Development of Broadband Ultra Micro-Perforated Panels Based on MEMS Technology

Abstract

Fabrication process of ultra micro-perforated panels (ultra-MPPs) with perforations of diameter below 100 um based on MEMS technology is expatiated in this paper. As a promising alternative to the conventional porous absorbing materials, MPP absorber is now being widely used in noise control engineering. Theory reveals that the maximum sound absorption bandwidth of a single MPP absorber could be achieved by reducing the perforation diameter to a certain limit and the desirable perforation diameters are less than 100um under many circumstances. However, due to the limitation of traditional manufacturing tools and techniques, MPPs with ultra-micro perforations of diameter less than 100um, namely for ultra micro-perforated panel (ultra-MPPs), have seldom been investigated yet. In this study, micro electro mechanical systems (MEMS) technology was applied to a trial production of ultra-MPPs and the measurement of their normal absorption coefficients were carried out in the impedance tube. Results show that ultra-MPPs could attain high absorption over a broad frequency range, indicating that as a micro machining process, MEMS technology is suitable for fabricating ultra-MPPs in order to ensure the absorption performance.