Development of single-stage and Doherty GaN- based hybrid RF power amplifiers for quasi- constant envelope and high PAPR wireless standards

The paper describes the design, realization and characterization of a set of hybrid medium-power RF power amplifiers, based on a commercial packaged GaN HEMT and developed through a low-cost microstrip process. Two different design solutions suitable for wireless applications are presented: the first, intended for a constant-envelope modulation (with reference to the GSM standard), is a Class F amplifier exhibiting at 900 MHz an efficiency of 72 % with an output power of 37.5 dBm; the second, optimized for non-constant envelope signals with high dynamics (with reference to the UMTS WCDMA standard), is a Doherty amplifier showing, at 2.14 GHz, an efficiency higher than 40 % at 6 dB of output power back-off with a maximum output power of 40 dBm. GaN, power amplifier, microstrip, wireless communications, Doherty Corresponding author Roberto Quaglia Dep. of Electronics Politecnico di Torino C.so Duca degli Abruzzi 24 I-10129 Torino, Italy tel. +39-011-5644219 fax +39-011-5644149 email [email protected]