Wave scattering by metasurfaces using the fast hybrid method

In this paper, we develop the fast hybrid method (FHM) for full wave simulations of metasurfaces. In the FHM, computational efficiency is achieved by formulating electromagnetic fields using the Foldy-Lax multiple scattering equation, with re-useable T matrices in the library, and computing the solutions with the FFT operations. In this work, both Vector Cylindrical Wave (VCW) and Vector Spherical Waves (VSW) are used for T-matrices and Foldy-Lax multiple scattering equations. The full-wave simulations are illustrated with two examples: (i) a metasurface optical focusing lens and (ii) a metasurface optical absorber. For the case of 1,296 unit cells, the FHM requires merely 70 seconds and 120 MB on a standard desktop, which is 442 times faster and 0.25% memory usage when compared with the FEKO commercial software.