1. Steer, M., "Beyond 3G," IEEE Microw. Mag., Vol. 8, No. 1, 76-82, 2007.
2. Raab, F. H., P. Asbeck, S. Cripps, P. B. Kenington, Z. B. Popovic, N. Pothecary, J. F. Sevic, and N. O. Sokal, "Power amplifiers and transmitters for RF and microwave," IEEE Trans. Microw. Theory Tech., Vol. 50, No. 3, 814-826, 2002.
doi:10.1109/22.989965
3. Raab, F. H., "Effciency of Doherty RF power-amplifier systems," IEEE Trans. on Broadcasting, Vol. 33, No. 3, 77-83, 1987.
doi:10.1109/TBC.1987.266625
4. Cripps, S. C., "Doherty and Chireix," Advanced Techniques in RF Power Amplifier Designs, 33-72, 2002.
5. Kim, B., J. Kim, I. Kim, and J. Cha, "The Doherty power amplifier," IEEE Microw. Mag., Vol. 7, No. 5, 42-50, 2006.
doi:10.1109/MW-M.2006.247914
6. Lee, Y. S., M. W. Lee, and Y. H. Jeong, "A highly linear and effcient two-stage GaN HEMT asymmetrical Doherty amplifier for WCDMA applications," Microwave and Optical Technology Letters, Vol. 51, No. 6, 1464-1467, 2009.
doi:10.1002/mop.24387
7. Lee, Y., M. Lee, and Y. Jeong, "Unequal-cells-based GaN HEMT Doherty amplifier with an extended effciency range," IEEE Microw. Wireless Compon. Lett., Vol. 18, No. 8, 536-538, 2008.
doi:10.1109/LMWC.2008.2001015
8. Kim, J., B. Fehri, S. Boumaiza, and J. Wood, "Power effciency and linearity enhancement using optimized asymmetrical Doherty power amplifiers," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 1, 425-434, 2011.
doi:10.1109/TMTT.2010.2086466
9. Moon, J., J. Kim, I. Kim, J. Kim, and B. Kim, "A wideband envelope tracking Doherty amplifier for WiMAX systems," IEEE Microw. Wireless Compon. Lett., Vol. 18, No. 1, 49-51, 2008.
doi:10.1109/LMWC.2007.912019
10. Lee, M. W., S. H. Kam, Y. S. Lee, and Y. H. Jeong, "A highly effcient three-stage Doherty power amplifier with flat gain for WCDMA applications," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 17--18, 2537-2545, 2010.
doi:10.1163/156939310793675619
11. Feng, Y., Y. Liu, C. Yu, S. Li, J. Li, and X. Zheng , "Design of linearity improved asymmetrical GaN Doherty power amplifier using composite right/left-handed transmission lines," Progress In Electromagnetics Research B, Vol. 53, 89-106, 2013.
12. Zhou, R. W., Y. Dong, and J. F. Bao, "A 460MHz Doherty amplifier for IMT-advanced system," Progress In Electromagnetics Research Letters, Vol. 32, 187-195, 2012.
13. Wu, D. Y. and S. Boumaiza, "A modified Doherty configuration for broadband amplification using symmetrical devices," IEEE Trans. Microw. Theory Tech., Vol. 60, No. 10, 3201-3213, 2012.
doi:10.1109/TMTT.2012.2209446
14. Darraji, R., F. M. Ghannouchi, and M. Helaoui, "Mitigation of bandwidth limitation in wireless Doherty amplifiers with substantial bandwidth enhancement using digital techniques," IEEE Trans. Microw. Theory Tech., Vol. 60, No. 9, 2875-2885, 2012.
doi:10.1109/TMTT.2012.2207910
15. Kang, D., D. Kim, Y. Cho, B. Park, J. Kim, and B. Kim, "Design of bandwidth-enhanced Doherty power amplifiers for handset applications," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 12, 3474-3483, 2011.
doi:10.1109/TMTT.2011.2171042
16. Sarkeshi, M., O. B. Leong, and A. Van Roermund, "A novel Doherty amplifier for enhanced load modulation and higher bandwidth," IEEE MTT-S Int. Microw. Symp. Dig., 763-766, 2008.
17. Qureshi, J. H., N. Li, W. C. E. Neo, F. van Rijs, I. Blednov, and L. C. N. de Vreede, "A wide-band 20W LDMOS Doherty power amplifier," IEEE MTT-S Int. Microw. Symp. Dig., 1504-1507, 2010.
18. Bathich, K., A. Z. Markos, and G. Boeck, "A wideband GaN Doherty amplifier with 35% fractional bandwidth," Proc. 40th Eur. Microw. Conf., 1006-1009, 2010.
19. Bathich, K., A. Z. Markos, and G. Boeck, "Frequency response analysis and bandwidth extension of the Doherty amplifier," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 4, 934-944, 2011.
doi:10.1109/TMTT.2010.2098040
20. Kang, D., D. Kim, J. Moon, and B. Kim, "Broadband HBT Doherty power amplifiers for handset applications," IEEE Trans. Microw. Theory Tech., Vol. 58, No. 12, 4031-4039, 2010.
21. Sun, G. and R. H. Jansen, "Broadband Doherty power amplifier via real frequency technique," IEEE Trans. Microw. Theory Tech. , Vol. 60, No. 1, 99-111, 2012.
doi:10.1109/TMTT.2011.2175237
22. Gustafsson, D., C. M. Andersson, and C. Fager, "A modified Doherty power amplifier with extended bandwidth and reconfig- urable effciency," IEEE Trans. Microw. Theory Tech., Vol. 61, No. 1, 533-542, 2013.
doi:10.1109/TMTT.2012.2227783
23. Pozar, D. M., "Tapered lines," Microwave Engineering, 255-261, 2005.
24. Lin, S. and A. E. Fathy, "Development of a wideband highly effcient GaN VMCD VHF/UHF power amplifier," Progress In Electromagnetics Research C, Vol. 19, 135-147, 2011.