DEVELOPMENT OF A 0.5 TO 2.1 GHZ LOW NOISE TRAVELING-WAVE TUBE AMPLIFIER

The purpose of this program is the attainment of low-noise amplification over two octaves in a single traveling-wave tube. Noise figure is to be less than 6.5 dB from 0.5 to 2.1 GHz with a minimum of three milliwatts saturated power output. The work described herein has been aimed primarily at raising the power output to the required three milliwatt level and achieving uniform gain over the full band. This has been sought through the use of a servered helix, with the output section operating with higher voltage and lower gamma than the input, or low-noise section. Good results have been obtained with this method, the power output being greater than two milliwatts over practically the entire band. It is concluded that this approach is entirely feasible technically, and that future effort will be expended applying it to reduce gain variation at an increased power level. At present, noise figure of the tube is within the specification over all of the band. (Author)