Multiobjective Distributed Array Beamforming in the Near Field Using Wireless Syntonization

Abstract

We demonstrate the efficacy of distributed microwave multiobjective beamforming at ranges near field to the array using an optimization algorithm and wireless frequency alignment (syntonization). While considerable research has recently been devoted to distributed phased array coordination, the ability to steer signals to locations close to the array in open-loop (feedback-free) systems has not been demonstrated. In this work, we apply a traditional far-field beamforming algorithm to a set of distributed antennas that are wirelessly syntonized. We demonstrate multiobjective beamforming at 0.9 GHz using software-defined radios (SDRs) in a distributed array steering either two beams (focii) or one beam and one null. This work demonstrates the feasibility of a critical part of future distributed beamforming systems that, when combined with other coordination technologies, will support coherent beamforming in widely distributed wireless systems.