An Integrated Doherty Power Amplifier Module Based on an Advanced GaN-on-Si HEMT Technology and a Wideband Power Combiner

In this paper, a highly integrated and wideband Doherty power amplifier (PA) module for 5G mMIMO base station transceivers (BTS) is presented, leveraging the second generation of GaN-on-Si technology from Infineon. The advanced GaN-on-Si heterostructure field-effect transistor (HFET) delivers high power density and 75% drain efficiency at 3.6 GHz, while exhibiting very favorable output impedances for wideband matching. The module incorporates a simple and compact output combiner concept with effective 2nd harmonic termination, demonstrating very low dispersion over a wide RF bandwidth (600 MHz) at the output of 0.25 μm gate length GaN-on-Si transistors. The manufactured PA module achieves an efficiency of 51-53% and a gain of more than 15.8 dB across the 3.4-4.0 GHz band under a 100 MHz LTE signal with 8 W average output power. Linearized ACLR of -63.0 dBc and -42.0 dBc is achieved through digital predistortion for 20 MHz and 530 MHz LTE signals respectively.