativistic backward wave oscillator with single mode structure

A low magnetic field relativistic backward wave oscillator with single mode structure is presented. Particle-in-cell simulation results show that 1.25GW output power with 37% efficiency is generated under 0.88 T. The mode purity of the output signal is high because higher modes are cut off by the structure. According to the analytical results, the influence of bombardment of electrons on the surface of the slow wave structures is minor. A modulation cavity is adopted to enhance beam-wave interaction and realize mechanical frequency tunability. The power capacity is increased though redistribution of electric field. The computational results indicate that the device with a single mode structure is a competitive candidate for devices working at low magnetic field especially for devices focused with permanent magnet. (C) 2016 AIP Publishing LLC.