Multi-Input Multi-Output Beamforming with Single Layer Impedance Metasurfaces

Metasurfaces can shape electromagnetic wavefronts at will with electromagnetically thin structures. In this paper, we discuss metasurfaces, consisting of an impedance layer above a grounded substrate, that handle multiple inputs simultaneously. When combined with embedded sources, such surfaces can radiate highly-directive beams at prescribed directions. On the other hand, when illuminated by incident plane waves, they can manipulate the direction and far-field pattern of the reflected radiation. Both scenarios are examined for a dual-input operation with the aim of producing highly-directive beams for both inputs. Full-wave simulations, where the metasurface is implemented with realistic copper traces, are performed to verify the desired dual-input operation.