The use of specular reflecting passive electromagnetic skins (EMSs) in NLOS wireless backhauling at carrier frequencies ranging from sub-6GHz to W-band is dealt with. A set of design guidelines is derived to predict the relation between the meta-atom layout and the NLOS link efficiency as well as the scalability of the EMS-based backhauling to different carrier/link-distances. The results of several numerical experiments are reported and the total path attenuation (TPA) is evaluated by varying the EMS layout, the EMS material, the range of the wireless link, and the incidence angle from the transmitter in comparison with that from traditional flat conducting screens (PCSs), as well. The reliability and the effectiveness of the proposed EMS-based solution for NLOS wireless links are validated through both full-wave numerical simulations and experimental measurements on an EMS prototype in a realistic environment.