Particle simulation of coaxial multi-frequency relativistic backward wave oscillator

The dual-electron beam coaxial relativistic backward wave oscillator(RBWO) was firstly put forward to produce dual frequency microwave output. The properties of the RBWO we investigated with a 2.5-dimensional relativistic fully electromagnetic PIC software. The results show that, for annular relativistic electron beam with voltage of 625 kV, current of 24 kA and guided magnetic field of 0.772 T, the device can produce stable dual-frequency microwave output. The frequencies are 11.5 and 12.2 GHz the average power is about 1.15 GW and the average power efficiency is 7.7%. Three frequency microwave was obtained by changing the cycle number, and the results we discussed．