Ultrathin Coding Metasurface for Underwater Wave Focusing, Branching and Self-Bending Generation with One Single Actuator

A novel metasurface is proposed that aims to generate underwater acoustic waves with various functions by only one actuator. Each unit consists of an air cavity sandwiched on side a vibration plate and connecting rubber supports. By properly selecting the ratio  unit lengths, phase shift π can be attained constitute binary coding metasurface. Three demonstrations, including focusing, branching self-bending waves, are chosen validate functionality design. The design also shown work over wide frequency range through changing ratio. In addition, extremely compact, thickness about 1/100 target wavelength. Compared commonly used phased array transducers utilized this offers has advantage needing single actuator as opposed lumped electrical control system.