Self-collimated waves in a waveguide comprised of phononic crystals

Elastic waves in a phononic crystal (PnC) can show various velocities in different directions. In this paper, a waveguide that allows self-collimation of longitudinal waves was designed based on the anisotropic propagation property. Then beam-steering appears in the inlet and outlet of the PnC-based waveguide, which allows controlling the direction of a wave beam through the waveguide. The work included design, fabrication of specimens, and experiments. This study is valuable for nondestructive tests in industry and medical applications.