A 20 watt 22.5 GHz mini-tube

There is an increasing need for helix traveling wave tubes above 18 GHz capable of high volume production, for various military and commercial systems. This paper describes the design and performance of such a tube which produces greater than 20 Watts of K-band CW power at a small signal gain level of 65 dB. Size, particularly length, has been minimized by achievement of a low-voltage, high-perveance design. A low-noise minimum-volume power supply has been developed for this tube. The measured noise floor using a 100 Hz wave analyzer filter bandwidth is greater than 100 dB below the carrier, and inverter spurious lines are typically 65 dB or more below the carrier.