Enhancing frequency tuning ability of an improved relativistic backward wave oscillator

Frequency agility is necessary for many applications of high power microwave sources. To expand the frequency tuning bandwidth of the BWO with an extracting cavity while holding a high efficiency and a less amplitude fluctuation, a dual-mechanical tuning method by changing the drift length and the cavity length in synchronism is investigated in this paper. A bandwidth of about 750MHz around 9.6GHz with power efficiency over 33% and amplitude fluctuation about -1dB is obtained. The total adjusted length is 24mm. the simulation results demonstrated the frequency tuning ability of the relativistic BWO with multi-gigawatt output power.