Through-Wall Wireless Communication Enabled by a Metalens

Getting wireless signals around obstacles or passing them through walls is proven to be challenging for electromagnetic waves with a short wavelength and some energy-efficient buildings due to thick insulating materials. Here, we propose a scheme of through-wall wireless communication by applying purposely designed passive metalenses for an asymmetric background medium of the wall. An ultrathin metalens consisting of three layers of metallic patterns is applied to focus the incoming waves to the other side of the wall with high efficiency. The focusing effect is verified by scanning the spatial distribution of electric fields. Due to the focusing effect, the wireless signal strength is significantly enhanced while propagating through the wall. To validate its use in the 5-GHz Wi-Fi environment, we demonstrate that the metalens can reconnect a network channel that is otherwise broken due to weak signal strength, and thus, significantly increase the data transmission rate. Our work opens an unobstructive and retrofitting approach for sustaining wireless communication in future eco-friendly buildings beyond 5G and 6G.