Improved flexibility by in-orbit-adjustable saturation output power of TWTs

A substantial number of applications require operation of Travelling Wave Tube Amplifiers (TWTAs) and Microwave Power Modules (MPMs) at saturation to take benefit from the stable RF power and insensitivity to input power variations. Due to the usual end-of-life margins and performance spread over frequency and units the saturation point is typically much higher than really needed for a particular channel. This paper shows how the RF power and therewith the DC power can be optimized for individual MPMs in orbit by telecommand with no change of the saturation characteristics while maintaining RF input power and linearity characteristics. It also shows the typical linearity performance over the adjustment range.