Strong attenuation using subwavelength apertures in a phononic plate

International audienceThe aim of this study is to demonstrate an acoustic screening in a periodically perforated plate. The phononic structure is constituted of sub-wavelength slit arrays, of the order of λ/10, in an aluminium plate that is immersed in water. These arrays act as Fabry-Pérot acoustic resonators, and through the coupling effect between them, we obtain a series of asymmetric shape peaks in the transmission spectra. This leads to an enhanced transmission at the res-onance frequencies as well as to improve the attenuation significantly at the anti-resonance frequencies. Therefore, the composition between these anti-resonance frequencies, through the geometrical features, enables to reach an attenuation up to 23 dB, with a relative band-width of 11% and a center frequency of 175 kHz