A review of Doherty power amplifier and load modulated balanced amplifier for 5G technology

In this paper, functionality of the Doherty power amplifiers (DPAs) along with their design constraints such as DPA combining techniques are reviewed. This is because power amplifier (PA) is a key building block in the design of fifth generation (5G) communication systems. A significant trend is the DPA bandwidth enhancement technique, which is the subject of numerous papers in the literature. So, we will review some papers with different solutions to address DPA's bandwidth limitations. There are also different works in the literature that have focused on high-efficiency PA structure designs, which are also discussed in this paper. An excellent option for effective power combining in broadband designs is using balanced amplifiers. We have discussed load modulated balanced amplifiers (LMBA) in this paper because designing an effective PA with a wide bandwidth is crucial. We also covered some papers that have proposed techniques based on the linearization method to bring the efficiency and linearity of DPAs to a fair level.