A Highly Efficient Feed-Forward Doherty Amplifier with Improved Group-delay performance

Author

Qing, Zheng ; Bo, Yan

Author_Institution

Univ. of Electron. Sci. & Technol. of China, Chengdu

fYear

2008

fDate

10-12 Sept. 2008

Firstpage

544

Lastpage

546

Abstract

In this paper, a RF high power Doherty feed-forward amplifier using equal group-delay canceller is proposed which provide high efficiency and high linearity also with improved group-delay performance. The Doherty amplifier takes Freescale mrf21125S N-channel Enhancement-Mode Lateral MOSFETs as the main amplifier of a feed-forward amplifier. By carefully adjust the gate bias and the phase offset line as well as through a 3 dB hybrid group-delay canceller, at the output of 25 W the amplifier performs with 44 dB better adjacent channel leakage power ratio (ACLR), 3.9% higher power added efficiency (PAE) than conventional Class-AB feed-forward amplifier.

Keywords

MOSFET circuits; feedforward amplifiers; leakage currents; power amplifiers; radiofrequency amplifiers; ACLR; RF high power Doherty feed-forward amplifier; adjacent channel leakage power ratio; conventional class-AB feed-forward amplifier comparison; freescale mrf21125S N-channel enhancement-mode lateral MOSFET; gate bias adjustment; hybrid group-delay canceller performance; phase offset line; power 25 W; power added efficiency; Bandwidth; Broadband amplifiers; Circuits; Feedforward systems; High power amplifiers; Impedance; Linearity; Multiaccess communication; Radio frequency; Radiofrequency amplifiers; ACLR; Doherty amplifier; Feed-forward; Group-delay canceller; PAE;

fLanguage

English

Publisher

ieee

Conference_Titel

Microwave Conference, 2008 China-Japan Joint

Conference_Location

Shanghai

Print_ISBN

978-1-4244-3821-1

Type

conf

DOI

10.1109/CJMW.2008.4772490

Filename

4772490