A Doherty power amplifier based on a tapered line impedance inverter

Abstract

This paper presents a wideband GaN Doherty power amplifier (DPA) in the 2.6 GHz band with a 3 stages Wilkinson splitter where the impedance inverter is based on a tapered line instead of a quarter wave transformer. From the comparison with the same amplifier using a typical quarter-wave transformer as impedance inverter, and keeping both designs the same bandwidth (1.6 to 3.3 GHz, 65% of the fractional bandwidth), the Power Added Efficiency (PAE) is enhanced up to 50% (from 40.46% to 61.17% at 35 dBm input power) in the DPA with a tapered line. Besides, the transducer gain remains practically unaltered.