Title
Highly Efficient Wideband GaN MMIC Doherty Power Amplifier Considering the Output Capacitor Influence of the Peaking Transistor in Class-C Operation
Abstract
In this paper, a highly efficient gallium nitride (GaN) monolithic microwave integrated circuit (MMIC) Doherty power amplifier (DPA) from 4.6 to 5.5 GHz with the consideration of the influence of the peaking transistor’s output capacitor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(C_{\mathrm {out}}$ </tex-math></inline-formula> ) operated in Class-C state is presented. Based on the load-modulation behavior analysis, the effect of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {out}}$ </tex-math></inline-formula> of the peaking transistor on the performance of the wideband DPA has been theoretically analyzed for the first time by directly evaluating the value of the peaking transistor’s <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {out}}$ </tex-math></inline-formula> . A hybrid matching technique has been proposed to ensure that the DPA can realize a proper load-modulation with high back-off efficiency in a wide bandwidth. In this method, the peaking transistor is matched using a simple T-shape band-pass type network with the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {out}}$ </tex-math></inline-formula> of the peaking transistor in Class-C operation state compensated properly, while the carrier transistor is matched using a 2-point matching method. For verification, a wideband GaN MMIC DPA with the frequency range of 4.6 to 5.5 GHz was designed using a 0.25- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu {\mathrm{ m}}$ </tex-math></inline-formula> GaN on silicon-carbon high-electron-mobility transistor process. Experimental results show that the fabricated DPA can realize the output power of 41.1-41.6 dBm and the drain efficiency (DE) of 57.6%-63.3% at saturation in the whole frequency band. The measured DE at 6-dB power back-off is 51%-56.4%. Good linearity with high average efficiency performance was obtained when excited by a 160-MHz modulated signal after linearization.
Year
DOI
Venue
2022
10.1109/TCSI.2022.3149539
IEEE Transactions on Circuits and Systems I: Regular Papers
Keywords
DocType
Volume
Doherty power amplifier (DPA),gallium nitride (GaN),load-modulation,monolithic microwave integrated circuit (MMIC),output capacitor (Cout),wideband
Journal
69
Issue
ISSN
Citations 
5
1549-8328
0
PageRank 
References 
Authors
0.34
6
7
Name
Order
Citations
PageRank
Rui-Jia Liu100.34
Xiao-Wei Zhu202.37
Jing Xia300.68
Chen Peng41881121.56
Chao Yu512.06
Xiao-Liang Wu600.34
Chen Xiang73135.72