Near-Field Beampointing with Low Exposure Regions: a Dominant Subspace Projection Approach

TL;DR

This paper introduces a low-complexity, subspace-based beamforming algorithm for near-field antenna arrays that effectively targets a user while minimizing exposure in designated regions.

Contribution

It proposes a novel dominant subspace projection method to design near-field beam patterns with low computational complexity under exposure constraints.

Findings

Achieves near-optimal power at the target user.

Provides uniform power mitigation over low exposure regions.

Reduces computational complexity compared to traditional methods.

Abstract

The spherical nature of the wavefronts exhibited in the near-field of antenna arrays enables advanced beamforming capabilities, such as beampointing and beamnulling. In this paper, we exploit these properties to design a near-field beam pattern under a low exposure region constraint. We address the continuous region constraint through spatial discretization, which results in a large number of constraints that lead to prohibitive computational complexity. We propose a novel low-complexity algorithm that enables a computationally tractable beam pattern design. It uses a low-dimensional subspace representation of the low exposure region based on a singular value decomposition. Our approach achieves low complexity while providing a power received at a target user close to the optimal achievable power, yet with uniform power mitigation over the low exposure region.