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Linearization of a 3.7 GHz multi‐carrier GaN HEMT Doherty power amplifier using digital predistortion method
Author(s) -
Jeong Jonghyuk,
Van Juho,
Cho Jaeyong,
Kim MinSu,
Cho Hanjin,
Lim KyungHoon,
Kwon SungWook,
Choi Kyonggon,
Kim HyungChul,
Yoo Sungcheol,
Park CheonSeok,
Yang Youngoo
Publication year - 2010
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.24984
Subject(s) - predistortion , amplifier , doherty amplifier , dbc , electronic engineering , linearization , microwave , electrical engineering , linear amplifier , high electron mobility transistor , engineering , adjacent channel , linearity , adjacent channel power ratio , power (physics) , rf power amplifier , telecommunications , cmos , physics , transistor , nonlinear system , voltage , quantum mechanics
In this article, a 3.7 GHz band Doherty amplifier based on GaN HEMTs, which is linearized using a digital predistortion method, is implemented for 4th generation wireless communication systems. The forward and reverse models of the Doherty amplifier for the predistortion consist of simple polynomials whose coefficients are extracted using a conventional least mean square error algorithm. Using a two carrier signal based on IEEE802.16e, whose PAR is 9.44 dB, an ACLR improvement of 10.74 dB is achieved to give an ACLR level of 41.74 dBc at an offset of 4.79 MHz. The overall efficiency of the Doherty power amplifier is 13.74%, which represents a 2.44% improvement compared with that of a balanced class‐AB power amplifier at an average output power of 36 dBm. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 634–638, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24984