Experimental Implementation of Microwave Multi-Objective Linear Constrained Minimum Power Beamforming in the Near Field

We explore the use of a linear constrained minimum power (LCMP) algorithm for near-field beamforming and null forming for distributed phased arrays. Distributed array systems used in future microwave and millimeter-wave wireless communications, distributed sensing, and biomedical applications will necessitate the ability to focus energy and steer nulls in the near field of the array. We apply the traditional quiescent pattern constraint, which is a specialized form of the LCMP process for distortionless focusing at multiple desired locations or for simultaneous focusing and nulling. Experimental results demonstrate the ability to steer multiple beams or nulls to targets at 2.5 GHz using software-defined radios.