A 3.5GHz High Power GaN Hybrid Doherty Power Amplifier with Dynamic Input Power Splitting for Enhanced Power Added Efficiency at Backoff

Abstract

In this paper, a hybrid Doherty power amplifier (DPA) using dynamic input power splitting for 3.5 GHz is presented and compared to another Doherty with a conventional Wilkinson input divider sharing the same output structure. The amplifier is designed in a novel hybrid configuration, where a MMIC consisting of two parallel GaN transistors with input prematching are fully integrated on chip and used as the main and peak amplifiers. The remaining passive structures are implemented at PCB level on a RO4350B. The results at 3.5 GHz under continuous wave operation show 45 dBm of maximum output power with over 41% of PAE and Drain efficiency over 47% in a 6dB output power backoff (OBO) and 7 dB of gain for maximum output power.