Study of ultra-wideband acoustic metamaterial based on multi-order broadband resonance band coupling of ultra-micro perforated panel

Ultra-micro perforated panels (UMPPs) have demonstrated exceptional potential for suppressing attenuation in higher-order resonance bands, enabling the design of structurally simple yet highly efficient acoustic absorbers. This study advances the field by introducing series- and parallel-coupled UMPP systems to achieve ultra-wideband sound absorption through the coupling of multi-order resonance bands. The acoustic impedance models for these configurations are developed, along with a detailed framework for calculating sound absorption coefficients. Theoretical investigations explore double- and triple-layer series UMPP structures as well as two- and three-unit parallel UMPP systems, each engineered to broaden the absorption bandwidth through resonance band integration. The influence of key structural parameters, such as cavity depth and perforation dimensions, on absorption performance is systematically analyzed. Experimental validation, conducted using impedance tube measurements for UMPPs with sub-0.1 mm perforations, confirms the accuracy of the theoretical predictions. Results reveal that multi-order wideband resonance coupling in UMPPs with minimal attenuation effects significantly enhances sound absorption bandwidth, offering a robust pathway for practical applications of ultra-wideband acoustic metamaterials in noise control. This study highlights the versatility of UMPP systems in achieving both low-frequency and broadband sound absorption, providing remarkable design flexibility while maintaining structural simplicity.