Design of a new metasurface and its application for linear to circular polarisation conversion

摘要

A new type of metasurface (MTS) structure consisting of two diagonally connected rings is proposed. Proposed MTS with 16-unit cells are arranged in 4 x 4 cells, which converts linearly polarised (LP) to circularly polarised (CP) wave with axial ratio bandwidth (ARBW) of 50 MHz. Four different LP antennas, microstrip fed, coaxial fed, slot antenna, and aperture antenna have been used to test the utility of the MTS for conversion LP to CP. LP to CP has been achieved by merely placing MTS as a superstrate above these antennas. Microstrip antenna has impedance matching bandwidth (IMBW)170 MHz (2.51-2.68 GHz) while ARBW is 20 MHz(2.52-2.56 GHz). The coax fed has IMBW 100 MHz (2.5-2.6 GHz), and ARBW is 50 MHz(2.53-2.58 GHz). Slot antenna has IMBW 830 MHz(2.16-2.99 GHz); however, ARBW is 80 MHz (2.40-2.48 GHz). Aperture antenna has IMBW 710 MHz(2.16-2.87 GHz), and ARBW is 80 MHz(2.56-2.64 GHz). Coaxial fed and aperture antenna have fabricated with the MTS, and their measured results agreed well with simulated, which validate the effectiveness of the proposed metasurface. The proposed MTS could be useful as a polarisation converter in S-band for any antenna.