This paper introduces a novel, single-layer, low-proffle, circularly polarized metasurface antenna. Through characteristic mode analysis, the optimization of a 3×3 rectangular metasurface structure was performed. Two orthogonal modes were selected as the operating modes, and improvements to the metasurface structure were made to achieve a 90° phase difference between these modes. The adoption of a coplanar waveguide structure enables the excitation of the metasurface, facilitating circularly polarized radiation performance for the two selected modes. The antenna’s dimensions are 40 mm × 40 mm × 3 mm (0.67 λ × 0.67 λ × 0.05 λ ), featuring a -10 dB impedance bandwidth of 27.8% (4.49 GHz - 5.94 GHz). The 3 dB axial ratio bandwidth is 14.2% (5.25 GHz - 6.05 GHz), with a maximum gain of 7.26 dBi.