Metagratings for Perfect Anomalous Refraction

We formulate a design procedure for metagratings (MGs), periodic structures composed of only a handful of polarizable particles (meta-atoms) per period, for perfect anomalous refraction. The MGs are comprised of three layers of metallic strips loaded by printed capacitors, whose individual geometry and respective positions can be tied to the scattered fields in an analytical manner. Utilizing the analytical model, we derive conditions on the multilayered configuration and the capacitive loads that would yield perfect coupling of an incident wave towards a desirable refraction angle, while suppressing coupling to all other propagating spurious Floquet-Bloch modes. The simultaneous semianalytical resolution of multiple degrees of freedom, verified via full-wave simulations, demonstrates the potential of MGs as a platform for extreme wave manipulation, greatly reducing the computational effort typically required to obtain physical realizations of comparable metasurfaces.