A highly efficient, linear, high power X-band coupled cavity TWT for airborne radar

The design and performance of a 5 kW CW X-band coupled cavity TWT, with an ungridded gun, solenoid focused beam, and a five stage depressed collector, is presented. The tube operates over the band 9.2 to 10.2 GHz and demonstrates high efficiency over a large range of RF output power, reaching 50% at 5 kW (excluding solenoid power). At 2 kW, or 4 dB below saturation, the efficiency is 35%. The prime power increases essentially linearly from 2.8 kW for zero output power (DC beam) to 10 kW at 5 kW of RF output.