Efficiency enhancement of RBWO by introduction of coaxial rippled inner conductor

Relativistic backward wave oscillator (RBWO) with the rippled inner conductor is proved to be the highly efficient high power microwave (HPM) source device. This paper investigates operation characteristics of this device by comparing it with hollow RBWO to depict its inherent merits leading to the high efficiency. It is found that introduction of the inner conductor can promote the beam quality. The distribution of the synchronous wave in coaxial slow wave structure (SWS) benefits the wave-beam interaction. The electron dump on the inner conductor ensures the wave-beam interaction efficiently till the electron is collected by the inner conductor.