High Power Density Structural Heat Spreader

ABSTRACT:The proposed research effort will develop passive Oscillating Heat Pipe (OHP) structural heat spreaders to attach to small, ultra-high heat flux devices (e.g., GaN power amplifiers) and dissipate their heat loads uniformly across the spreaders' relatively large heat sinking surfaces - and do so with minimal thermal resistance. The research team will design, model, fabricate, test, and analyze OHP-embedded heat spreaders made with innovative material stacks, variable internal surface structures, and three-dimensional channel patterns to meet the challenging thermal requirements of next-generation power amplifiers. Further, the unique material-fluid combinations will be utilized to allow for reliable operation during die attach, die removal, and thermal cycling. The small business will work with prime contractors and defense agencies to ensure the Phase I prototypes have a clear transition path for defense and commercial applications.BENEFIT:Status quo thermal management technologies are unable to transform the ultra-high heat fluxes of solid state power amplifiers to lower levels required by space-based thermal control systems. Power densities of GaN based power amplifiers are expected to exceed 1000 W/cm2 but spacecraft radiators and heat pipes have orders of magnitude to lower heat flux limits. New technologies are needed to bridge this gap. One promising technology is the Oscillating Heat Pipe or OHP. The OHP has proven ultra-high heat transport capacities and can be made from a wide variety of material-fluid combinations. This research effort will show how the OHP technology can be integrated into complex, thermally efficient material stacks for ultra-low resistance at the chip interface - and ultra high effective lateral thermal conductivity. Successful Phase I will create a new thermal solution to remove the constraints facing the advanced high channel density solid state power amplifiers.