Design and characterization of a 1.7–2.7 GHz quasi-MMIC Doherty power amplifier

This paper presents the design and characterization of a Doherty power amplifier for small cells applications in the 1.7-2.7 GHz band. A quasi-monolithic realization is chosen for its cost advantages when compared to a fully-monolithic solution, and relies on GaN HEMT active devices, but passive networks realized on GaAs substrate. A lumped element Doherty combiner is designed to maximize the bandwidth at which the power amplifier shows high back-off efficiency that results higher than 37% in the 1.7-2.7 GHz band. The dual-input topology permits high flexibility in the optimization of performance, in particular in terms of bandwidth. The fabricated Doherty favourably compares to previously published power amplifiers.