Development of a medium power L-band traveling-wave amplifier

The development and performance of a high gain medium power traveling-wave amplifier are described. Powers up to 7 watts at 15 per cent efficiency have been achieved. The small signal gain approaches 50 db in the middle of the band, and exceeds 35 db over a 2 to 1 range of frequencies. The tube itself consists of a glass-supported helix with a metal shell at one end housing the cathode structure, and a copper collector at the other end. The input and output couplings are made by means of coupled helices which are mounted in a brass tube or matching structure which is external to the vacuum envelope. The matching structure is supported in the focusing solenoid.