Fig. 2: Design and simulation verification of a generalized impedance metasurface.
a Illustration of the definition of the generalized impedance metasurface. Two pressure fields, \({p}^{A}\left(x,y,z\right)\) and \({p}^{B}\left(x,y,z\right)\), are placed in the space regions A and B. A regular lattice with a particular internal structure is positioned between them. Each cell in the lattice is rigidly isolated. The connection between the sound fields and the lattice is supposed to achieve 100% transmittance to reduce the design complexity. A plane wave with an incident angle θin is split into two plane waves with transmission angles θt1 and θt2 after passing through the metasurface. b Schematic diagram of the generalized impedance unit. c Analytical determination of the required impedance matrix described by the pseudo-real expression: R11 (gray curve), X11 (orange curve), X12 (green curve), X22 (blue curve). The target impedance components (circular points) and impedance components of the practical structure are obtained through optimization (square points). d, e Verification of beam splitting based on generalized impedance theory described with d the three-layer numerical model and e the practical structure. f Mode analysis of the transmitted field for the three-layer numerical model (blue line) and the practical structure (green line).
