  This paper introduces a new approach to localize user devices located in
non-line-of-sight (NLOS) areas using a passive, non-reconfigurable, and
frequency-selective metasurface called metaprism. By analyzing the spatial
filtering of subcarriers in the orthogonal frequency division multiplexing
(OFDM) signal transmitted by each user device, the base station can estimate
the device's angle of view, distance, and subsequently its position. Two
different criteria are proposed for designing the frequency response of the
metaprism, depending on whether the users operate in the far-field or
near-field region of the metaprism. Simulation results in the millimeter-wave
band demonstrate that the system can achieve an accuracy of less than 2 degrees
in angle estimation and in the order of decimeters in position estimation.
