High-Efficiency Doherty Power Amplifier Based on an Asymmetric Structure

This study presents a Doherty power amplifier (DPA) based on an asymmetric structure using an uneven power divider and different power amplifier(PA) transistors between main and auxiliary PAs, which not only expands the power back-off level but also achieves a high efficiency. After providing an analysis of the fundamental theory, a design guide for the proposed DPA is presented. For verification, the conventional and proposed DPAs are designed and compared. Using test instruments from Agilent, the proposed DPA exhibits comparably better performances than the conventional DPA, such as a high power-added efficiency of 44%, a power back-off level as high as 7dB, and a power gain of 13dB at the output power of 42dBm