Packaging and Thermal Management for kW/cm2 Microwave Amplifiers

The overall goal of this project is to develop a heat removal technology to handle heat flux densities as high as 1 kW/cm2 for wide band gap SiC/GaN microwave power amplifers, which will be utilized in X- band phased array radar antennas. The technologydeveloped in Phase I is based on a large array of micro-scale impinging jets, each of which produces a very high rate of heat transfer over a localized area. This heat removal system is extremely compact and compatible with existing thermal managementcooling loops in navy radar systems. The micro-jet cooling arrays (MJCA) principle of operation combines the well-known benefits of impinging jets (impingement cooling) with a unique ducting system that locally removes the impinging fluid of each jet,eliminates cross-flow, and prevents the flow fields of neighboring jets from interfering with each other. The local removal of fluid makes it possible to use large arrays (i. e. 100s x 100s) of isolated micro jets to achieve extremely high average heattransfer coefficients over relatively large areas (square inches). Therefore, the system can easily cool areas as large as the 1.5 cm x 1.5 cm footprint of X band modules. The end product is a compact, efficient, heat-removal device that can be retrofitedinto many existing applications. Commercial applications would include military applications and ground based radar for commercial airports and weather radar.