A Wideband Dual-Circularly Polarized Series-Fed Corner-Truncated Patch Array Using Coplanar Proximity Coupling

A wideband, series-fed, single-layer, dual-circularly polarized (dual-CP) antenna based on proximity coupling is presented. The proposed antenna is formed by a cross-shaped corner-truncated patch array (CTPA), a folded microstrip feeding structure, and a soft-surface structure. The CTPA is for the first time proposed in designing such a coplanar single-layer series-fed dual-CP antenna, which achieves a simple structure, wide operating bandwidth, high antenna efficiency, and low cost. To address the issue of beam deflection, which is widespread in previous designs, a dedicated soft-surface structure is employed to encircle the primary radiator. Measured results show that the antenna achieves a wide operating bandwidth from 4.87 to 5.86 GHz (18.5%) while maintaining stable boresight radiation patterns throughout the entire operating bandwidth.