Linear Dispersion Relation of Double Period Slow Wave Structure for High-Power Backward Wave Oscillators

Abstract

Linear dispersion relation for an axisymmetric metal-wall slow wave structure (SWS) with double period corrugations has been analyzed numerically. The double period SWS is here proposed for improving the oscillation frequency performance of high-power backward wave oscillators that may sustain stable oscillation despite the energy exhaustion of the driving electron beam from upstream to downstream in the SWS. It is shown that conventional TM 01 mode in a single period SWS is split into a number of isolated branches. Oscillation frequencies are kept comparatively unchanged rather than the case of single period SWS.