A 53% PAE envelope tracking GaN power amplifier for 20MHz bandwidth LTE signals at 880MHz

Abstract

This paper presents a high efficiency envelope tracking (ET) GaN power amplifier (PA) operated at 880MHz, for wide bandwidth signals. Using a 16-QAM 20MHz bandwidth LTE signal with 6.6dB PAPR, a 54.4% drain efficiency and 52.8% power added efficiency (PAE), including both the envelope amplifier (EA) and the RF-PA, were measured, along with a 15.3dB gain and 7.4-W output power. The corresponding EVM and E-UTRA ACPR1 were 1.88% and -48.5dBc, meeting the linearity specifications. The linearity was achieved using a novel digital predistortion (DPD) technique. To the best of the authors' knowledge, the PAE sets a new record for high power ET PAs with 20MHz bandwidth high PAPR signals. It also demonstrates the best comprehensive performances of the ET PA, in terms of efficiency, gain, bandwidth and linearity.