A Three-Level Class-G Modulated 1.85 GHz RF Power Amplifier for LTE Applications with over 50% PAE

N. Wolff1, W. Heinrich1, M. Berroth2 and O. Bengtsson1

Published in:

IEEE MTT-S Int. Microw. Symp. Dig., San Francisco, USA, May 22-27, Tu4B-4 (2016).

Copyright © 2016 IEEE - All Rights Reserved. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.


A highly efficient three-level class-G modulated RF power amplifier (PA) is presented. The PA is designed to operate as downlink amplifier in the 1800-1900 MHz LTE-band. At 1.85 GHz the maximum output power under continuous wave excitation is 48.2 dBm (66 W). The system achieves an overall efficiency of more than 50% when amplifying a 20 MHz OFDM signal with 9 dB peak-to-average power ratio at 40 dBm (10 W) average output power and over 15 dB gain. In combination with digital predistortion the class-G modulated PA can achieve an ACLR of -36.2 dB and an EVM of 2.1%. The class-G modulation enables excellent efficiency due to absence of a linear amplifier in the modulator stage. The efficiency improvement due to the three-level class-G modulation reaches 18.7 percentage points.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
2 Universität Stuttgart, Institute of Electrical and Optical Communications Engineering (INT), 70569 Stuttgart, Germany

Index Terms:

Class-G supply modulation, envelope tracking, RF power amplifiers, digital predistortion, linearization.