An optimized Doherty power amplifier using an unequal quadrature input splitter

In this article, we present an optimized Doherty power amplifier using an unequal quadrature input splitter and bias control for the peaking amplifier. The linearity and efficiency performances of the Doherty power amplifier were experimentally optimized by means of unequal quadrature input power splitters, which drive unbalanced input power between the carrier and peaking amplifiers. The bias points of the peaking amplifier were also adjusted for each input splitter. A high power‐added efficiency of 33.68% and an output power of 33.95 dBm were achieved for a down‐link wide‐band code division multiple access signal excitation at a given adjacent channel leakage‐power ratio of −30 dBc. This was a significant improvement by 2.75% and 8.22% points from the conventional Doherty and class‐AB amplifiers, respectively. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1536–1539, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23420