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).

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Abstract:

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.