Multistage Depressed Collector With Improved Thermal Management for High Efficiency Travelling Wave Tubes

Multistage depressed collectors (MDCs) are used to enhance the overall efficiency of travelling-wave tubes (TWTs). Thermal management is one of the critical concerns when such TWTs are used for space application. In this paper, authors have presented an innovative technological concept to develop a typical four stage MDC in a single ceramic for better thermal management. Here, multiple brazing joints have been reduced, which, in turn, reduces thermal contact resistances (TCRs) and thereby improves the thermal management better than its conventional counterpart, where brazing joints are more. A 1-D analytical model has been developed for better understanding of the effect of TCRs at various braze joints on heat dissipation from the MDC. Results obtained from this analytical model have been compared with 3-D simulations and validated experimentally.