Broadband Class-J GaN Doherty Power Amplifier

Abstract

This paper presents a broadband 3 GHz–3.7 GHz class-J Doherty power amplifier exploiting second harmonic tuning in the output network. Furthermore, the output impedance inverter is eliminated and its effect is embedded in the main device’s output matching network, thus trading off among bandwidth, efficiency, and gain. The proposed amplifier adopts two 10 W packaged GaN transistors, and it achieves in measurement 60–74%, and 46–50% drain efficiency at saturation and 6 dB output back-off, respectively, with a saturated output power of 43 dBm–44.2 dBm and a small-signal gain of 10 dB–13 dB. The proposed DPA exhibits a simulated adjacent channel power ratio less than −30 dBc at 36 dBm average output power, when a 16-QAM modulation with 5 MHz bandwidth is applied to the 3.5 GHz carrier.