Metagrating-based Single-pixel Acoustic Direction Finding

TL;DR

This work addresses acoustic direction finding with reduced hardware by introducing a metagrating-based single-pixel framework. A two-layer metagrating encodes incident fields into distinct diffraction-order patterns, enabling a compressive sensing formulation where a single sensor suffices to recover 360° directions. Numerical simulations and experimental validation show robust 360° localisation across frequencies and under noise, with a modest bandwidth requirement (e.g., 5.2 kHz) and reconstruction strengths remaining high. The approach offers a compact, low-cost, scalable alternative to traditional microphone arrays, with potential applications in industrial monitoring, target tracking, and non-destructive health sensing.

Abstract

Acoustic metamaterials provide new opportunities for compact and efficient wavefront manipulation, extending beyond conventional bulky and power-intensive phased-arrays. In this work, we exploit the spatial encoding properties of the acoustic metagrating aperture to transform incident acoustic fields into compressed measurements for single-pixel acoustic source localisation. The proposed method enables accurate direction finding of acoustic sources over both 180 and 360 degrees angular ranges. Numerical simulations confirm the robustness of the metagrating-based compressive sensing approach against noise and limited sampling. Experimental validation is conducted to verify its feasibility with practical metagrating prototyes. Compared wiith tranditional array-based localisation techniques, the single-pixel metagrating system significantly reduces hardward complexity while maintaining high localisation accuracy. These findings demonstrate the potential of integrating compressive sensing with acoustic metagratings for compact, low-cost, scalable source detection systems, with prospective applications in industrial monitoring, target tracking and non-destructive health monitoring.

Figures (4)

• Figure 1: Schematic diagram of the metagrating-based single-sensing system for source direction finding.
• Figure 2: Correlation of the proposed two-layer finite metagrating-encoder under monopole source excitation.
• Figure 3: Numerical results of a single source localization. (a) Without noise. (b) With Gaussian noise at SNR of 15dB.
• Figure 4: Experimental demonstration of single-pixel source direction finding. (a) Schematic experimental setup. (b) Experimental source angular direction finding performance across the full azimuthal range.