High efficiency linear C-band helix traveling wave tube

Summary form only given. This paper describes the development and performance of a C-band helix traveling wave tube. A new high efficiency collector was developed that employs elaborate electrode processing to reduce the secondary electron emission ratio, advanced asymmetrical electrode geometry, transverse magnetic flux threading and a short refocusing section. Fewer secondary electrons are generated and more electrons stay in the collector, reducing helix or body current. Limiting input drive so the power output stays within the linear operating range of the TWT and avoids the near saturation region reduces both the spread and the mean of the velocity distribution in the electron beam. Capturing this beam with the new high efficiency collector mentioned above has enabled higher levels of collector depression than have been previously obtainable. The result is a TWT that is more efficient, is easier to cool and has lower annual operating energy costs.