Coupling surface waves from an oblique incident wave based on a metasurface

In this work, we achieve a method for the complete conversion of incident oblique waves into surface waves. By controlling the amplitudes of the coupled surface waves, both the direction and power distribution of the surface waves on the metasurface can be flexibly designed. First, using TE-polarized Gaussian waves incident at +40° and -40° as design examples, we demonstrate precise control over the direction and power of the coupled surface waves, thereby validating the proposed method for designing surface wave coupling metasurfaces under oblique incidence. Second, by using TE-polarized Gaussian waves incident at 0°, +20°, and +50°, we further demonstrate the capability of the metasurface to couple surface waves across a broad range of incidence angles. Finally, the impedance profile of the metasurface is implemented using subwavelength unit cells, and a physical prototype of the surface wave coupling metasurface is fabricated. Both numerical simulations and experimental measurements confirm the effectiveness of the design approach in simultaneously controlling the direction and power of coupled surface waves under oblique incidence.