Wideband Circularly Polarized Metasurface‐Integrated Dipole Antenna for Bidirectional Applications

This study proposes a compact dipole antenna incorporating a wideband polarization‐converting metasurface designed for bidirectional applications. The antenna comprises a stepped‐width modified dipole structure with two strategically positioned parasitic patches located on the bottom side of the substrate and a metasurface polarization converter comprising four square metal plates arranged in a 2 × 2 layout on the top side. Each unit cell features a diagonally structured pattern created by etching lines into the metal plates, enabling phase manipulation and amplitude balancing for efficient linear‐to‐circular polarization conversion. The antenna achieves left‐hand circular polarization on the broadside and right‐hand circular polarization on the opposite side, making it suitable for bidirectional applications where polarization diversity is critical. The proposed antenna design achieves an axial ratio bandwidth of 45.7% (4.06–6.45 GHz), an | S 11 | < −10 dB impedance bandwidth of 46.1% (4.03–6.43 GHz), and a peak gain of 3.3 dBic at 5.2 GHz. This compact configuration, with dimensions of 32 × 32 × 0.508 mm (0.54 λ o × 0.54 λ o × 0.0086 λ o at 5.1 GHz), enables bidirectional applications in wireless communication.