Non-periodic metasurfaces for blazing and beam splitting

Abstract

Blazing (retro-reflection) of an obliquely incident wave has classically been achieved with periodic blazed gratings, such as the sawtooth grating. In this work, non-periodic metasurfaces are explored to realize similar blazing effects under oblique plane-wave illumination. Genetic Algorithm is used to optimize the surface's local reflection phase over the entire finite aperture, for a particular scattering response (e.g. blazing). Such non-periodic and random surfaces can open doors for the design of blazing surfaces beyond typical periodic gratings and their limitations, e.g. reducing and flattening of side-lobe levels, and other scattered beam characteristics such as beam-splitting. The theoretical method is verified by full-wave electromagnetic simulations at X-band.