4.4: Ka-band satellite uplink high-power helix TWTs: Output power evolution at L-3 ETI

To meet the ever increasing demands for high-data rate communications for both broadband commercial and next-generation government satellite uplink applications, L-3 ETI has been actively developing high-power Ka-band helix traveling-wave tubes (TWTs) over the last several years. Since reporting the 8921H, a 250 W CW Ka-band helix TWT, in 2002, L-3 ETI has steadily increased the output power in the Ka-band covering 27.5 to 31 GHz, which currently shows the most user demand, ahead of the higher millimeter-wave bands such as Q-, V-, and W-bands. In 2006, L-3 ETI reported the 8926H demonstrating 400 W CW output power, followed by the 8926HB, a 500 W CW Ka-band helix-TWT (and the 8926HA which is a 500 W Peak / 350 W CW version) reported in 2008, both developed under IR&D funding. In 2008, L-3 ETI launched a customer-funded development program for the 8926HC, a 600 W peak / 450 W CW Ka-band helix TWT covering 30 to 31 GHz and successfully completed the program in 2009. This paper discusses the evolutionary development history of these Ka-band high-power helix TWTs.