A Doherty power amplifier with an improved π-type output network

Abstract

In this paper, works are focused on the impact of output network on PAE (power-added-efficiency) performance of a Doherty circuit. A shunt capacitor π-network is put forward to improve the output network of Doherty amplifier, based on the equivalent quarter wavelength transmission line. The analysis for this amplifier is presented. A Doherty circuit with applying the improved output network is designed, fabricated and tested. The device used is MRF6S21050L LDMOS. The PAE tested of the Doherty circuit gets 2% improvement in the power backoff region. When ACLR is -30dBc, the corresponding output power measured is 43.5dBm and the drain efficiency measured is 45.75%. All these measured data show very good agreements with the simulated ones.