Advances in space TWT efficiencies

Overall dc-to-rf conversion efficiency continues to be the single most sign ificant figure of merit for commercial space traveling wave tube amplifiers (TWTAs). Improvements in TWTA efficiency immediately translate into potent ial revenue increases for satellite operators, since additional transponder s can he carried on board the spacecraft for the same prime power and waste heat handling capacity. The revenue implications of increased efficiency h ave spurred TWT manufacturers to continue wringing out every possible incre ase in efficiency. By optimizing both rf circuit and collector designs, ove rall efficiencies >70% have now become routine. This paper will discuss the results of several experiments to improve TWT efficiency demonstrating how these impressive efficiencies may be achieved.