An acoustic metasurface with simultaneous phase modulation and energy attenuation

We introduced a rigid structure into the acoustic metasurface design, the proposed labyrinth structure is based on the equivalent medium theory and different media are replaced by curly labyrinth. Layered media theory and equivalent medium theory are combined to design the arbitrary acoustic metasurface structure. An acoustic metasurface studied in this paper realized simultaneous phase modulation and energy attenuation in the air, the effective phase modulation range covered from 30 to 90 and the energy attenuation is over 40%. According to layered media theory which could modulate the acoustic wave direction, the metasurface with same function can also be applied to underwater case. Corresponding simulation results are calculated by FEA. Finally, by introducing the curly labyrinth theory, the underwater acoustic metasurface with simultaneous phase modulation and energy attenuation is designed and verified. This paper has potential applications in rigid underwater acoustic metasurface designs with low frequency, adjustable direction and sound energy attenuation.