Stealth and equiluminous materials for scattering cancellation and wave diffusion

TL;DR

This paper presents a method to design 2D acoustic materials with tailored scattering properties, enabling broadband backscattering suppression or uniform scattering intensity, validated through theoretical and numerical analysis.

Contribution

A novel procedure for designing 2D acoustic structures with prescribed scattering patterns based on reciprocal space targeting.

Findings

Designed stealth acoustic materials with broadband backscattering suppression.

Created equiluminous materials with uniform broadband scattering.

Validated scattering properties with excellent agreement between models.

Abstract

We report a procedure to design 2-dimensional acoustic structures with prescribed scattering properties. The structures are designed from targeted properties in the reciprocal space so that their structure factors, i.e., their scattering patterns under the Born approximation, exactly follow the desired scattering properties for a set of wavelengths. The structures are made of a distribution of rigid circular cross-sectional cylinders embedded in air. We demonstrate the efficiency of the procedure by designing 2-dimensional stealth acoustic materials with broadband backscattering suppression independent of the angle of incidence and equiluminous acoustic materials exhibiting broadband scattering of equal intensity also independent of the angle of incidence. The scattering intensities are described in terms of both single and multiple scattering formalisms, showing excellent agreement with each other, thus validating the scattering properties of each material.