Summary

Growth in microwave power generation has been rapid, centering around two types of microwave tubes (see Fig. 29) — the klystron⁴² at X band and the Amplitron² at S band. They are already capable of 200-kW CW and 400-kW CW, respectively. Present high efficiency of the Amplitron (> 70 per cent) is expected eventually to reach 80 to 90 per cent. The efficiency of the klystron is significantly lower (∼50 per cent) with 60 to 70 per cent probably on the way.