No abstract

We propose a tunable metasurface unit based on a composite sheet of polyvinylidene fluoride (PVDF) membrane and polyimide tape. The deformation of the sheet can be adjusted by applying a voltage to the PVDF membrane, and the phase of reflected acoustic waves can be continuously tuned and spans the full 2π range. Various acoustic functions can be achieved by applying different voltages on the units. The experiment is also given to prove the unit’s ability to control acoustic waves. Our design shows the possibility of dynamically manipulating acoustic waves and designing integrated acoustic devices by piezo-membrane micromechanical system.

In this work, we analytically and experimentally present a perfect and broadband acoustic insulation waveguide composed of gradient impedance boundaries. With these designed impedance boundaries, the incident plane wave will be converted into the surface wave mode and be absorbed or reflected back. The transmission rate reaches nearly zero in a broadband (1800–7000 Hz, typically), and the bandwidth is adjustable to fit different noise spectra. Our results may contribute more possible designs for noise reduction challenges in the waveguide.