Here is the abstract you requested from the dpc_2019 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Compact Air Permeable Acoustic Metamaterial for Low-frequency Band Attenuation|
|Keywords: Acoustic attenuation, Wide band in low-frequency, Air-permeable package|
|Acoustic noise can seriously degrade the performance and reliability of electronic equipment. Conventional acoustic materials general are bulky in size and heavy mass to attenuate acoustic noise, which is generally not suitable for electronic packaging. Accordingly, a physically compact, wideband acoustic attenuator is the goal of this research. Currently, there are two main approaches to achieve sound attenuation with both negative effective density and modulus: intrinsic and inertial acoustic metamaterials. Usually, intrinsic acoustic metamaterials are made of soft substances (e.g., rubber) to significantly decrease the phase speed of sound. Inertial acoustic metamaterials utilize local resonances to counteract the sound energy (e.g., a Helmholtz resonator, a rubber sheet with added masses, or a large tube with side holes). Nevertheless, those designs are not generally suitable for low-frequency applications in compact sizes, and some of them lack the ability to withstand air pressure variation, which is induced by accumulated heat and is a common problem for electronic devices. Active approaches require sophisticated designs and sizeable peripheral equipment for support. Therefore, a novel design of a passive acoustic metamaterial for attenuation in the low-frequency range, which is compact and compatible to heat and air pressure variation, motivates the path of this research. In this study, an air permeable labyrinth element acoustic metamaterial for sound isolation in a wide, low-frequency band is studied. This open-air-path design at a deep sub-wavelength scale promises high sound absorption from thermoviscous effects and ensures air permeability. An analytical model was developed to evaluate candidate design approaches, with experimental testing to validate the model and demonstrate the selected concept designs. Experimental results exhibit an almost unity absorption over a large range of low frequencies. The effectiveness and repeatability of acoustic attenuation was evaluated using a variety of structural configurations, which demonstrated good tunability in the characteristics of interest.|