A 3.7GHz GaN HEMT Doherty power amplifier using digital predistortion linearization

Author

Jeong, Jonghyuk ; Van, Juho ; Cho, Jaeyong ; Kim, Min-su ; Cho, Hanjin ; Lim, Kyunghoon ; Kwon, Sung-wook ; Choi, Kyonggon ; Kim, Hyung-chul ; Yoo, Sungcheol ; Yang, Youngoo

Author_Institution

Sch. of Inf. & Commun. Eng., Sungkyunkwan Univ., Suwon

fYear

2008

fDate

16-20 Dec. 2008

Firstpage

1

Lastpage

4

Abstract

In this study, we implemented a 3.7 GHz band Doherty amplifier based on GaN HEMTs which was linearized using a digital predistortion method. The forward and reverse models of the predistortion consist of simple polynomials whose coefficients are extracted using a conventional LMSE algorithm. Using two carrier signals based on IEEE 802.16e, whose PAR is 9.44 dB, an ACLR improvement of 10.74 dB was 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 to that of a balanced class-AB power amplifier at an average power of 36 dBm.

Keywords

gallium compounds; high electron mobility transistors; least mean squares methods; microwave amplifiers; microwave transistors; power amplifiers; GaN; HEMT Doherty power amplifier; IEEE 802.16e; digital predistortion linearization; efficiency 13.74 percent; efficiency 2.44 percent; frequency 3.7 GHz; frequency 4.79 MHz; least mean square method; Gallium nitride; HEMTs; High power amplifiers; Linearity; Operational amplifiers; Polynomials; Power amplifiers; Power generation; Predistortion; Radiofrequency amplifiers;

fLanguage

English

Publisher

ieee

Conference_Titel

Microwave Conference, 2008. APMC 2008. Asia-Pacific

Conference_Location

Macau

Print_ISBN

978-1-4244-2641-6

Electronic_ISBN

978-1-4244-2642-3

Type

conf

DOI

10.1109/APMC.2008.4958375

Filename

4958375