Driver Topologies for RF Doherty Power Amplifiers
In this letter, class-B, embedded class-B, and Doherty driver topologies are investigated for RF Doherty Power Amplifiers (PAs). The investigation is firstly conducted theoretically and by simulations and then verified by design and implementation of the different topologies at 2.1 GHz using GaN-HEMT transistors. The results show that the highest lineup efficiency can be achieved when using a Doherty driver. Modulated measurements using the same LTE signal and the same digital per-distorter (DPD), show about 2% and 4% higher average lineup efficiency when the Doherty driver is used compared to the class-B and embedded class-B drivers, respectively.