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 8 x 1 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 2 x 1 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 theta is an element of [-45 degrees, 45 degrees], and operational bandwidth of the combined system.