Lossless Planar Metasurface for Wide-Angle Anomalous Refraction Based on an Efficient Surface Field Optimization

In this work, a numerically efficient surface field optimization is used to design a locally lossless and passive metasurface (MTS) performing anomalous refraction. The MTS consists of the cascade of three patterned metallic layers, modeled through homogenized impedance sheets. A certain number of evanescent Floquet modes are introduced through an optimization procedure aiming at minimizing the real part of the sheets surface impedance. Numerical results show a near-perfect anomalous refraction without reflection for arbitrary incidence and refraction angles.