Back-Off Range Extension of Doherty Power Amplifier Using Parasitic Capacitance Compensation

Fu Cheng Yuan; Bai Hua Zeng; Shao Yong Zheng

doi:10.1109/LMWT.2025.3557507

Back-Off Range Extension of Doherty Power Amplifier Using Parasitic Capacitance Compensation

Fu Cheng Yuan, Bai Hua Zeng, Shao Yong Zheng^*

^*Corresponding author for this work

Department of Electrical Engineering

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

Abstract

Efficiencies of a Doherty power amplifier (DPA) at output back-off (OBO) levels are limited by the parasitic parameters of transistors. To deal with this issue, an effective approach is proposed in this letter to enhance efficiency and the OBO range of a DPA. An equivalent negative capacitance network (ENCN) is utilized to compensate for reactive impedances of the carrier amplifier, which can significantly boost efficiency at the deep back-off. For validation, an asymmetric DPA utilizing the out-phased current combining method is designed to achieve an extended OBO range. When the operating frequency is 2.55 GHz in continuous-wave measurement, the implemented DPA can obtain drain efficiencies of 54.8% at 11.6-dB OBO level and 74.4% at saturation (43.1 dBm), respectively.

© 2025 IEEE. All rights reserved, including rights for text and data mining, and training of artificial intelligence and
similar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission.

Original language	English
Journal	IEEE Microwave and Wireless Technology Letters
Online published	28 Apr 2025
DOIs	https://doi.org/10.1109/LMWT.2025.3557507
Publication status	Online published - 28 Apr 2025

Funding

This work was supported in part by the National Natural Science Foundation of China under Grant 62471507 and in part by the Research Grants Council (RGC) Hong Kong under Grant AoE/E-101/23-N.

Research Keywords

Asymmetric
Doherty power amplifier (DPA)
extended back-off range
high efficiency
negative capacitance

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title = "Back-Off Range Extension of Doherty Power Amplifier Using Parasitic Capacitance Compensation",

abstract = "Efficiencies of a Doherty power amplifier (DPA) at output back-off (OBO) levels are limited by the parasitic parameters of transistors. To deal with this issue, an effective approach is proposed in this letter to enhance efficiency and the OBO range of a DPA. An equivalent negative capacitance network (ENCN) is utilized to compensate for reactive impedances of the carrier amplifier, which can significantly boost efficiency at the deep back-off. For validation, an asymmetric DPA utilizing the out-phased current combining method is designed to achieve an extended OBO range. When the operating frequency is 2.55 GHz in continuous-wave measurement, the implemented DPA can obtain drain efficiencies of 54.8% at 11.6-dB OBO level and 74.4% at saturation (43.1 dBm), respectively. {\textcopyright} 2025 IEEE. All rights reserved, including rights for text and data mining, and training of artificial intelligence andsimilar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission.",

keywords = "Asymmetric, Doherty power amplifier (DPA), extended back-off range, high efficiency, negative capacitance",

author = "Yuan, {Fu Cheng} and Zeng, {Bai Hua} and Zheng, {Shao Yong}",

year = "2025",

month = apr,

day = "28",

doi = "10.1109/LMWT.2025.3557507",

language = "English",

journal = "IEEE Microwave and Wireless Technology Letters",

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TY - JOUR

T1 - Back-Off Range Extension of Doherty Power Amplifier Using Parasitic Capacitance Compensation

AU - Yuan, Fu Cheng

AU - Zeng, Bai Hua

AU - Zheng, Shao Yong

PY - 2025/4/28

Y1 - 2025/4/28

N2 - Efficiencies of a Doherty power amplifier (DPA) at output back-off (OBO) levels are limited by the parasitic parameters of transistors. To deal with this issue, an effective approach is proposed in this letter to enhance efficiency and the OBO range of a DPA. An equivalent negative capacitance network (ENCN) is utilized to compensate for reactive impedances of the carrier amplifier, which can significantly boost efficiency at the deep back-off. For validation, an asymmetric DPA utilizing the out-phased current combining method is designed to achieve an extended OBO range. When the operating frequency is 2.55 GHz in continuous-wave measurement, the implemented DPA can obtain drain efficiencies of 54.8% at 11.6-dB OBO level and 74.4% at saturation (43.1 dBm), respectively. © 2025 IEEE. All rights reserved, including rights for text and data mining, and training of artificial intelligence andsimilar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission.

AB - Efficiencies of a Doherty power amplifier (DPA) at output back-off (OBO) levels are limited by the parasitic parameters of transistors. To deal with this issue, an effective approach is proposed in this letter to enhance efficiency and the OBO range of a DPA. An equivalent negative capacitance network (ENCN) is utilized to compensate for reactive impedances of the carrier amplifier, which can significantly boost efficiency at the deep back-off. For validation, an asymmetric DPA utilizing the out-phased current combining method is designed to achieve an extended OBO range. When the operating frequency is 2.55 GHz in continuous-wave measurement, the implemented DPA can obtain drain efficiencies of 54.8% at 11.6-dB OBO level and 74.4% at saturation (43.1 dBm), respectively. © 2025 IEEE. All rights reserved, including rights for text and data mining, and training of artificial intelligence andsimilar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission.

KW - Asymmetric

KW - Doherty power amplifier (DPA)

KW - extended back-off range

KW - high efficiency

KW - negative capacitance

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UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-105004066060&origin=recordpage

U2 - 10.1109/LMWT.2025.3557507

DO - 10.1109/LMWT.2025.3557507

M3 - RGC 21 - Publication in refereed journal

SN - 2771-957X

JO - IEEE Microwave and Wireless Technology Letters

JF - IEEE Microwave and Wireless Technology Letters

ER -

Back-Off Range Extension of Doherty Power Amplifier Using Parasitic Capacitance Compensation

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Back-Off Range Extension of Doherty Power Amplifier Using Parasitic Capacitance Compensation

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