Multi-Line Based Efficient and Wideband Doherty Power Amplifier : Analytical Study

This article introduced a novel approach to enhance the bandwidth and efficiency of multi-line based Doherty Power Amplifiers (DPAs) by utilizing a impedance optimizing approach for impedance transformer networks (ITN). The ITN comprises multiple quarter wave transmission lines (QWTLs). A comprehensive analytical analysis is conducted, focusing on the impedance optimization of the QWTL lines. By carefully optimizing the impedance values of the QWTLs, a significant improvement in efficiency is achieved at 6-dB output power back-off (OPBO) level and peak power level across the frequency band. The proposed DPA demonstrates OPBO and peak power efficiency ranging from 65% to 80% across the 80% of fractional bandwidth in analytical simulations. Hence, an efficient and wideband DPA is attained in this work.