A Fully Integrated High-Efficiency Three-stage Doherty Power Amplifier for Small-cell application

In this paper, a high-performance three-stage Doherty power amplifier was designed for 5G small-cell base station (SBSs) applications and fully fabricated in GaAs HBT technology with a dimension of 2.2 × 3mm². An asymmetric configuration and even power splitting was utilized to get deeply back-off region and good performance. An optimal output match network is applied to overcome the problem from high output power. Test results show that the average power-add efficiency (PAE) above 30% and power gain of 34dB were attained for a 20MHz long-term evolution signal with an 8-dB peak-to-average power ratio. The adjacent channel leakage ratio was -30.2 dBc without any linearization, and it was improved to -50.3 dBc with a digital pre-distortion linearization.