Broadband Doherty power amplifiers: Advances and challenges

This paper expounds on the recent advancements in the area of broadband Doherty power amplifiers (DPA). It begins by outlining the major sources of performance limitations in DPAs when employed to efficiently amplify multi-band signals scattered over extended frequency bandwidth. It goes on to describe a number of novel techniques devised to broaden the bandwidth of classical two-way DPAs. Finally, a broadband three-way DPA is introduced as a potential solution to efficiently amplify signals with extended peak to average power ratios. Measurement results obtained using a number of broadband DPA demonstrators are reported.