A high efficiency, 10 kW TWT employing an electron beam velocity resynchronization technique

Summary form only given, as follows. This report will detail the design and describe the performance characteristics of a 10 kllf coupled-cavity traveling wave tube (TWT) with a total system efficiency greater than 50% (including focusing and cooling power requirements) over the 4.4 to 5.0 GHz military troposcatter frequency band. The TWT utilizes an integral "wrapped on" solenoid for superior beam control and a closed-cycle, gravity-fed vapor phase nucleate boiling cooling system for heat transfer and high cooling efficiency. High interaction efficiency is obtained from the tube by use of a "voltage jump" electron beam velocity resynchronization technique in conjunction with two-stage collector depression. The voltage jump principle is a technique whereby the electron beam is reaccelerated (by application of a positive voltage to a section of the TWT slow wave circuit) back into synchronism with the phase velocity of the RF wave, thereby prolor~ing the distance over which favorable large signal interaction can occur. The results presented demonstrate that the voltage jump technique can generate interaction efficiencies greater than 70%, an accomplishment never before even closely approached by o-type traveling wave tubes, with the concommitant result that total system efficiencies greater than 50% across the entire 13% troposcatter fractional bandwidth can be realized.