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

This paper introduces a metasurface (MS)-based circularly polarized microstrip patch antenna with partial ground. The antenna consists of a square microstrip patch in a 1.6 mm thick FR-4 substrate with a cross-shaped slot. A metasurface layer, composed of a $5 \times 5$ square array, is designed on another $1.6 \mathbf{~ m m}$ thick FR-4 substrate placed above the host antenna as a superstrate layer. The proposed antenna demonstrates a $\mathbf{- 1 0} \mathbf{~ d B}$ impedance bandwidth spanning from 5.34 GHz to 7.80 GHz, along with an axial ratio (AR) bandwidth from 5.95 GHz to 6.29 GHz. At 6.20 GHz, the antenna achieves a maximum realized gain of 5.90 dBic, exhibiting a right-handed circular polarization (RHCP) feature. With its compact dimensions $\left(0.77 \lambda_{0} \times 0.77 \lambda 0 \times 0.032 \lambda_{0}\right.$ at 6.12 GHz), the circularly polarized antenna proposed here is well-suited for long range radio communication and in satellite for uplink transmission.