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Broadband compact circularly polarized antenna based on one novel cross‐layer polarization‐dependent metasurface structure

In this letter, a novel broadband compact circularly polarized antenna is proposed, which consists of a novel 4 × 4 cross‐layer metasurface (MS) structure and a slanted slot fed through microstrip line. The cross‐layer MS structure is formed by loading several cross‐layer stacked patches along one dimension of traditional square MS structure, and these stacked patches are located below the gaps of the original square patches directly. Compared with traditional square MS structure, the proposed cross‐layer MS structure can be viewed as one polarization‐dependent MS, exhibiting different reflection features in two orthogonal dimensions. Then, by properly tailoring the phase difference of the polarization‐dependent MS structure between the two orthogonal dimensions and combining it with a slanted coupling slot, two degenerate modes can be generated and then a wideband circular polarization radiation can be realized. Furthermore, the proposed antenna has a much compact aperture size of 0.41λ0 × 0.41λ0 due to the cross‐layer stacked patches, which can also enlarge the total capacitance by introducing extra cross‐layer capacitances. Finally, measured results show that the −10 dB impedance bandwidth of the proposed antenna is 39.6% (5.82 ~ 8.69 GHz), and 3‐dB axial ratio bandwidth is 26.3% (6.51 ~ 8.48 GHz) with a peak gain of 5.81 dBi. The simulated and measured results are in good agreement to verify the good performance of the proposed antenna.