Work

All-angle wideband acoustic self-collimation by Helmholtz resonators

Year: 2026

Type: article

Abstract: Phononic crystals and acoustic metamaterials have transformed acoustic wave control over the past three decades, enabling unprecedented manipulation of sound through tailored structural periodicity and local resonances. In this study, we demonstrate how Helmholtz resonators (HRs) embedded in square-lattice sonic crystals (SCs) achieve all-angle self-collimation (AASC) of acoustic waves across wide frequency ranges—a phenomenon previously attainable only with rectangular lattices or elliptical scatterers. Through finite element simulations, we analyze two types of Locally Resonant SCs (LRSCs) with different HR embedded scatterers: One with resonant frequency in the wavelength regime, classified as H R − T 2 and another with a lower local resonance frequency, termed as H R − T 1 . The H R − T 2 case exhibits wideband All-Angle Self-Collimation(AASC) in the third band, covering 66.5% of its bandwidth (520 Hz), while H R − T 1 shows frequency-sensitive super-collimation (FSSC) and AASC in the fourth band (22.86% bandwidth, 190 Hz). Frequency response analysis of finite supercell arrays validate robust collimation for incident angles up to 85°. Our findings highlight the unique ability of HRs to induce AASC in symmetric lattices, unlocking applications in directional sound control, low-loss acoustic waveguides, non-diffractive beam shaping, and high-resolution acoustic imaging systems.

Source: Results in Physics

DOI: 10.1016/j.rinp.2026.108575

Authors: David Ramírez-Solana, Muhammad Gulzari

Institution: University College Dublin

Language: English

Topic: Acoustic Wave Phenomena Research

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,920

Funder: Enterprise Ireland