Experimental study of backward wave oscillator with resonant reflector operating at low magnetic field

This paper presents the results from simulative and experimental studies of backward wave oscillator(BWO) with resonant reflector operating at low magnetic field. The influence of drift tube length between the resonant reflector and the slow wave structure on the efficiency of the BWO is studied. Simulation and experimental results indicate that because of the pre-modulation effect of resonant reflector, there are several efficiency spikes at optimum drift lengths. When the applied magnetic field was 0.7 T and the drift length was 4.9 cm in the experiment, the microwave power of 700 MW with 8.7 GHz frequency and 20 ns pulse width was obtained.