Thermal Study on the Dependence of Contact Resistances on Helical SWS of TWTs

Broadband operation of traveling wave tubes (TWTs) demands the use of nonresonant helix structure as the slow-wave structure (SWS). But there are certain limitations to the power handling capabilities of helical SWS which require rigorous thermal investigations. Further, thermal contact resistances (TCRs) at the interfaces between various parts serve as a detrimental factor inhibiting the efficient thermal conduction in the SWS. Hence, authors have extensively studied the effect of TCRs at various interfaces on the thermal dissipation along with a developed analytical model. Moreover, the systematic thermal analysis of the SWS has been carried out for two different stuffing techniques-hot and cold stuffing, and the results have been compared with the perfect contact scenario. Different support rod materials have also been explored and their corresponding thermal and structural simulations are performed. Based on those results, hot-stuffed SWS performs thermally efficient resulting in 10% better thermal dissipation as compared to the cold-stuffed SWSs. Further recommendations on the support rod material to be used for efficient thermal dissipation are also provided.