Compact circularly polarized metasurface antenna based on characteristic mode analysis

This article introduces a novel, single‐layer, low‐profile, circularly polarized metasurface antenna. Through characteristic mode analysis, the optimization of a 3×$\times$3 rectangular metasurface structure was performed. Two orthogonal modes were selected as the operating modes, and improvements to the metasurface structure were made to achieve a 90∘$^\circ$ 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 ×$\times$ 40 mm ×$\times$ 3 mm (0.67 λ$\lambda$ ×$\times$ 0.67 λ$\lambda$ ×$\times$ 0.05 λ$\lambda$), featuring a −10 dB impedance bandwidth of 27.8% (4.49–5.94 GHz). The 3 dB axial ratio bandwidth is 14.2% (5.25–6.05 GHz), with a maximum gain of 7.26 dBi. This article introduces a novel, single‐layer, low‐profile, circularly polarized metasurface antenna. Through characteristic mode analysis, the optimization of a 3×$\times$3 rectangular metasurface structure was performed. Two orthogonal modes were selected as the operating modes, and improvements to the metasurface structure were made to achieve a 90∘$^\circ$ 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 ×$\times$ 40 mm ×$\times$ 3 mm, featuring a −10 dB impedance bandwidth of 27.8% (4.49–5.94 GHz). The 3 dB axial ratio bandwidth is 14.2% (5.25–6.05 GHz), with a maximum gain of 7.26 dBi.