Results of the Development of a 700 W 12 GHZ TWT for Direct TV Broadcasting Satellites

The paper describes the first phase of the development of a satellite TWT with an output power of P2 = 700 W. Design considerations for more than 7 years life are presented. The concept of the tube with coupled cavity, self-radiating 5 stage collector and SmC05 - magnets will be described. The first step before tapering the delay line was to optimise a uniform delay line. Remarkable results were obtained with a uniform delay line and single collector depression. a) Efficiency 39 % at 2,5 °/dB am-pm conversion b) Efficiency 32 % at 0 °/dB am-pm conversion and ± 3° phaseshift only by changing the input power from zero to full saturated drive. These results are in much better agreement with the results of theoretical computations as the measured characteristics of helix TWT so far.