Direct Die Attached CTE Matched Ultra High Thermal Conductivity Graphite/Aluminum Heat Sinks for High RF Power Density Phased Array Radar Systems

A new metal matrix composite material consisting of natural graphite particulates processed into a designed reinforcement architecture that, after pressure infiltration casting with molten Al alloy, results in materials with thermal conductivity (TC) controllable over a range of 600 to 750 W/mK and thermal expansion controllable over the range of 7 to 3 ppm/K. This material, with strategically located high TC “z” inserts is proposed as base plate heat sinks for advanced GaN based phased array radar systems. The material system will be fully characterized. FEA thermal models will be developed for a 4 by 4 channel prototype array which will be manufactured for attachment to T/R module emulators and evaluated by a prime contractor partner for thermal performance. The goal is to enable a two- to three-fold increase in power density in wide bandgap semiconductors and to manufacture radar arrays with greater than 100 channels within essentially a page sized format. The constituent materials are inexpensive. Hence, the proposed technology, at the proper manufacturing scale will provide materials with a cost per unit volume less than copper at 1.5 to 2 times the thermal performance and CTE matching to the T/R module.