Investigation of High-Efficiency Parallel-Circuit Class-EF Power Amplifiers With Arbitrary Duty Cycles

• Published in: IEEE transactions on industrial electronics (1982) 2021-06, Vol.68 (6), p.5000-5012
• Main Authors: Liu, Chang, Li, Xiang, Zhao, Yulong, Qi, Tian, Du, Xuekun, Chen, Wenhua, Ghannouchi, Fadhel M.
• Format: Article
• Language: English
• Subjects: 5G mobile communication; Capacitance; Circuit design; Class-EF; Design optimization; Design parameters; duty cycles; high-efficiency; Inductance; parallel circuit; Power amplifiers; quarter-wave transmission line; Switches; Transistors; Transmission lines
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2020.2991924

In this article, a parallel-circuit class-EF power amplifier with a shunt quarter-wave transmission-line for driving signals with arbitrary duty cycles is proposed and investigated. At the particular condition of duty cycle = 1/3, the values of the elements in the output network, as well as, some critical design parameters are analyzed and optimized. This leads to a series of significant improvements in the peak drain voltage ( V max ), the maximum operating frequency ( f max ), and the power output capability ( c p ). Furthermore, in order to verify the advantage of the proposed new amplifier and its feasibility in realistic situations, a proof-of-concept circuit is designed and fabricated. Finally, at the operating frequency of 3.59 GHz, excellent performance has been achieved with the power-added efficiency of 79.9% and output power of 40.7 dBm.