3D Beamforming Method for Near-Field-Focused Active Phased Array: 3D Scanning and 3D Polarization Manipulating

The near-field-focused (NFF) beam design is a nonlinear 3D problem, which is significantly different with the far-field case. In this paper, a method of 3D beamforming, i.e., 3D polarization manipulating and 3D scanning, of the NFF phased array is proposed. The near-field (NF) 3D polarization manipulation is realized through vector synthesis of orthogonal polarization elements. A machine learning method is employed to build the amplitude and phase prediction model of the NFF phased-array antenna, which can solve the focal shift problem and realize the instant and accurate 3D scanning of the focus. The proposed 3D beamforming method is verified with a millimeter-wave NF-focusing active phased array prototype.