Dual-Band Resonant Acoustic Metasurfaces from Nested Negative Effective Parameter Unit

Area of Science:

• Acoustic Metasurfaces
• Wave Physics
• Materials Science

Background:

• Phase gradient acoustic metasurfaces show structural dependence in imaging.
• Performance varies due to differences in negative effective parameters of resonant unit cells.
• The link between imaging performance and negative effective parameters near resonance, especially in multi-band structures, is understudied.

Purpose of the Study:

• To investigate the influence of negative effective mass density and modulus on acoustic metasurface imaging quality.
• To compare single-band and dual-band nested metasurfaces in series and parallel configurations.
• To establish a comparative model using effective parameter theory and local resonance characteristics.

Main Methods:

• Developed a comparative model combining effective parameter theory and local resonance.
• Analyzed single-band and dual-band nested metasurfaces in series and parallel arrangements.
• Investigated the correlation between negative effective parameters and imaging performance.

Main Results:

• Single-band structures show positive correlation between imaging performance and absolute value of negative effective parameters.
• Dual-band configurations demonstrate more stable imaging with smaller inter-band differences in negative parameters.
• Series-type nested structures outperform parallel-type in reflection imaging, despite slightly less design flexibility.

Conclusions:

• Negative parameters fundamentally govern acoustic metasurface imaging.
• This research provides theoretical guidance for designing high-performance multi-band acoustic devices.
• Understanding parameter-band differences is crucial for stable dual-band acoustic imaging.