volume | PIER Journals

Abstract

A highly efficient asymmetrical GaN Doherty power amplifier using traditionalλ/4 transmission line and an asymmetrical GaN Doherty power amplifier(DPA) using composite right/left-handed transmission lines(CRLH-TL) for linearity improvement are presented in this paper.The CRLH-TL is designed to suppress the second harmonic of the output of the carrier amplifier. This DPA using CRLH-TL is designed for 3.5 GHz LTE-Advanced Application with 100 MHz bandwidth and 37 dBm average output power, the carrier and peaking amplifiers are fabricated with the same 30 W GaN HEMT and unevenly driven in purpose of maintaining high efficiency at back-off power (BOP) region. At 9-dB and 6-dB BOP, the DE achieves 30% and 40.1%, respectively, and the adjacent channel power ratio(ACPR) are less than-37.1 dBc for 40 MHz 16 QAM signal at 37 dBm. In addition, the further linearization of the DPA is realized by using digital pre-distortion(DPD), the ACPRs are improved to-49.6 dBc for 40 MHz 16 QAM signal.The measured results show linearity improvement compared with the traditional DPA.

1. Steer, M., Beyond 3G, Vol. 8, No. 1, 76-82 IEEE Microwave Magazine, 2007.

2. Ratasuk, R., B. Mondal, N. Mangalvedhe, and T. Thomas, "LTE-Advanced: Next-generation wireless broadband technology," IEEE Wireless Communications, Vol. 17, No. 3, 10-22, 2010.
doi:10.1109/MWC.2010.5490974

3. Baker, M., "From LTE-advanced to the future," IEEE Communications Magazine, Vol. 50, No. 2, 116-120, 2012.
doi:10.1109/MCOM.2012.6146490

4. Akimoto, Y., Y. Kim, M.-I. Lee, K. Bhattad, and A. Ekpenyong, "Evolution of reference signals for LTE-Advanced systems," IEEE Communications Magazine, Vol. 50, No. 2, 132-138, 2012.
doi:10.1109/MCOM.2012.6146492

5. Karkhaneh, H., A. Ghorbani, and H. Amindavar, "Modeling and compensating memory effect in high power amplifier for OFDM systems," Progress In Electromagnetics Research C, Vol. 3, 183-194, 2008.
doi:10.2528/PIERC08041201

6. Du, T., C. Yu, Y. Liu, J. Gao, S. Li, and Y. Wu, "A new accurate Volterra-based model for behavioral modeling and digital predistortion of RF power amplifiers," Progress In Electromagnetics Research C, Vol. 29, 205-218, 2012.

7. Dhar, J. and R. K. Arora, "Enclosure effect on microwave power amplifier," Progress In Electromagnetics Research C, Vol. 19, 163-177, 2011.

8. Yang, J.-R., H.-C. Son, and Y.-J. Park, "A class E power amplifier with coupling coils for a wireless power transfer system," Progress In Electromagnetics Research C, Vol. 35, 13-22, 2013.

9. Zhou, H.-J. and H. F. Wu, "Design of an S-band two-way inverted asymmetrical Doherty power amplifier for long term evolution applications ," Progress In Electromagnetics Research Letters, Vol. 39, 73-80, 2013.

10. Pelk, M. J. and W. C. Edmund Neo, "A high-efficiency 100-W GaN three-way Doherty amplifier for base-station applications," IEEE Trans. Microw. Theory Tech., Vol. 56, No. 7, 1582-1591, 2008.
doi:10.1109/TMTT.2008.924364

11. Chen, W., S. A. Bassam, X. Li, and Y. Liu, "Design and linearization of concurrent dual-band Doherty power amplifier with frequency-dependent power ranges," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 10, 2537-2546, 2011.
doi:10.1109/TMTT.2011.2164089

12. Kim, J., J. Moon, Y. Y. Woo, S. Hong, I. Kim, J. Kim, and B. Kim, "Analysis of a fully matched saturated Doherty amplifier with excellent efficiency," IEEE Trans. Microw. Theory Tech., Vol. 56, No. 2, 328-338, 2008.
doi:10.1109/TMTT.2007.914361

13. Ma, R., Z. Wang, X. Yang, and S. Lanfranco, "Implementation of a current-mode class-S RF power amplifier with GaN HEMTs for LTE-Advanced," Wireless and Microwave Technology Conference, 1-6, 2012.

14. Tanany, A., A. Sayed, and G. Boeck, "Analysis of broadband GaN switch mode class-E power amplifier," Progress In Electromagnetics Research Letters, Vol. 38, 151-160, 2013.

15. Lin, S. and A. E. Fathy, "Development of a wideband highly e±cient GaN VMCD VHF/UHF power amplifier," Progress In Electromagnetics Research C, Vol. 19, 135-147, 2011.

16. Ji, S. H., S. K. Eun, and C. S. Cho, "Linearity improved Doherty power amplifier using composite right/left-handed transmission lines," IEEE Microwave and Wireless Components Letters, Vol. 18, No. 8, 533-535, 2008.
doi:10.1109/LMWC.2008.2001014

17. Lin, I-H., M. DeVincentis, and C. Caloz, "Arbitrary dual-band components using composite right/left-handed transmission lines," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 4, 1142-1149, 2004.
doi:10.1109/TMTT.2004.825747

18. Cripps, S. C., RF Power Amplifiers for Wireless Communications, Artech House, Norwood, MA, 2006.

19. Kim, J., J. Cha, I. Kim, and B. Kim, "Optimum operation of asymmetrical-cells-based linear Doherty power amplifiers --- Uneven power drive and power matching ," IEEE Trans. Microw. Theory Tech., Vol. 53, No. 5, 1802-1809, 2005.
doi:10.1109/TMTT.2005.847073

20. Kim, J., B. Fehri, S. Boumaiza, and J. Wood, "Power efficiency and linearity enhancement using optimized asymmetrical Doherty power amplifiers," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 2, 425-434, 2011.
doi:10.1109/TMTT.2010.2086466

21. Darraji, R., F. M. Ghannouchi, and O. Hammi, "Generic load-pull-based design methodology for performance optimisation of Doherty amplifiers," IET Science, Measurement and Technology, Vol. 6, No. 3, 132-138, 2012.
doi:10.1049/iet-smt.2011.0023

22. Hammi, O., S.-C. Jung, and F. M. Ghannouchi, "Design for linearizability of GaN based multi-carrier Doherty power amplifier through bias optimization ," Electronics, Circuits and Systems (ICECS), 492-495, 2012.

23. Seung, S., H. Ji, and C. S. Cho, "Concurrent dual-band class-E power ampli¯er using composite right/left-handed transmission lines," IEEE Trans. Microw. Theory Tech., Vol. 55, No. 6, 1341-1347, 2007.
doi:10.1109/TMTT.2007.895236

24. Ooi, B. Z. M., S. W. Lee, and B. K. Chung, "EVM measurements using orthogonal separation at the output of a non-linear amplifier," IET Microwaves, Antennas & Propagation, Vol. 6, No. 7, 813-821, 2012.
doi:10.1049/iet-map.2011.0390

25. Jung, S.-C. and O. Hammi, "Design optimization and DPD linearization of GaN-based unsymmetrical Doherty power amplifiers for 3G multicarrier applications," IEEE Trans. Microw. Theory Tech., Vol. 57, No. 9, 2105-2113, 2009.
doi:10.1109/TMTT.2009.2027076

26. Markos, A. Z., K. Bathich, F. GÄolden, and G. Boeck, "A 50W unsymmetrical GaN Doherty amplifier for LTE applications," 2010 European Microwave Conference (EuMC), 994-997, 2010.

27. Zhao, S., Z. Tang, Y. Wu, and L. Bao, "Linearity improved Doherty power amplifier using coupled-lines and a capacitive load," IEEE Microwave and Wireless Components Letters, Vol. 21, No. 4, 221-223, 2011.
doi:10.1109/LMWC.2011.2115970

Dr. Yunxuan Feng

Dr. Yuan'an Liu

Dr. Cuiping Yu

Dr. Shulan Li

Dr. Jiuchao Li

Dr. Xuan Zheng