Frequency-multiplexed multifunctional coding metasurface based on transmission and reflection modes

In this work, a frequency-multiplexed multifunctional coding metasurface is proposed, which can realize focusing lens at the lower frequency and multiple scattering beams at the higher frequency. The two functions can be manipulated independently. The proposed metasurface is composed of the top metal patch with a circular ring, two fan rings and two rectangle patches (CFRP), the bottom metal patch with C-shaped and rectangular metal slots (CRS) and a dielectric substrate. By changing the opening direction and size of CRS and the tilt direction and fan ring size of CFRP, the amplitude and phase of transmission and reflection can be modulated, respectively. The transmission mode works at 7 GHz, which can form focal points in different focal planes. The reflection mode works at 17.5 GHz, which can form multiple scattered beams in different directions in the far field. To further verify its practical feasibility, the proposed metasurface is fabricated and measured, the experimental results are in good agreement with the numerical simulation results. The proposed metasurface provides new possibilities to develop multifunctional devices.