  HyperSurfaces (HSFs) are devices whose electromagnetic (EM) behavior is
software-driven, i.e., it can be defined programmatically. The key components
of this emerging technology are the metasurfaces, artificial layered materials
whose EM properties depend on their internal subwavelength structuring. HSFs
merge metasurfaces with a network of miniaturized custom electronic
controllers, the nanonetwork, in an integrated scalable hardware platform. The
nanonetwork receives external programmatic commands expressing the desired
end-functionality and appropriately alters the metasurface configuration thus
yielding the respective EM behavior for the HSF. In this work, we will present
all the components of the HSF paradigm, as well as highlight the underlying
challenges and future prospects.
