Micro-silicon phononic crystal with locally resonant theory

The control of acoustic waves on a micro-scale is a critical issue in the development of micro-acoustic devices. In this paper, we demonstrate a locally resonant phononic crystal (PNC) for the control of acoustic waves on a micro-scale. The locally resonant phononic crystal is realized by periodically arranging cylindrical stubs on a silicon plate in a square lattice. Two types of acoustic microwaveguides, i.e., straight waveguide and mirrored “Z” shape waveguide, are designed based on the micro-phononic crystal. Numerical simulation shows that acoustic waves with frequencies in the bandgap range are compelled to propagate along the waveguides. Experimental results also confirm that the locally resonant PNC could effectively control the propagation of acoustic waves with frequencies in the bandgap range. The locally resonant phononic crystal in this paper is believed to be an ideal metamaterial for the acoustic wave control on a micro-scale.