100 W 18-40 GHz traveling wave tube

This paper summarizes the deisgn and performance of the first helix type, periodic permanent magnet focused traveling wave tube to generate 100 W of CW power over one octave at frequencies up to 40 GHz. Key features of the design include a Pierce gun, a two-stage collector, WRD-180 input and output waveguides, and a thermally rugged brazed circuit design whose broadband characteristics arise from uniquely shaped helix support rods. Design highlights and performance data are presented.