High-efficiency multi-channel focusing and imaging enabled by polarization-frequency multiplexing non-interleaved metasurfaces

In microwave communication systems, focusing and imaging have attracted widespread attention due to their application prospects in the information processing and communication fields. Most existing multi-channel focusing and imaging are implemented by interleaved metasurfaces. However, the disadvantages of their large size and low efficiency limit their practical applications in large-capacity and low-loss integrated systems. To solve these issues, here, we propose a non-interleaved polarization-frequency multiplexing metasurface for high-efficiency multi-channel focusing and imaging. The meta-atoms of the non-interleaved metasurface are composed of a metallic ground plate, two dielectric layers, a larger cross-shaped metal structure, and a smaller cross-shaped metal structure embedded by a circular metal aperture. By altering the size of two cross-shaped structures, the designed meta-atom can obtain the independent complete 2 π phase coverage with high reflection efficiency at two different frequency ranges for two orthogonal linear polarization (LP) incidences, realizing polarization multiplexing and frequency multiplexing. Moreover, two types of metasurfaces based on the above meta-atoms are designed to realize multi-channel focusing and imaging with high efficiency. As a proof, the focusing metasurface is fabricated and measured, and the measured results are well consistent with simulated results. Therefore, the proposed scheme has the advantages of high efficiency, multi-channel, and compact size, which possesses broad application prospects in low-loss and multi-channel communication integrated systems.