Experimental demonstration of directional acoustic radiation based on two-dimensional phononic crystal band edge states

The authors have experimentally studied the radiation of a point acoustic source placed inside a two-dimensional phononic crystal of square lattice. They show that a highly directional radiation with a half-power angular width of 6° can be achieved when operating at the band edge frequency for the phononic crystal. Such combination of a point source and a phononic crystal may serve as highly directional acoustic source in applications.