A coupled-cavity traveling-wave tube delivering 2 KW CW at 14 GHZ

Summary form only given. Described is a new TWT designed for use in satellite-communications earth stations. This tube delivers more than two kilowatts of carrier power in the 14 to 14.5-GHZ band, with a gain of 32 dB. Because of the high power level and the relatively narrow band (only 3.5% of the center frequency), a "coupled-cavity" slow-wave structure is used. Reducing the pitch of the slow-wave structure on the RF-output side enables obtaining an interaction efficiency of approximately 25%. With a "depressed" collector the overall efficiency exceeds 35%. The internal loads, under vacuum, are made up of siliconcarbide attenuators, brazed to copper. Tests have shown that they can dissipate up to 500 watts. This tube is fully forced-air cooled, with only one blower. The results of two computer programs, one for small-signal operation and one for large-signal operation, are compared to actual measurements made on the TWT.