Low-Profile Ultrawideband Circularly Polarized Metasurface Antenna Array

Abstract

A compact low-profile ultrawideband circularly polarized (CP) metasurface antenna (MSA) array is presented in this letter. The array consists of 2 × 2 sequentially rotated symmetric MSA elements and a wideband four-way feeding network providing stable phases of 0°, 90°, 180°, and 270°. By using the constructed feeding network and MSA element, the CP array can achieve an ultrawideband CP performance with a low profile of 0.05λ L . The measured results show that the proposed MSA array achieves the 10 dB impedance bandwidth of 97.2%, 3 dB axial ratio bandwidth of 83.2%, and 3 dB gain variation bandwidth of 73.8%. Compared with the other designs in published literatures, the proposed CP MSA array owns the advantages of low profile with a simple structure and good CP performance without any air gap, thus indicating a promising candidate in compact wideband wireless systems.