Broadband directional acoustic waveguide with high efficiency

We have realized both theoretically and experimentally a directional acoustic transmission in a bended waveguide. For acoustic plane waves that incident from the two openings of the waveguide, an efficient partial band gap of dispersion relations is yielded by employing a linear two-dimensional phononic crystal properly designed according to the structural parameters of waveguide. As a result, a highly efficient directional transmission of acoustic waves can be achieved within a broad frequency range. The numerical predictions agree well with the experimental results. This should be potentially significant in various areas such as medical ultrasound and duct acoustics.