Experimental Study of Oversized Backward Wave Oscillator with Coaxial Slow-Wave Structure

Abstract

Studies of coaxial oversized backward wave oscillators (BWOs) are reported. The beam voltage is weakly relativistic (less than 100 kV). The slow-wave structure consists of a periodically corrugated oversized waveguide and periodically corrugated inner conductor, whose target operating frequency due to Cherenkov interaction is in the K-band. A starting energy exists for the coaxial oversized BWO as it does for a hollow oversized BWO. The coaxial slow-wave structure has two surface wave modes caused by the inner and outer corrugations. Operation based on these surface modes can be controlled by the beam diameter. The phase difference between the inner and outer corrugations has little effect on operation of the oversized BWO.

Experimental Study on Backward Wave Oscillators Using Dielectric Discharge Cold Cathodes

“…Recently, high-power microwave sources with small sizes and variable frequencies are desired for plasma heating in nuclear fusion processes, radars, communication systems, measuring systems, and medical equipment. One such microwave source is the backward wave oscillator (BWO) [1][2][3][4][5]. A cold cathode, used inside the BWO, does not need to be heated by a power supply, thereby enabling miniaturization.…”