Highly efficient feed-forward amplifier employing a harmonic reaction amplifier

This paper proposes a new feed-forward amplifier configuration that employs a harmonic reaction amplifier as the main amplifier for high-efficiency operation. The fabricated 2-GHz band 20-W class feed-forward amplifier achieves the efficiency of 19.3% at the adjacent channel leakage power ratio of -45 dBc and the output power of 39 dBm using a W-CDMA test signal. The proposed feed-forward amplifier configuration achieves nearly 20% efficiency, which is the highest efficiency achieved by a 2-GHz band, 20-W class feed-forward amplifier for mobile communication systems.