Doherty Power Amplifier with Compact Load Modulation Network for 5G Applications

This paper presents a Doherty power amplifier (DPA) with a compact load modulation network designed in 65nm bulk-CMOS process. The output network comprises a parallel-tuned transformer and a lumped equivalent quarter-wave transformer. The intrinsic drain capacitance of the power amplifier cells and inductances of the lumped L-C-L impedance inverter are absorbed in the load modulation network, thus making it very compact and efficient. The simulated results of the proposed DPA have a saturated output power of 20.4 dBm with a peak PAE of 28.5% at 28 GHz. It also shows PAE of 16.7% at 6dB power back-off and 21% at P
1dB
. The peak PAE is more than 20%, and the PAE at 6 dB back-off is more than 10% for the band of 27 GHz to 29 GHz. The load modulation network has an insertion loss of only 1.25 dB and an area of 0.056 mm
²
.