Doherty power amplifier for WiMAX base stations designed using filtering approach to improve PAE

1. Doherty Power Amplifier at 2.4 GHz to
improve harmonic response using filter
characteristics
Ajinkya C. Kulkarni
ajinkyackulkarni@gmail.com

2. Outline: Concept
Carrier
Amplifier
Peaking
Amplifier
PowerSplitter Offset Lines
QuarterWave
Transformer
Load
Quarter Wave
Transformer
Input
Output

3. Amplifiers used in cellular base stations
[3] R. Giofrè, L. Piazzon, P. Colantonio and F. Giannini, “Being Seventy-Five Still Young: The Doherty Power Amplifier,”
Microwave Journal, April 2012, pp. 72-88.
[4] Bumman Kim, Jangheon Kim, Ildu Kim, and Jeonghyeon Cha, “The Doherty Power Amplifier,” IEEE Microwave
Magazine, Oct. 2006, pp. 42-50. [5]
Pre
2003
2003-
2005
2005 2010
2010-
Present
Feed-forward
Class AB
Class AB with DPD
Doherty with memory
based DPD
Enhanced Video
bandwidth
Doherty and its
novel approaches

4. Doherty Power Amplifier
[6] W. H. Doherty, “New High Efficiency Power Amplifier for Modulated Waves,” Proceedings of Institute of Radio
Engineers, vol.24, no.9, pp. 1163-1182, Sept.1936
[3] and Internet Source: http://en.wikipedia.org/wiki/Doherty_amplifier
Aug 21, 1907 - Feb 15, 2000
• Invented by William H. Doherty at Bell Labs in
1936
• Originally, class B carrier and class B peaking
amps (both tubes, of course, its 1930’s)
• Later modified by Joseph B. Sainton of Continental
Microwave, giving it a form it today has.

5. Doherty Amplifier Architecture
Carrier Amplifier
Peaking Amplifier
PowerSplitter Offset Lines
QuarterWave
Transformer
Load
Quarter Wave
Transformer
Input
Output
Low power: peaking amp pinched off, representing open circuit at recombination point
High power: carrier amp remains saturated, peaking adapts load and reaches max
efficiency
Typically class C
Typically class AB

6. Doherty Amplifier operation
[7] Joongjin Nam, Jin-Ho Shin, and Bumman Kim, “A Handset Power Amplifier With High Efficiency at a
Low Level Using Load-Modulation Technique,” IEEE Transactions on Microwave Theory and Techniques,
vol. 53, no. 8, August 2005, pp. 2639-2644. [4] and [8]
Doherty Amplifier
working can be
explained using load
modulation
principle.
Fig. Reproduced from: [7]

7. Device Selection: CGH40010, GaN HEMT:
Large Signal Model
[38], [41], [42]
[43] Kazutaka Inoue et al., “High Power and High Efficiency GaN-HEMT for Microwave
Communication Applications,” IMWS-IWPT2011 Proceedings, pp. 267-270.

8. Doherty power amplifier design: 50:50 power split
ratio
Ref. [55]

9. Inverted Doherty Power Amplifier
Carrier
Amplifier
PowerSplitter
Offset Lines
QuarterWave
Transformer
Load
Quarter Wave
Transformer
Input
Output
Peaking
Amplifier
[56] Karun Rawat , Fadhel Ghannouchi, “Load-pull Assisted CAD Design of Inverted Doherty Amplifier without Quarter-
wave Transformer,” presented at 25th IEEE Canadian Conference on Electrical and Computer Engineering (CCECE), 2012.

10. Selected Amplifier: Inverted Doherty Power
Amplifier: 70:30 power split ratio

11. Designing the Layout

12. Measurement Set Up

13. Response from the amplifier: Signal Spectrum

14. Response from the amplifier: C/N ratio

15. Response from the amplifier: Small signal gain

16. References 1
1. Frank Amoroso, “Spectral Sidelobe Regrowth in Saturating Amplifiers,” Applied Microwave and
Wireless, March 1998, pp. 36-42.
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Issues and Challenges,” Communication Surveys and Tutorials, IEEE, vol.13, no.4, pp. 524-540, Fourth
Quarter 2011.
3. R. Giofrè, L. Piazzon, P. Colantonio and F. Giannini, “Being Seventy-Five Still Young: The Doherty
Power Amplifier,” Microwave Journal, April 2012, pp. 72-88.
4. Bumman Kim, Jangheon Kim, Ildu Kim, and Jeonghyeon Cha, “The Doherty Power Amplifier,” IEEE
Microwave Magazine, Oct. 2006, pp. 42-50.
5. Damon Holmes, “Doherty Power Amplifier Theory and Design for Cellular Infrastructure Applications,”
presented at EDI CON 2013, Beijing China.
6. W. H. Doherty, “New High Efficiency Power Amplifier for Modulated Waves,” Proceedings of Institute
of Radio Engineers, vol.24, no.9, pp. 1163-1182, Sept.1936.
7. Joongjin Nam, Jin-Ho Shin, and Bumman Kim, “A Handset Power Amplifier With High Efficiency at a
Low Level Using Load-Modulation Technique,” IEEE Transactions on Microwave Theory and
Techniques, vol. 53, no. 8, August 2005, pp. 2639-2644.
8. Paolo Colantonio, Franco Giannini, and Ernesto Limiti, High Efficiency RF and Microwave Solid State
Power Amplifiers, A John Wiley and Sons Ltd., Publication, 2009, pp. 131-160.
9. Christopher Burns, “Highly efficient amplifier shows the promise of Doherty architecture.” Internet:
www.rfdesign.com [June 2007]
10. Bumman Kim, Ildu Kim, and Junghwan Moon, “Advanced Doherty Architecture,” IEEE Microwave
Magazine, August 2010, pp. 72-86.

17. References 2
11. R. Giofrè, L. Piazzon, P. Colantonio and F. Giannini, “Being Seventy-Five Still Young: The Doherty Power
Amplifier,” Microwave Journal, April 2012, pp. 72-88.
12. P. Colantonio, F. Giannini, R. Giofrè and L. Piazzon, “The Doherty Power Amplifier,” International Journal of
Microwave and Optical Technology, vol.5, no.6, November 2010, 415-430.
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vol. BC-33, no. 3, September 1987, pp. 77-83.
14. Youngoo Yang, Jaehyok Yi, Young Yun Woo, and Bumman Kim, “Experimental Investigation on Efficiency and
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International, 2001, vol. 2, pp. 1367-1370.
15. Bumman Kim, Jangheon Kim, Ildu Kim, and Jeonghyeon Cha, “The Doherty Power Amplifier,” IEEE
Microwave Magazine, Oct. 2006, pp. 42-50.
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Microwave Circuits and Systems, InTech Publishers, pp.107-132.
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2011.
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Amplifier,” RF Micro Devices Chandler, AZ, Feb. 2012.
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Amplifier,” IEEE Microwave and Wireless Components Letters, vol. 18, no. 3, March 2008, pp. 197-199.
20. JorgeMorenoRubio et al., “ A 22 W 65% efficiency GaN Doherty power amplifier at 3.5GHz for WiMAX
applications,” IEEE Integrated Nonlinear Microwave and Millimetre-wave Circuits (INMMiC 2011), April 18th -
19th, 2011 in Vienna, Austria.

18. References 3
21. Kenle Chen et al., “Design of Adaptive Highly Efficient GaN Power Amplifier for Octave-Bandwidth
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Line,” Proceedings of the 36th European Microwave Conference, Sept. 2006, Manchester UK.
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Base Station Power Amplifiers,” 35th Europian Microwave Conference, 2005, Paris, pp. 963-966.
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and Wireless Components Letters, vol. 20, no. 2, February 2010, pp. 109-111.
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Applications,” High Frequency Electronics, May 2009, pp. 36-48.
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Band,” MIKON 2012, 19th International Conference on Microwaves, Radar and Wireless Communications,
Warsaw, Poland, 21-23 May, 2012, pp. 186-189.
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Electromagnetics Research Letters, vol. 32, June 2012, pp.187-195.
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Symposium Digest (MTT), 2010 IEEE MTT-S International, 23 28 May, 2010, pp. 1086-1089.
30. Junghwan Moon, Jangheon Kim, Ildu Kim, Jungjoon Kim, and Bumman Kim, “Highly Efficient Three-Way
Saturated Doherty Amplifier With Digital Feedback Predistortion,” IEEE Microwave and Wireless Components
Letters, vol. 18, no. 8, August 2008, pp. 539-541.

19. References 4
31. Asdesach Z. Markos and GUnter Kompa, “High Power Doherty Amplifier Design for UMTS Application,” Microwave
Conference (GeMIC), 2008, German, 10-12 March, 2008, pp. 1-4.
32. Craig Steinbeiser, Thomas Landon, Charles Suckling, “250W HVHBT Doherty with 57% WCDMA Efficiency
Linearized to -55dBc for 2c11 6.5dB PAR,” Compound Semiconductor Integrated Circuit Symposium, CSIC 2007,
IEEE, 14-17 Oct., 2007, pp. 1-4.
33. Ildu Kiml, and Bumman Kim, “A 2.655 GHz 3-stage Doherty Power Amplifier using Envelope Tracking Technique,”
Microwave Symposium Digest (MTT), 2010 IEEE MTT-S International, 23-28 May, 2010, pp. 1496-1498.
34. Hiroaki Deguchi, Norihiko Ui, Kaname Ebihara, Kazutaka Inoue, Norihiro Yoshimura and Hidenori Takahashi, “A 33W
GaN HEMT Doherty Amplifier with 55% Drain Efficiency for 2.6GHz Base Stations,” Microwave Symposium Digest
(MTT), 2009 IEEE MTT-S International, 7-12 June, 2009, pp. 1273-1276.
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20. References 5
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Applications,” IMWS-IWPT2011 Proceedings, pp. 267-270.
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22. Thank you!