Binary Huygens' Metasurfaces: Experimental Demonstration of Simple and Efficient Near-Grazing Retroreflectors for TE and TM Polarizations

This paper investigates the retroreflective properties of a type of periodic metasurface, which is aggressively discretized to include only two cells per grating period. The resultant metasurface, which we term the binary Huygens' metasurface, dramatically simplifies the design toward highly efficient, low cost, and robust metasurface retroreflectors. Using this discretization method, we designed, simulated, and measured two binary Huygens' metasurfaces that retroreflect an incident plane wave at 82.87 degrees from broadside, for TE and TM polarized waves, respectively. The simulated results for a 2-D infinite structure show power efficiencies of 94% (TE) and 99% (TM). The measured results show a power efficiency of 93% for both TE and TM polarizations. This shows that it is possible to obtain a high retroreflection power efficiency at an angle of choice using a very simple (slot or patch) metasurface design. The proposed design methodology allows one to achieve not only retroreflection but also reflection to arbitrary angles, with very high efficiency, which diversifies its uses.