Multilateral Sound Manipulation Using Magnetically Tunable Apertures

• Published in: Advanced engineering materials Vol. 26; no. 5
• Main Authors: Bansal, Shubhi, Choi, Christabel, Subramanian, Sriram
• Format: Journal Article
• Language: English
• Published: 01.03.2024
• Subjects: acoustic devices; magnetic actuation; sound wave manipulation; tunable apertures
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.202301339

In recent years, planar aperture‐based acoustic devices have been investigated due to their thin form factor, high effective transmission, and sound modulation capability. Moreover, reconfigurable and tunable devices are being continuously researched to enable multiple degrees of freedom in real time. Herein, an aperture‐based acoustic device is presented, which enables tunable multilateral ultrasonic operation. Sound waves are manipulated in multiple directions by continuously tuning aperture width or length, using a magnetically controlled rod. The position, orientation, and geometrical properties of the rod (i.e., length, topographical curvature) are exploited to create a varied interface for the impinging sound. Through experiments and simulations, acoustic wave steering in different orthogonal planes and acoustic switching using a single tunable device unit are demonstrated. Furthermore, different four‐unit device configurations are implemented for tunable beam‐formation and tunable acoustic focusing applications by utilizing the acoustic anisotropy of the system. The tunable dynamic acoustic device is scalable to audible frequencies and enables tilted operation. This straightforward and accessible proof‐of‐concept opens a paradigm for exploring multifunctional aperture‐based designs with greater degrees of freedom, bringing us a step closer toward practical applications such as acoustic device integration with walls, window panels, and other commercial products for tunable sound transmission. A subwavelength aperture is magnetically tuned on‐demand with a cylindrical rod for multilateral manipulation of acoustic waves. Acoustic anisotropy is achieved through the placement and orientation of the cylindrical rod relative to the aperture. Using a single aperture, acoustic switching and acoustic wave steering in different orthogonal planes are demonstrated. Subsequently, tunable beams and foci with multiaperture configurations are generated.