Title :
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
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;
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
DOI :
10.1109/APMC.2008.4958375
