Fig. 1
Conceptual illustration of a space-time-coding digital metasurface. The reflection coefficient of the metasurface elements is dynamically controlled with discrete phase or amplitude states by applying control voltages to PIN diodes. In the illustrated example, the reflection phase of each coding element is periodically switched according to the digital “0/1” space-time-coding matrix, which can result in an equivalent multi-bit space-coding, such as “0′”, “1′”, “2′” and “3′” (equivalent 2-bit case). This coding strategy enables precise control of EM waves in both space and frequency domains
