This document summarizes a project to simulate a class F power amplifier operating at 2.4 GHz using ADS software. The objectives were to achieve over 50% power added efficiency and output power over 30 dBm. It provides background on power amplifiers and performance parameters. It describes the simulation steps taken, including DC analysis, stability analysis, load pull analysis, and impedance matching. The simulations achieved 62% power added efficiency and 33 dBm output power. Future work and conclusions are also presented.

1. Under the guidance of
Dr. Priyanka Mondal
Major Project Presented by
Abhishek kumar(1304010)
Krishna kumar(1304035)
Prashant shekhar(1304038)
Efficiency Improvement of A High
Power Amplifier
Electronics and communication Engineering
NATIONAL INSTITUTE OF TECHNOLOGY PATNA

2. Contents
• Objective
• Introduction
• Performance Parameters
• Literature Survey
• Classification of Power Amplifier(PA)
• Stability of PA
• Load Pull Analysis
• Simulation Steps And Results
• Future Scope
• Conclusion
• References

3. Objective
• Simulation of class F power amplifier using
ADS.
• Operating frequency is 2.4 GHz.
• We are targeting power added efficiency more
than 50%.
• We are targeting output power more than 30
dBm.

4. High Power Amplifier
• It is an electronic device used to amplify a low power,
radio frequency signal to relatively larger power signal.
• It allows us to convert DC power into electromagnetic
power.
Information
source
Modulator
r
Mixer
Power
amplifier
Block diagram of transmitter

5. Performance Parameters
• Efficiency
= PRF out/PDC
• Power added efficiency(PAE)
PAE= (PRF out - PRF in)/PDC
• Figure of merit
FOM= Pdis/PRF out
• Gain
G= 10*Log(Pout/Pin) db


6. Literature Survey
PA
Class
Technology Frequency
(GHz)
Pout
(dbm)
PAE
D GaAs HBT 0.700 29.5 78.5%
D GaN HEMT 0.900 44.5 75.0%
D GaN HEMT 2.140 47.0 62.7%
PA
Class
Technology Frequency
(GHz)
Pout
(dbm)
PAE
E GaN HEMT 2.000 40.5 74.0%
E GaAs FET 2.300 22.0 69.0%
E GaAs HEMT 3.500 23.0 65.0%
Title- Comparative Study of Recent Advances in Power Amplification Devices
Author-Oualid Hammi, and Fadhel M. Ghannouchi
Publication-IEEE Transaction on power amplifier 6 September 2009

7. Continued
PA
Class
Technology Frequency
(GHz)
Pout
(dbm)
Power added
Efficiency
F GaAs pHEMT 2.00 20.0 70.5%
F LDMOS FET 1.00 41.2 73.7%
F GaAs pHEMT 2.45 23.0 80.0%
F GaN HEMT 2.00 42.5 87.0%
Recent Performances of class F RF power amplifiers
Conclusion- Class F is more efficient at higher frequency

8. Continued
Title-Maximum efficiency and output of class F power amplifier
Author-Frederick H. Raab
Publication- IEEE transactions on microwave theory and techniques, June 2001
Abstract-A class F power amplifier (PA) improves efficiency and power output capability
by using selected harmonics to shape its drain-voltage and drain-current
waveforms.
Conclusion-we can get 100% efficiency ,if we can controlled infinite number of harmonic.
Title-GaN HEMT based Class F power amplifier with broad bandwidth and high efficiency
Author-Mustazar Iqbal ,Anna Piacibello
Publication-IEEE international conference on integrated circuits and microsystems,2016.
Abstract-Design and realisation of a highly efficient broadband class F PA with a multi
harmonic controlled output network over target frequency between 1.1-2.1
GHz.
Conclusion-The fabricated PA can achieve up to 60-73% efficiency.

9. Classification of Power Amplifier
PA classes Conduction angle Efficiency
Class-A 2π 50%
Class-B π 78%
Class-AB π < Ɵ < 2π 78%
Class-C 0< Ɵ < π 90%
Class-D 0< Ɵ < π/2 100%
Class-E 0< Ɵ < π/2 100%
Class-F slightly greater
than π
100%

10. Class F
• Harmonics generated due to switching nature.
• Harmonics must be controlled to boost efficiency.
• Voltage waveform at drain should appear to be perfect square.
• Current waveform should be half sine wave which is 180° out of
phase with voltage waveform at drain of transistor .

11. Operating Point of Class F
DI
DSV

12. Stability of Power Amplifier
• Conditional stability
• Un-conditional stability

13. The Stability Circles
S12S21
2 2
S22
Lr 
 
 22

11
2 2
S22
CL 
S  S

 
• Output Stability Circle ( L values for  1 )in
 Center
 Radius
 1in
CL
rL
CL
L -plane
S12S21
2 2
S11
sr 
 
 11 22
2 2
S11
 Center Cs 
S  S

 
• Input Stability Circle ( s values for  1 )
 Radius
out  1out
Cs
rs
Cs
s -plane

14. Load Pull Analysis
• Vary impedance presented to DUT.
• Measure parameter (power, gain…).
• Determine best matching impedance.
• Design matching network (using ADS).
Max power point
- 1 dB

15. Simulation Steps
• DC analysis
• Bias and stability
• Load pull analysis
• High PA design
• Impedance matching

16. Transistor Model
ATF53189 model transistor from Avago Technology

17. DC Analysis

18. Simulated DC Result

19. Bias & Stability

20. Simulated Stability Factor

21. S-Parameter On Bias Point

22. Simulated Stability Circles

23. Load Pull Analysis

24. Simulated Result of Load Pull

25. High PA (Class F)

26. PAE Relative To 50 Ohm

27. Simulated Waveform For 50 Ohm

28. Relative to complex output Impedance
PAE Relative To Complex Impedance

29. Waveform For Complex Impedance

30. Impedance Matching

31. PAE After Matching

32. Future Scope
• We can increase power added efficiency (PAE)
by adding more harmonics at drain output of
transistor.
• By controlling more harmonics we can also
increase gain because output power will be
increase.
• We can also improve PAE by changing various
parameter of transistor.

33. Conclusion
• Class F power amplifiers offer a significant
improvement in transmitter efficiency over other
designs.
• We have improved power added efficiency from
39% to 62% by changing 50 ohm standard
impedance to complex impedance.
• We have achieved output power 33 dBm from
input power 18 dBm after designing and
matching.

34. References
[1] P. Colantonio, F. Giannini, E. Limiti, “High efficiency RF and microwave
solid state power amplifier”, John Wiley & Sons, Ltd, 2009
[2] Steve C. Cripps, RF power amplifier for wireless comm.(2nd edition) ,artech
house microwave library
[3] Class D Audio Amplifier with Ferroxcube Gapped Toroid Output Filter,
Ferroxcube - Ferrite Cores, Bobbins & Accessories. Web. 13 May 2010.
[4] M. Hayati, A. Lotfi, M. Kazimierczuk, and H. Sekiya, “Performance
study of class-e power amplifier with a shunt inductor at subnominal
condition,” IEEE Trans. Power Electron., vol. 28, no. 8, pp. 3834–3844,
[5] F. H. Raab, “Maximum efficiency and output of Class-F power amplifiers”,
IEEE Transactions on Microwave Theory and Techniques, Vol. 49, No. 6,
June 2001

35. Continued
[6] F. H. Raab, “An introduction to Class-F power amplifiers,” RF Design, Vol.
19, No. 5, pp. 79-84, May 1996.
[7] N. Tuffy, G. Lei, Z. Anding, and T. J. Brazil, "A simplified broadband
design methodology for linearized high-efficiency continuous Class-F
power amplifiers," IEEE Trans. Microw. Theory Tech., vol. 60, pp. 1952-
1963, 2012.
[8] W. Ying, D. Shiwei, Y. Lisheng, L. Zhengjun, D. Yazhou, and F. Wenli,
"Design of high efficiency GaN HEMT class-F power amplifier at Sband,"in
Antennas and Propagation (APCAP), 2014 3rd Asia-Pacific Conference on,
2014, pp. 1157-1158.