Novel Design Space of Broadband High-Efficiency Parallel-Circuit Class-EF Power Amplifiers

• Published in: IEEE transactions on circuits and systems. I, Regular papers Vol. 69; no. 9; pp. 3465 - 3475
• Main Authors: Liu, Chang, Zhang, Hao, Chen, Wenhua, Ghannouchi, Fadhel M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Broadband; Broadband communication; Chebyshev approximation; Circuit design; class-EF; design space; high-efficiency; Impedance; Inductance; Mathematical models; parallel-circuit; Power amplifiers; Power gain; Switches; Transistors; Voltage
• ISSN: 1549-8328; 1558-0806
• DOI: 10.1109/TCSI.2022.3177283

This article proposes a broadband high-efficiency parallel-circuit (PC) class-EF power amplifier (PA) along with a quarter-wavelength stub for the first time. By adding a reactive element <inline-formula> <tex-math notation="LaTeX">{X} </tex-math></inline-formula>, the design space is expanded so that the impedance terminations of the fundamental and harmonics are no longer fixed points. Based on the broadband capability of the proposed structure, using a GaN HEMT transistor, a proof-of-concept circuit implemented with the Chebyshev impedance transformation network is designed and fabricated. Experimental results demonstrate a high-efficiency broadband PA operating from 2.6-3.9 GHz, with the average efficiency of 71.5%, the measured output power (<inline-formula> <tex-math notation="LaTeX">{P}_{\textit {out}} </tex-math></inline-formula>) of 38.8-40.9 dBm and the power gain of 8.5-10.6 dB.