Current-Only Inverse Design of Anomalous Reflection Metasurfaces

We discuss the automated design (inverse design) of metasurfaces to achieve anomalous reflection and minimize radiation into the specular direction - a condition often referred to as 'perfect anomalous reflection'. We effect the design with a current-only method, in which the object of the optimization is the current (density), as opposed to the surface impedance; the latter is obtained from the current in a post-processing step. The method obtains a significant reduction of radiation in unwanted directions, confirmed by simulation with an external (CST) tool of the entire structure. This communication also adds to the ongoing discussion on locality vs. non-locality to achieve the desired pattern.