Acoustic metasurfaces designed via topology optimization for regional sound insulation

This study proposes a metasurface that effectively obstructs the propagation of incident waves at any angle over broadband frequencies from propagating to a specific area. To this end, we apply a topology optimization method to design an appropriate metasurface structure and optimize their shapes using different input parameters. Sound insulation using metasurfaces is discussed and the underlying mechanism is verified using a simple model-the waveguide mode and cancellation resulting from the phase difference between the sum of the inlet and intermediate paths. Accordingly, we propose metasurfaces with simple geometries and numerically confirm their functions to effectively attenuate sound propagation toward a specific area generated by incident waves at various angles.