Localizing Targets via Properly-Synthesized Orbital Angular Momentum Vortices

As an alternative to delta and delta-square patterns usually exploited in the receive mode for the localization of targets, we propose herein to use ‘orbital angular momentum’ (OAM) antennas. By so doing, it is possible to effectively generate a single isolated null of the pattern rather than a whole row (and/or column) of zeroes in the spectral plane, so that a better localization can be achieved. General considerations are first given showing that the 1 (or −1) OAM vortex order is the best-suited one for such a goal. Then, a Convex Programming synthesis procedure maximizing the localization performance by relying on OAM vortices is given and tested.