Investigations of Active Antenna Doherty Power Amplifier Modules Under Beam-Steering Mismatch

This letter investigates the performance of a Doherty power amplifier (DPA) in an <inline-formula> <tex-math notation="LaTeX">$8\times 1$ </tex-math></inline-formula> active antenna transmitter module under an average voltage-standing-wave ratio of 4:1 induced by the array 1-D beam steering and mutual coupling. The GaN-based DPA and a <inline-formula> <tex-math notation="LaTeX">$2\times 1$ </tex-math></inline-formula> segment of the array are verified via measurements at the operating frequency of 3.5 GHz. The co-design and co-simulation of both the antenna array and the behavioral model of the DPA show that the inherent back-off efficiency benefit—when compared to traditionally used class-AB and -B amplifiers in base stations—can be maintained when restricting the beam-steering angle, in this case <inline-formula> <tex-math notation="LaTeX">$\theta \in $ </tex-math></inline-formula> [−45°, 45°], and operational bandwidth of the combined system.