High efficiency and wideband envelope tracking power amplifier with sweet spot tracking

This paper describes the implementation of a high efficiency and wideband envelope tracking power amplifier with sweet spot tracking. By modulating supply voltage of power amplifier (PA), efficiency can be increased significantly. And linearity is improved by envelope shaping and sweet spot tracking. The supply modulator has a combined structure of a switching amplifier and a linear amplifier to achieve high efficiency as well as wide bandwidth. The measurement results show efficiencies of 36.4/34.1% for 10/20 MHz long term evolution (LTE) signals with peak to average power ratio (PAPR) of 7.5/7.42 dB.