A Partially Grounded Wideband Metasurface-Based Circularly Polarized Patch Antenna With Enhanced Gain

This paper introduces a circularly polarized microstrip patch antenna with a partial ground plane, designed using a metasurface (MS) approach. The antenna features a truncated square microstrip patch integrated into a 1.6 mm thick FR-4 substrate, with a square corner cut slots. A metasurface layer, consisting of a $4 \times 4$ patch with ring slot array, is positioned above the antenna as a superstrate on a separate 1.6 mm thick FR-4 substrate. The proposed antenna demonstrates impedance bandwidth ranging from 4.50 GHz to 7.06 GHz and an axial ratio (AR) bandwidth between 5.14 GHz and 5.40 GHz. At 5.25 GHz, it offers a peak realized gain of 7.14 dBi with left-handed circular polarization (LHCP). To confirm the impedance performance, a corresponding prototype of the antenna was fabricated, and the measured results closely align with the simulated outcomes. Featuring compact dimensions of $0.66 \lambda_{\mathrm{o}} \times 0.66 \lambda_{\mathrm{o}} \times 0.028 \lambda_{\mathrm{o}}$ at 5.25 GHz, this circularly polarized antenna is highly suitable for satellite uplink transmissions.