Multifunctional polarization converter based on multilayer reconfigurable metasurface

In the modern wireless communication system, the manipulation for polarization of electromagnetic wave plays a important role in improving the capacity and reliability of communication. In this paper, a multifunctional polarization converter (MFPC) based on the multilayer reconfigurable metasurface is proposed, which can assist the source antenna to transmit and receive multiple polarization signals. The MFPC consists of a grating which can filter out the undesired polarization and four layers of metasurfaces incorporated with PIN diodes. The functions of the MFPC include LTC and LTL polarization conversions, co-polarization transmission and reflection for arbitrary polarization. By changing the states of PIN diodes, the functions of MFPC can be dynamically switched. Loaded on the aperture of source antenna, the proposed MFPC can serve as a transmissive array with multiple polarization channels, and can also provide EM protection for source antenna by reflecting the incoming interference waves. Cascading of the metasurfaces produces Fabry-Perot resonance in the MFPC, and it contributes to the realization of LTC and LTL polarization conversions. To verify the performance of the proposed MFPC, the prototype is fabricated and tested. The measured results show that the fractional bandwidths of four functions are all higher than 31.9% with transmission or reflection coefficients higher than −2 dB. The frequency band of each function is mainly concentrated in S-band. The measured data are in agreement with the simulated results.