Direction-of-Arrival (DOA) Estimation based on Spacetime-Modulated Metasurface

We introduce the concept of DOA estimation based on spacetime-modulated 2D-patch-array metasurface. Such a system, compared to conventional DOA estimators, offers the key advantage of requiring only one receiving antenna, with the metasurface placed in front of it. The patch rows of the metasurfaces are time-modulated by different orthogonal codes, so that the metasurface is de facto spacetime-modulated. The DOA is found by measuring the delay between the different waveforms obtained by multiplication of the received mixed-signal with the different codes.