Font Size: 

A quasi two-dimensional acoustic metamaterial with negative bulk modulus is proposed, fabricated and experimentally characterized. The structure consists of a two dimensional array of cylindrical boreholes opened to a waveguide. Experiments are performed using a slab of seven layers and the effective parameters are extracted from the measured transmission and reflection spectra. The skin depth is the region with negative modulus is also determined as a function of frequency. The data are well supported by a semi-analytical model based on multiple scattering and by finite elements simulations.

acoustic metamaterial, negative bulk modulus