Digitally virtualized atoms for acoustic metamaterials

TL;DR

This paper introduces a novel concept of virtualized acoustic metamaterials using digital signal processing, enabling dynamic, software-controlled tuning of material properties without physical structural modifications.

Contribution

It proposes replacing physical resonator structures with digital convolution kernels, allowing independent and real-time control of bulk modulus and density in metamaterials.

Findings

Decoupled control of bulk modulus and density achieved digitally

Reconfigurable amplitude, frequency, bandwidth, and phase delay in real-time

Potential for time-varying and adaptive metamaterials

Abstract

By designing tailor-made resonance modes with structured atoms, metamaterials allow us to obtain constitutive parameters outside their limited range from natural or composite materials. Nonetheless, tuning the constitutive parameters relies much on our capability in modifying the physical structures or media in constructing the metamaterial atoms, posing a fundamental challenge to the range of tunability in many real-time applications. Here, we propose a completely new notion of virtualized metamaterials to lift the traditional boundary inherent to the physical structure of a metamaterial atom. By replacing the resonating physical structure with a designer mathematical convolution kernel with a fast digital signal processing circuit, we show that a decoupled control of the effective bulk modulus and density of the metamaterial is possible on-demand through a software-defined frequency dispersion. Purely noninterfering to the incident wave in the off-mode operation while providing freely reconfigurable amplitude, center frequency, bandwidth, and phase delay of frequency dispersion in on-mode, our approach adds an additional dimension to wave molding and can work as an essential building block for time-varying metamaterials.