Thermal Pyrolytic Graphite (TPG) Embedded Copper Graphite Composite Heat Sink for High Power or Small Form Factor (SFF) Tactical Radios

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 the power amplifier heat sink so that heat can be conducted from its edge into the radio chassis. The enhancement of thermal performance by TPG insertion allows applications where advanced wide band gap semiconductors, such as GaN and SiC, are mixing with other low temperature components. At an average heat flux of 100 W/cm2, which is assumed at the die level for SiC 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 total thermal management of SiC devices whose junction temperature can be as high as 300 °C.