A broadband gain-enhanced metasurface-based circularly polarized patch antenna for WLAN application

This article presents a broadband gain-enhanced circularly polarized (CP) microstrip patch antenna based on metasurface (MS). A truncated corner square patch with a cross-shaped slot has been employed as the host antenna, configured on a 1.6 mm thick FR-4 substrate backed by a copper ground plane. The MS layer consisting of a 4 × 4 square array has been designed on another 1.6 mm thick FR-4 substrate with identical outer dimensions acting as a superstrate layer. The proposed antenna exhibits a — 10-dB reflection coefficient bandwidth spanning from 4.37 to 7.03 GHz (46.67%), along with a 3-dB axial ratio (AR) bandwidth from 5.13 to 5.78 GHz (12%). At 5.3 GHz, the antenna exhibits a maximum realized gain of 6.8 dBic. Furthermore, polarization of the antenna is characterized as left-handed circularly polarized. To verify the impedance response, an equivalent circuit model of the antenna has been developed step-by-step followed by fabrication of the prototype. The measured results show high degree of similarity with the simulated responses. Being low profile (0.56λo × 0.56λo × 0.028λo at 5.3 GHz), the proposed CP antenna can be utilized for applications of WLAN, Wi-Fi wireless computer networks etc.