TRAVELING-WAVE TUBE FOR COMMUNICATION SATELLITE SYMPHONIE

A traveling-wave tube of European origin for application in spacecraft power amplifiers is described. For the frequency range from 3. 7 to 4. 2 GHz, the tube delivers an optimum saturated output power of about 12-w at an overall efficiency of about 38%. Utilizing the special Alnice-alloy VS 55 developed by Krupp and special design techniques, a relative weight of less than 40 gm/w is obtained. It is shown that nonlinear distortions (am-pm- conversion and compression) are strongly dependent on such parameters as RF input (output) power and helix voltage. At an efficiency of 35% the am-pm- conversionis less than 4//0/db. Further, it is shown that optimum operation conditions exist for minimum intermodulation. The relevant parameters are different from those for optimum overall efficiency. Nickel A and 0. 1%-Zr nickel is used for cathode material. Results on life tests indicate that a life of more than 50,000 hr can be obtained.