Abstract This article 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 nonconstant 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. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:206–210, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26459