  The number of users that can be spatially multiplexed by a wireless access
point depends on the aperture of its antenna array. When the aperture increases
and wavelength shrinks, "new" electromagnetic phenomena can be utilized to
further enhance network capacity. In this chapter, we describe how extremely
large aperture arrays (ELAA) can extend the radiative near-field region to
kilometer distances. We demonstrate how this affects the propagation models in
line-of-sight (LoS) scenarios and enables finite-depth beamforming. In
particular, it becomes possible to simultaneously serve users that are located
in the same direction but at different distances.
