A novel power dependent input distribution network for Doherty amplifier efficiency improvement

Abstract

This paper researches on the effect of input network on performance of power added efficiency (PAE) in a Doherty circuit. A new technique based on an adaptive input-power distribution is introduced to overcome the limitations of practical Doherty power amplifiers. The extended-resonance divider is designed by exploiting the peaking amplifier's nonlinear input impedance, so that more power can be delivered to the carrier and peaking amplifiers in the low and high power regions, respectively. Therefore, the two amplifiers are efficiently driven and can generate output current and voltage characteristics similar to the ideal Doherty amplifier. The PAE of the new Doherty amplifier is improved by 2%-3% compared with a conventional design through simulations as a result.