Novel SWS designs for high power Ka-band TWTs

Novel wide-band slow-wave structures (SWSs) with decreased periodicity are proposed for application in high frequency, high power TWTs. Prototypes of helix circuits with turns connected by `zigzag' lines or by a periodic row of rings connected in the longitudinal direction were fabricated and their dispersion characteristics were measured and compared. Advantages of these circuits over conventional helices are described.