Multi-frequency compact encoding metasurface for independent beam control

Abstract Encoding metasurfaces, serving as innovative materials that facilitate the integration of the physical and digital realms, offer engineers a more streamlined and effective approach to manipulating electromagnetic beams. To optimize the functionality of metasurfaces, it is imperative to attain multi-frequency beam control on a single metasurface. In this paper, we present the implementation of a reflective encoding metasurface capable of independently modulating the phase of high-frequency and low-frequency electromagnetic waves at two disparate frequencies through the manipulation of octagonal copper rings and copper patches on the unit cells. To enhance and achieve more precise beam control accuracy, a genetic algorithm was utilized to optimize the arrangement of low-frequency and high-frequency units individually, which were subsequently integrated to facilitate beam deflection at both frequencies. Simulation results indicate that the proposed compact dual-frequency encoding metasurface effectively manipulates incident electromagnetic waves at 6 GHz and 19 GHz, achieving beam deflection within 45° in the half-space. Experimental testing was performed in a microwave anechoic chamber to verify the simulations, and the experimental results are consistent with the simulations. The proposed metasurface has potential applications in compact space and multi-channel communication services due to its good beam control capability.