Fig. 5: Measurements of the near-field PDCM-based holographic MIMO.

a Photograph of the dual-channel holographic MIMO system based on the 2-bit PDCM and EIT. Details about the metasurface and probe array are provided in the inserted figure. b Photograph of the receiver blocked by a cardboard in measurements. c, d The measured constellation diagrams of Channels 1 and 2, respectively. The blue and red dots represent the systems working in free space and with the cardboard blocking, respectively.