Mode selection in overmoded relativistic backward-wave oscillator

A high order mode operation mechanism in an overmoded relativistic backward wave oscillator (RBWO) is presented to increase the power handling capacity of device. In the numerical simulation, the generation of the microwave pulse with the output power 425 MW and conversion efficiency 32% is achieved at 60.5 GHz with the external magnetic field of 1.25 T, and the operation mode is TM03 mode. Besides, the RBWO of TM03 mode provides larger power handling capacity than that operating in TM01 mode.