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G. Magerl, Ch. Schuberth:
"Class F Amplifiers";
Talk: IEEE MTT-S International Microwave Symposium, Boston, MA, USA; 2009-06-07 - 2009-06-12; in: "Workshop Notes WSC (RFIC)", (2009).

The presentation starts with explaining the main ideas of optimizing power added efficiency of microwave power amplifiers. Class F operation is presented as one solution for achieving high efficiency together with high output power, however, at rather moderate gain. In a second step a more realistic picture of class F operation is drawn leading to third harmonic peaking amplifiers. Furthermore, bandwidth and linearity achievements in realistic Class F operation are treated. Finally, Class F amplifiers with substantially increased gain are presented. Class A gain in Class F operation can be achieved by driving the amplifier with non-sinusoidal signals. This leads to the concept of harmonic controlled amplifiers with even better power added efficiency than pure Class F. Again, examples of amplifiers are shown and their performance with respect to operational frequency, gain, and efficiency is discussed.