On the class‐F power amplifier design

Power-amplifier class-F operation is investigated and revised, evidencing the fundamental importance of the harmonic-generating mechanism and the limitations imposed by the device input and output nonlinearities on the ideal class-F behavior. Closed-form expressions are derived for the major design quantities, together with the optimum fundamental and third-harmonic loading of the active device. A design procedure, making use of the derived expressions, is presented and the deviations from the ideal behavior are discussed. Sample designs, making use of a full nonlinear device model and commercial analysis software, are carried out to demonstrate the effectiveness of the analysis and the design procedure. It is shown, both analytically and using commercial nonlinear simulations, that blind application of commonly used, idealized class-F harmonic terminations can cause unexpected detrimental results. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 129–149, 1999

[1]  Franco Giannini,et al.  Class-AB Power Amplifier Design Guidelines , 1993, SBMO International Microwave Conference/Brazil,.

[2]  F. Raab.  Class-F power amplifiers with maximally flat waveforms , 1997 .

[3]  Franco Giannini,et al.  Harmonic‐loaded microwave power amplifiers: Nonlinear design procedure , 1995 .

[4]  Jose C. Pedro.  Evaluation of MESFET nonlinear intermodulation distortion reduction by channel-doping control , 1997 .

[5]  H. Kondoh.  FET power performance prediction using a linearized device model , 1989, IEEE MTT-S International Microwave Symposium Digest.

[6]  D. M. Snider,et al.  A theoretical analysis and experimental confirmation of the optimally loaded and overdriven RF power amplifier , 1967 .

[7]  T. Scott,et al.  Tuned Power Amplifiers , 1964 .

[8]  S. Ciorciolini,et al.  Novel non-linear equivalent circuit extraction scheme for microwave field-effect transistors , 1995, 1995 25th European Microwave Conference.

[9]  Franco Giannini,et al.  Direct-synthesis design technique for nonlinear microwave circuits , 1995 .

[10]  J. Obregon,et al.  High-efficient class F GaAs FET amplifiers operating with very low bias voltages for use in mobile telephones at 1.75 GHz , 1993, IEEE Microwave and Guided Wave Letters.

[11]  S. Toyoda.  High efficiency single and push-pull power amplifiers , 1993, 1993 IEEE MTT-S International Microwave Symposium Digest.

[12]  W. S. Kopp,et al.  High efficiency power amplification for microwave and millimeter frequencies , 1989, IEEE MTT-S International Microwave Symposium Digest.

[13]  B. Molnar.  Basic limitations on waveforms achievable in single-ended switching-mode tuned (Class E) power amplifiers , 1984 .