3D Printed Thermal Management System for the Next Generation of Gallium Nitride-based Solid State Power Amplifiers
Current Gallium Nitride (GaN)-based solid state power amplifiers (SSPAs) are limited in their operational capabilities due to the limitations of the overall thermal management system in dissipating the high heat fluxes. However, GaN based SSPAs are desirable for satellite communication due to their superior linearity, built-in redundancy, reliability, power density and energy efficiency as compared to current technologies such as traveling wave tube amplifiers (TWTAs). In order to enable higher power GaN amplifiers and next generation phased arrays, it is critical to reduce the heat flux on the thermal management system by spreading the heat efficiently across a larger area. Aluminum/ammonia constant conductance heat pipes have been a proven technology for spacecraft thermal control for more than 40 years with both high heat transport capability (76 to 254 Watt-m) and reasonably low mass. Unfortunately, ammonia only works up to about 80°C, while the use of high- temperature electronics such as GaN power amplifiers, allows operation up to 150 °C. This further allows significant reduction in radiator size and mass. Advanced Cooling Technologies, Inc. (ACT) is devloping a novel, low-cost and low-mass thermal management system (TMS) which is capable of handling power densities and temperatures of next generation GaN power amplifiers and phased arrays. The design is based on integration of 3D printed vapor chamber and freeze/thaw tolerant titanium-water heat pipes with several novel features designed to ensure cooling of GaN devices during start-up or operation in space (vacuum and zero gravity) as well as earth environments.