A Modified Sinusoidal SWS with Dominant TM01 Mode and Improved Interaction Impedance for Use in BWOs

Abstract

A modified sinusoidal slow wave structure with a dominant TM01 mode which is the main interaction mode for a backward wave oscillator is proposed. The TM01 mode dominance is achieved by introducing circular discs along the circumferential ends of the conventional sinusoidal SWS. SWS designs for individual control of TM01 and TE11 mode cut-off frequencies are proposed. This SWS is also capable of coupling with a higher phase velocity as compared with the conventional sinusoidal SWS and exhibits improved interaction impedance characteristics which make them ideal candidates for use in backward wave oscillators.