A harmonic controlled doherty power amplifier with enhanced efficiency at back-off power

This paper presents an efficiency enhanced Doherty power amplifier at 3.45 GHz for future communications. The carrier amplifier adopts harmonic controlled design strategy to obtain high efficiency. The transmission-line harmonic suppression network designed by using impedance buffer technique is employed to control the second and third harmonics. Measurement results show that drain efficiency of the proposed DPA can achieve higher than 55% at 6 dB back-off power at the operation frequency of 3.45 GHz, while the saturation power is larger than 49.5 dBm.