LINEAR DISPERSION-RELATION OF DOUBLE PERIOD SLOW-WAVE STRUCTURE FOR HIGH-POWER BACKWARD-WAVE OSCILLATORS

Linear dispersion relation for an axisymmetric metal-wall slow wave st ructure (SWS) with double period corrugations has been analyzed numeri cally. The double period SWS is here proposed for improving the oscill ation frequency performance of high-power backward wave oscillators th at may sustain stable oscillation despite the energy exhaustion of the driving electron beam from upstream to downstream in the SWS. It is s hown that conventional TM(01) mode in a single period SWS is split int o a number of isolated branches. Oscillation frequencies are kept comp aratively unchanged rather than the case of single period SWS.