Transmission enhancement of acoustic waves through a thin hard plate embedded with elastic inclusions

Abstract

We study the transmission response of acoustic waves through a water-immersed thin hard plate embedded with elastic inclusions. The transmission spectra show a striking peak at the subwavelength region, whose position is almost irrelevant with the incident angle. Our study states that the transmission enhancement stems from the resonant excitation of the localized bending mode in the inclusion. Different from the well-known Fabry-Perot effect, here the resonant frequency reduces rapidly as the sample is thinned down. The theory is further validated by experiment. Potential applications of the abnormal transmission effect produced by such thin plate structures can be anticipated.