Dual-band transmission polarization conversion metasurface and its reconfigurable-phase design

Although abundant transmission polarization conversion metasurfaces (T-PCMs) have been reported, a dual-band T-PCM has only received little attention. Moreover, a reconfigurable-phase design of the T-PCMs is limited to a single-frequency band operation. There is hardly any literature to integrate dual-band and reconfigurable-phase features into a T-PCM. Herein, a dual-band T-PCM is presented based on the Fabry-Pérot-like resonant cavity. Particularly, the T-PCM meta-atom contains dual anisotropic patches distributed in different layers, and the novel dual-patch structure introduces multiple current modes to implement dual-band operation. Further, a reconfigurable-phase design of the dual-band meta-atom is performed, and four PIN diodes are embedded in each meta-atom to realize a 1-bit reconfigurable phase. In this way, the T-PCM meta-atom can simultaneously achieve high-efficiency 90° polarization rotation and 1-bit dynamic phase manipulation in 2.3–3.0 GHz and 4.4–7.5 GHz. By changing the encoding of the T-PCM, both cross-polarized transmission and beam manipulation are demonstrated in two divided bands. A sample is fabricated and measured to validate our design, and the results confirm the simulations. With the advantages of ingenious design and a clear operation mechanism, the novel dual-patch structure can be extended to the terahertz and optics regimes.