Binary Huygens' metasurface: A simple and efficient retroreflector at near-grazing angles

In this work we report the design and simulation of a metasurface retroreflector for near-grazing incidence. The retroreflector is a Huygens' metasurface that is coarsely discretized to just two cells per grating period. The coarse discretization leads to a relatively large element size, which in turn enables one to realize the metasurface unit cells using a simple, single-layered metasurface structure of a dipole backed by a ground plane. A full-wave Floquet simulation of the metasurface demonstrates retroreflection at 94% power efficiency for an incident TE plane wave at 82.87°. A simulation of the finite-length metasurface also shows efficient retroreflection in the far-field.