Further Efficiency Improvement of Power Amplifiers Using Thermal Energy Harvesting

This letter proposes a method to further improve the efficiency of power amplifiers (PAs). A thermoelectric generator is used to harvest the thermal energy produced by the PA and transform it into electric energy. Then, the efficiency of the PA can be improved by feeding the obtained electric energy to the drain power supply via a dc-dc converter. For verification, a 10-W 3.2-3.8-GHz class-F PA for base station applications is built; the generated temperature distribution and the process of energy conversion are evaluated. Cost-effective commercial chips are applied to harvest, transform, convert, and feedback the energies to the drain supply. The measurement results demonstrate an improvement of 1.1% drain efficiency at the peak output.