Spherical Large Intelligent Surfaces

As an emerging technology and evolution that goes beyond massive multi-input multi-output (MIMO), large intelligent surface (LIS) has gained much interest. LIS acts as an electromagnetic surface that can transmit, redirect, and receive radiating signals across its entire contiguous surface. It allows for unprecedented energy-focusing, data-transmission and terminal-positioning, and can fulfill the most grand visions for future communication systems. Earlier proposed LISs are in two-dimensional (2D), i.e., planar shapes. In this paper, we extend LISs to be three-dimensional (3D) and deployed as spherical surfaces. Compared to 2D LIS, a spherical LIS has advantages in wide coverage, simple positioning technique, and flexible deployment as reflecting surface.