Fast design of polarization independent metasurfaces for shaping electromagnetic waves

The metasurfaces have recently been demonstrated to provide full control of the phase responses of electromagnetic (EM) wave scattering over subwavelength scales, enabling a wide range of practical applications. Here, a method for fast design of polarization-independent metasurfaces is proposed. A nonlinear fitting scenarios is employed to precisely predict reflective phase response of the metasurface. To obtain the optimal performance, nonlinear fitting scheme and genetic algorithm are combined. Since low-Q-factor resonant able to introduce wideband and smooth phase response, combining with lossless substrate, the metasurface with high reflective amplitude and wideband corresponding phase response can be obtained. As verify, two types metasurface examples characterized of coding metasurface on RCS reduction and reflective focusing lens are demonstrated.