Integrated microfluidic cooling for GaN devices on multilayer organic LCP substrate

This paper presents, for the first time, an integrated microfluidic cooling scheme on multilayer organic liquid crystal polymer (LCP) substrate for high power X-band gallium nitride (GaN) devices and amplifiers. The channel is micromachined on LCP and a mixture of water and ethylene glycol is used as a coolant. A 3D electro-thermal model of the microfluidic channel has been created, which illustrates the advantage of having a micro-channel beneath LCP in the case of a static and moving fluid. Measurements were done at 10.5 GHz on a GaN power amplifier (P_DC = 1.68 W, PAE = 15 %) that was placed both on LCP and on a microfluidic channel with a static fluid.