2.5 Watt, X-band traveling-wave tube for the COMSAT program

This paper will present the work accomplished on a 2.5 watt, ppm-focused, cw, X-band traveling-wave tube amplifier for satellite communication applications. Because of the tube´s application, efficiency, reliability, life, weight, and size are of extreme importance in the design. This tube is being developed, produced, and life tested as part of the COMSAT program. The presentation will include theoretical as well as experimental results on the program. The theory will be concerned with the philosophy in designing an ultra-long life and highly efficient device. Parameters such as focusing field, cathode loading, beam perveance, space-charge, and normalized beam radius, γr0, will be discussed briefly in their inter-relationship in the design. The experimental results will present detailed characteristics of the tube such as power output, gain, efficiency, noise figure, phase and distortion. Unique constructional details, such as use of ultra-clean assembly areas for tube fabrication, to insure long life and high reliability will also be presented. Finally, the life test program that these tubes will undergo will be discussed.