Amplitude‐Phase Independently Encoding Space‐Division Multiplexed Wireless Communication Using Beamforming Reconfigurable Metasurfaces

Abstract Wireless communications utilizing reconfigurable metasurfaces have garnered significant attention due to their capability to transmit information without traditional radio‐frequency chains. Space‐division multiplexing techniques, in particular, can be utilized to improve their channel capacity. However, most of them are only implemented through either amplitude or phase encoding. Here, a space‐division multiplexed wireless communication system with amplitude‐phase independent encoding is proposed. By designing dual beams with varying power intensity ratios, dual channels that allow for independent amplitude modulation are established. The phase between the two channels can be independently modulated based on the pattern synthesis algorithm. By using the pattern nulling technique, independent modulation between amplitude and phase can be achieved in each channel. Compared to amplitude‐only modulation, amplitude‐phase modulation offers an additional degree of freedom for carrier wave modulation, which not only increases system capacity but also enhances physical layer security through directional modulation (DM) techniques. To demonstrate this approach, sixteen scattering beams are generated using a beamforming reconfigurable metasurface, and a dual‐channel 4 amplitude phase‐shift keying (4APSK) wireless communication system is experimentally realized. This work paves the way for establishing multiple channels, potentially applicable in multi‐user wireless communications.