Design of wideband circularly polarized metasurface antenna using characteristic mode analysis

Abstract

Abstract A wideband circularly polarized metasurface antenna using characteristic mode analysis is presented in this letter, which is composed of two‐layer substrate, 4 × 4 circular patch metasurface, L‐slot, transmission line, and air spacing. Through mode analysis, the metasurface structure can significantly enhance the bandwidth and gain of the antenna, and realize circular polarization (CP). After excitation, the air spacing and the L‐slot can realize 90° difference between the characteristic angles of the two modes of the metasurface, and finally radiate CP. The measurement results show that the prototype has a −10 dB impedance bandwidth from 5.6 to 8.2 GHz (37.7%), a 3‐dB axial ratio bandwidth from 6.2 to 7.8 GHz (22.9%), and a peak gain of 8.7 dBi at 6.4 GHz.