  Active development is taking place in reconfigurable and static metasurfaces
that control and optimize reflections. However, existing designs typically only
optimize reflections from the metasurface panels, neglecting interference with
reflections originating from supporting walls and nearby objects in realistic
scenarios. Moreover, when the area illuminated by the transmitting antenna is
larger than the metasurface panel, the total scattering pattern deviates
significantly from the metasurface panel's reflection pattern. In this study,
we investigate how engineering the metasurface properties can modify the total
scattering pattern, enabling the modification and optimization of reflections
from significantly larger illuminated areas than the metasurface panel. To
accomplish this, a general design approach is developed to create periodical
metasurfaces with controlled reflection phase and amplitude for arbitrary
Floquet channels. By combining these reflections with those from the
surrounding walls, the total scattering can be manipulated to produce desired
scattering properties. The study demonstrates how appropriately designed
metasurfaces can modify reflections from surrounding walls, enhancing the
functionalities of metasurfaces. These findings are intended to facilitate
advancements in engineering and optimizing wave propagation channels,
particularly for millimeter-wave communications.
