Drain efficiency amplifier of 50% with optimized power range for CDMA base station

Abstract A novel high‐efficiency Doherty amplifier is presented here.A carrier amplifier and a peak amplifier are set to asymmetrical drain voltages to extend the power range where a high efficiency of the amplifier is maintained. In Doherty amplifier, matching circuits of the carrier amplifier and peak amplifier are designed for each drain voltage so that the efficiency and signal linearity of the amplifier at a 7.2 dB back‐off point from its saturated output power become higher than those of a conventional amplifier. A Doherty amplifier containing laterally‐diffused metal‐oxide semiconductor field‐effect transistors achieves an adjacent channel leakage power ratio of −30.89 dBc and a drain efficiency of 50% at an output power of 49.3 dBm. This is the highest drain efficiency of a Doherty amplifier for a CDMA signal to the best of the authors' knowledge. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1244–1246, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25195