Broadband acoustic illusion coating based on thin conformal metasurface

Area of Science:

• Acoustic Metasurfaces
• Wavefront Manipulation
• Acoustic Cloaking

Background:

• Acoustic illusion carpets reshape scattering waves but are limited by narrow bandwidth and large volume.
• Existing technologies struggle to achieve efficient acoustic cloaking over broad frequency ranges.

Purpose of the Study:

• To propose and demonstrate broadband conformal acoustic illusion coatings.
• To overcome the bandwidth and volume limitations of traditional acoustic illusion carpets.

Main Methods:

• Designed subwavelength-thick metacells using modified Helmholtz resonators with 2π reflection phase.
• Engineered reflection phase distributions to reshape wavefronts between trapezoidal and triangular forms.
• Verified performance through numerical simulations and experimental testing.

Main Results:

• Achieved broadband performance from 3000 Hz to 4500 Hz, covering a bandwidth of 40.5%.
• Demonstrated the ability to reshape reflected wavefronts and create enlarged illusions.
• Experimental validation confirmed the proposed methodology's effectiveness.

Conclusions:

• The developed broadband conformal acoustic illusion coatings offer significant advancements over existing technologies.
• The methodology enables efficient acoustic wavefront manipulation with potential for diverse applications.
• Subwavelength-thick metacells provide a promising platform for advanced acoustic functionalities.