Near Field Tapering with Slepian Window: Balancing the Range Angle Sidelobe Trade off

TL;DR

This paper introduces a Slepian window-based tapering method for near-field beamforming that effectively reduces sidelobes in both range and angle dimensions, enhancing target detection amidst interference.

Contribution

It presents a novel Slepian amplitude tapering technique tailored for near-field scenarios, outperforming traditional methods in sidelobe suppression.

Findings

Peak sidelobe suppression improved by ~24 dB laterally.

Axial sidelobe suppression improved by ~10 dB.

Method enhances target discrimination in near-field applications.

Abstract

Near-field beamforming enables target discrimination in both range (axial) and angle (lateral) dimensions. Elevated sidelobes along either dimension, however, increase susceptibility to interference and degrade detection performance. Conventional amplitude tapering techniques, designed for far-field scenarios, cannot simultaneously suppress axial and lateral sidelobes in near-field. In this letter, we propose a Slepian-based amplitude tapering approach that maximizes mainlobe energy concentration, achieving significant sidelobe reduction in both dimensions. Numerical results show that the proposed taper improves peak sidelobe suppression by approximately 24 dB in the lateral domain and 10 dB in the axial domain compared to a conventional uniform window.