Recently, the well-developed sub-wavelength artificial electromagnetic structures, including the metamaterials and metasurfaces, have attracted much attention owning to the significant advantages on arbitrarily manipulating the wavefront of incident electromagnetic waves. Various applications have been found for those nanostructures / nanoantennas, for examples, the flat lenses and axicons, beam-splitters and spectrum-splitter, holograms, all-optical logical operations, polarizers, as well as vector beam generators. This especial session is aim to call for the state-of-the-art research achievements on the topic of sub-wavelength Metamaterials / metasurfaces, and exchange the ideas for the emerging applications in the electromagnetic wave manipulations and antennas.