Programmable Coding Metasurface for Dual-Band Independent Real-Time Beam Control

Active metasurfaces pave a way for manipulating electromagnetic (EM) waves in real-time by incorporating with tunable materials or components, emerging as an attractive solution to achieve versatile EM functionalities in dynamic fashions. However, most of the active metasurfaces demonstrated so far only support tunable responses for a certain single frequency band, or have obvious frequency cross-talks that cannot provide dual-band independent operations, limiting their further uses in practical applications. Here, we propose a 1-bit high-efficiency programmable metasurface to achieve completely independent functions with real-time reconfigurability controlled by FPGA hardware system in both C-band and X-band. Specifically, the metasurface is designed with abilities of generating multi-beams or twin-beam scanning in the low frequency band while dynamic beam-scanning in high frequency band. As the experimental verifications, a double-layered metasurface has been fabricated and tested, and the measured results agree well with the simulations, demonstrating its abilities of independent, high-efficiency, real-time, and programmable manipulation of EM waves in two discrete frequency bands. The proposed concept may largely enhance the information capacity of the metasurface, bringing new degrees of freedom in achieving versatile tunable functionalities and offering useful applications in the radar and wireless communication systems.