Extraordinary acoustic transmission at low frequency by a tunable acoustic impedance metasurface based on coupled Mie resonators

The effective impedance modulation of artificial acoustic metamaterials is crucial in application scenarios. Here, a Mie-resonator dimer is proposed as a tunable mutual inductive coupled unit to drive a mismatched to matched impedance transition, which can achieve a wide impedance modulation range. We have demonstrated a widely tunable impedance modulation to realize an extraordinary acoustic transmission at low frequency by using the metasurface with a Mie-resonator dimer. Based on full-wave simulations, a two-port equivalent circuit model is made to explain the mechanism of the impedance modulation. Moreover, the proposal metasurface can be tuned to exhibit any desired transmittance.