Thermal Pyrolytic Graphite (TPG) Embedded Copper Graphite Composite Heat Sinking Slat for Phase Array Radar Antenna

A manufacturing technique is developed to strategically embed thermal pyrolytic graphite (TPG) insert into copper graphite composite. TPG will then be located in the critical thermal path of phase array radar antenna slat so that the slat is allowed to be cooled from its edge. The enhancement of thermal performance by TPG insertion allows the antenna slat to be cooled at its edge while the advanced wide band gap semiconductors, such as GaN and SiC, are used in the microwave modules. At an average heat flux of 100 W/cm2, which is assumed at the module level for GaN devices, the temperature difference along the thermal path of 1.5" long, in the case of copper graphite composite, from module mounting surface to cooling fins was estimated as only 8 °C, using a simplified one-dimensional heat transfer method. This temperature drop is adequate for the total thermal management of GaN devices whose junction temperature can be as high as 250 °C.