Transmitting-absorbing material based on resistive metasurface

A sound absorbing metasurface with coupled resonators

An impedance matched surface is able, in principle, to totally absorb the incident sound and yield no reflection, and this is desired in many acoustic applications. Here we demonstrate a design of impedance matched sound absorbing surface with a simple construction. By coupling different resonators and generating a hybrid resonance mode, we designed and fabricated a metasurface that is impedanc...

Analysis of Multi-transmitting Formula for Absorbing Boundary Conditions

In this paper, we analyze the multi-transmitting formula (MTF) proposed by Liao et al [19]. From the computed reflection coefficients for the fully discrete MTF boundary conditions, we suggest choices for the artificial wave propagation speed, which are different from Liao’s original choice. Theoretical and numerical studies for various incidence angles demonstrate that the suggested choices ef...

Dynamic metasurface lens based on MEMS technology

Helmholtz resonator lined with absorbing material.

A closed-form, two-dimensional analytical solution is developed to investigate the acoustic performance of a concentric circular Helmholtz resonator lined with fibrous material. The effect of density and the thickness of the fibrous material in the cavity is examined on the resonance frequency and the transmission loss. With the expressions for the eigenvalue and eigenfunction in the cavity, th...

Modelling of Absorbing Material Containing Magnetic Platelets

An analytical model for a composite material containing magnetic platelets is presented based on the modified asymmetric Bruggeman’s effective medium theory for permeability. The model takes into account crushing of bulk magnetic material and form factors of inclusions.