Design of broadband transmission polarization conversion metasurface based on cross-shaped resonators

In this paper, it is proposed to combine multiple plasmon resonances and Fabry–Perot-like resonance to realize broadband transmission polarization conversion metasurface (TPCM). The broadband TPCM was designed using cross-shaped resonators and two metal gratings. It is shown that the multiple plasmon resonances can greatly expand the polarization conversion bandwidth, and the Fabry–Perot-like resonance can greatly improve its efficiency, the efficient broadband TPCM is realized through their combination. The broadband TPCM of different frequency bands can be obtained by changing the structure parameters. A set of parameters were selected for simulation and experiment to verify the design. The simulation results show that the TPCM can convert linearly polarized waves into its cross-polarized waves with 2 dB bandwidth of 8.1–26.8 GHz and the PCR is greater than 98%. As the oblique incident angle is up to 45°, the cross-polarization transmission is still greater than − 2 dB in the frequency range of 17.0–26.4 GHz, greater than − 3 dB in the frequency range of 8.0–15.8 GHz, and the PCR is more than 97%. The experimental results are in good agreement with the simulation results.