Compact Enhanced‐Gain Dual Circularly Polarized Slotted‐Patch Antenna With Cavity‐Based Metallic Superstrate

ABSTRACT A dual circularly polarized (CP) slotted‐patch antenna with a cavity‐based metallic superstrate is presented. The standalone patch operates at 412 MHz with a 3‐dB axial ratio (AR) bandwidth of 3 MHz and suitable impedance matching. A metallic superstrate, placed at λ⁄7 above the patch, enhances the realized gain by approximately 5 dBi, while preserving circular polarization performance with minimal AR bandwidth degradation. Measured results validate the simulation predictions, indicating a reduction of the half‐power beamwidth (HPBW) to 75°. Despite the predicted side lobe level (SLL) increase from −15 dB to −10 dB, measurements show improved SLL performance. The proposed configuration offers a compact and cost‐effective solution for enhanced‐gain CP antenna applications.