Sparse Metasurfaces: From Theory to Practical Implementations
Résumé
Metagratings demonstrate an exceptional efficiency in controlling diffraction patterns. Still, they are essentially periodic structures excited by a plane wave. This induces two main drawbacks. First, periodicity limits metagratings to the control of a discrete set of scattered plane waves, not a continuous one. Second, plane-wave-like illumination assumes that the source is placed in the far-field, significantly reducing feeding efficiency. Here, we elaborate on the analytical model of metagratings and show how numerical calculation of Green's functions can be employed to overcome these drawbacks and design sparse metasurfaces capable of creating arbitrary radiation patterns for arbitrary external excitations.
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