A wide band high power "Long Slot" traveling wave tube

This paper describes a traveling wave tube designed to give 1 MW of output power over 20% bandwidth in S-band. The slow wave structure used was the "Long Slot" invented at Stanford University. Methods of preventing the structure from oscillating in unwanted modes were devised and measurements of gain and efficiency bandwidths were made on a stable severed tube. A tube having a maximum gain of 40 dB had a 3 dB saturated efficiency bandwidth of 19%. The maximum efficiency obtained was 30% at a beam voltage of 120 kV (microperveance of 1.6). Good agreement was found between the theoretical small signal gain calculated using a computer program combining R. L. Pease\´s klystron type theory with Curnow\´s equivalent circuit theory, and the gain actually obtained.