Using MetaPrisms for Performance Improvement in Wireless Communications

In this paper, we put forth the idea of metaprism, a passive and non-reconfigurable metasurface acting as a metamirror with frequency-dependent reflecting properties within the bandwidth of the signal. We show that, with an appropriate design of the metaprism, it is possible to control that each data stream in an orthogonal frequency division multiplexing (OFDM) system is reflected in the desired direction by properly assigning subcarriers to users without the need of control channels and dedicated channel state information (CSI) estimation schemes. Furthermore, the metaprism can also be designed so that it focuses the signal towards a specific position depending on the subcarrier, provided that the user is in the near-field region of the metaprism, with consequent path-loss reduction. A critical discussion is also presented about the path-loss reduction obtainable from metaprisms and, more generally, from metasurfaces. The numerical results show that this solution is effective in extending the coverage in areas experiencing severe non line-of-sight (NLOS) channel conditions, thus making it an interesting alternative to reconfigurable metasurfaces when low-cost, no energy consumption, and backward compatibility with existing wireless standards are required.