Complementary Acoustic Metamaterial for Penetrating Aberration Layers

Abstract

Impedance-matched acoustic materials were developed to improve ultrasound penetration through the aberration layer. The traditional ultrasound layer matching material is called a couplant, which can only enhance ultrasound transmission to soft biological media such as the cartilage and muscle but cannot penetrate hard media such as the bone. Here, we propose a phasemodulated complementary acoustic metamaterial based on the principle of impedance matching, which enables ultrasound to penetrate the bone, and use the equivalent parameter technology of acoustic metamaterials for parameter design. Ultrasonic layer adjustment is performed through 3D printing and corrects bone aberrations. Several configurations were investigated through numerical simulations and experiments in non-reflecting tanks. Specifically, the bone matching layer can be optimally designed for a specific bone thickness and a specific operating frequency of the ultrasound probe, thereby amplifying the ultrasound to penetrate the matching layer and bone. The experimental and simulation results show that the proposed acoustic metamaterial can improve the transmission efficiency of ultrasound through the aberration layer.

Void-Engineered Metamaterial Delay Line with Built-In Impedance Matching for Ultrasonic Applications

“…Recent advances in additive manufacturing have greatly enhanced the ability to fabricate acoustic metamaterials [15,16]. The problem of acoustic impedance mismatch has also started to be addressed by various groups using acoustic metamaterials [17][18][19][20]. Research work by [7,21,22] showed that graded impedance matching metamaterials can improve broadband energy transmission in high frequency (1-5 MHz) applications.…”

Enhanced Ultrasound Transmission through Skull Using Flexible Matching Layer with Gradual Acoustic Impedance

“…For instance, Shen et al theoretically designed a complementary acoustic metamaterial (CMM) that effectively weakens the aberrating layer of the skull, resulting in enhanced transmission and reduced acoustic field distortion . Recently, Li et al proposed a phase-modulated complementary acoustic metamaterial (PCMM) to counteract the effects of impedance mismatches . Although the simulation and experimental results are encouraging, these metamaterial structures are often complex and rigid, requiring customization for different skull shapes and different frequencies.…”

Acoustic metamaterials based on polymer sheets: from material design to applications as sound insulators and vibration dampers

“…The mass density ρ and the bulk modulus κ are the key constitutive parameters that affect sound waves in AMMs, and they correspond to the dielectric constant ϵ and magnetic permeability μ in electromagnetic metamaterials, respectively. Through the implementation of AMMs for two decades, unique physical phenomena and functions, which cannot be achieved by only modifying material properties, have been demonstrated [9][10][11][12][13][14][15][16].…”