A Bandwidth-Optimized Transformer-Based Doherty Power Amplifier for 5G Power Class 2 Handset operation at 2.2 GHz-2.7 GHz

This study presents a transformer-based Doherty combiner for a wideband Doherty amplifier suitable for use in a handset. The circuit topology configuration is based on closed-form equations. Circuit element values are optimized for wideband operation. An amplifier incorporating the combiner is fabricated with a laminated board and GaAs chip, and subsequently evaluated using 100 MHz bandwidth 5G signals. The amplifier operates in the range of 2.2-2.7 GHz with more than 35% efficiency and adequately low distortion when assisted by memory-less digital pre-distortion.