Integrated Microfluidic Cooling for S-Band 10-Watt CW Power Amplifiers on Hybrid PCBs

This paper presents an integrated microfluidic channel on a Rogers and FR4 hybrid printed circuit board (PCB) to cool an S-band 10 W CW (continuous-wave) power amplifier in a plastic surface mount package. A four-layer hybrid PCB has been designed and fabricated, whose fabrication process is completely based on the standard multilayer PCB technology. The thermal and RF experimental results show that the integrated microfluidic cooling scheme on the multilayer hybrid PCB is effective. The case temperature of the power amplifier is decreased to 44 °C at the water flow rate of 325 mL/min, while the power-added efficiency (PAE) of 42.6% and the CW output power of 41.2 dBm are obtained at 2.1 GHz. In a comparative experiment, the power amplifier outputting the same CW power on the PCB failed within tens of seconds using conventional cooling methods.