Low‐profile circularly polarized metasurface antenna with tailored reflection phase

Abstract

A low‐profile metasurface antenna with circularly polarized radiation and tailored anisotropic reflection is proposed in this letter. The metasurface antenna composed of excitation structure (microstrip line with coupling slot) and a metasurface layer. The metasurface functions for two goals, generating circularly polarized wave for radiation and tailoring reflection phase for scattering, respectively. The overall structure of the metasurface antenna is compact with a dimension of 0.67λ × 0.67λ × 0.05λ at 5 GHz. Numerical and measured results confirm that the metasurface antenna exhibits 11.1% −10 dB S₁₁ bandwidth from 4.68 to 5.23 GHz, 10.8% 3 dB axial ratio bandwidth from 4.782 to 5.37 GHz and a maximum gain of 6.83 dBic. Besides, the metasurface antenna achieves anti‐phase reflection under orthogonal polarized incident waves at around 5 GHz. To demonstrate a potential application, 16 identical metasurface antennas are put in a 4 × 4 array. The metasurface antenna array achieves directive circularly polarized radiation with a maximum gain of 15 dBic. On the other hand, when under normal illumination, the scattering field of metasurface antenna array is redistributed due to phase cancelation, so that the backward radar cross section of the array is significantly reduced, which is applicable for military platform.