Holographic Communication Using Intelligent Surfaces

Holographic communication is intended as a holistic way to manipulate, with unprecedented flexibility, the electromagnetic field generated or sensed by an antenna. This is of particular interest when using large antennas at high frequency (e.g., at millimeter-wave or terahertz), whose operating condition may easily fall in the Fresnel region (radiating near-field), where the classical plane wave propagation assumption is no longer valid. This article analyzes the optimal communication involving large intelligent surfaces realized, for example, with metamaterials as possible enabling technology for holographic communication. It is shown that traditional propagation models must be revised and that, when exploiting spherical wave propagation in the near-field region, new opportunities are opened, for example, in terms of feasible orthogonal communication channels.