A highly integrated multiband LTE SiGe power amplifier for envelope tracking

This paper presents a highly integrated SiGe power amplifier (PA) for multiband long-term evolution (LTE). Two different harmonic loadings are investigated for the PA to achieve the optimized efficiencies for the envelope tracking (ET) and average power tracking (APT), respectively. By adopting the proper PA structure, our ET PA delivers >39% overall power-added efficiency (PAE) at the maximum output power (Pout) of 26.5 dBm with ACLREUTRA below −42 dB and EVM below 1% for the LTE QPSK 10 MHz at 699–716 MHz, 824–915 MHz and 1710–1980 MHz. At the back-off more than 5 dB below the maximum Pout, the ET PA is reconfigured to APT for remaining high overall PAE and linearity across a broad Pout range.