Ring-bar slow-wave structures for wideband high power TWTs in the millimeter wave range

Several types of ring-bar slow-wave structures are described with wideband high power capability in the millimeter wave region. These include a diamond supported (conventional) ring-bar circuit, a diamond supported double bar connected ring structure and a composite metal ceramic Beryllia ring-bar configuration. The RF-characteristics of these circuits as obtained with cold tests is described, including axial vane-, shield- and dielectric loading effects. Tube designs using these circuits are presented for K-band (18-26 GHz), Ka-band (26-40 GHz), and V-band (40-55 GHz), with corresponding predictions for peak power and thermal capabilities.