Broadband tunable acoustic metasurface based on piezoelectric composite structure with two resonant modes

Abstract In this letter, we propose a deep-wavelength tunable acoustic metasurface composed of a fixed piezoelectric composite structure with a broad operating frequency range. The metasurface unit has two tunable resonant frequencies determined by specific external inductors and can continuously modulate the phase of the transmitted wave. The influence of the inductors on resonant frequencies are studied by simulation and experiment. Moreover, the functions of acoustic beam steering and focusing by the designed metasurface at three arbitrarily chosen frequencies are verified in simulation. This work may have good potential in the design of acoustic metasurfaces with broadband operating frequencies.