Programmable Metasurface for DOA Estimation from Mobile Objects and Wave Redirection

A method to estimate the direction of an incoming wave and to redirect it to a desired direction is proposed. The tasks are achieved by a metasurface exploited as reconfigurable intelligent surface (RIS). To estimate the direction-of-arrival (DOA), the RIS is configured as tunable parabolic reflector, making the incident waves converge to a common focal point where a receiving antenna is placed to act as a power detector. To redirect the waves, the RIS is configured as a phase-gradient reflector. Experimental measurements performed on a programmable metasurface in an anechoic chamber allow validating the proposed method.