An X-band Dual-Polarized Ultra-Wideband Differentially-Fed Array Antenna

In this paper, an X-band dual-polarized ultrawideband differentially-fed antenna array is presented. The antenna consists of two pairs of ± 45°-orthogonal differentially-fed taper-shaped patch dipoles. To broaden the operating bandwidth of the antenna, a folded coaxial feeding structure and the shorted parasitic patch are introduced into the antenna design, enabling an operating frequency band from 7.6 GHz to $18.1 \mathrm{GHz}(81.7 \%)$ with $S_{11 d d}$ below - 10 dB. Due to the differential feeding mode, the antenna structure achieves central symmetry, ensuring the consistency of performance and a high isolation between the two polarizations. The proposed antenna element has been adopted to construct a $4 \times 4$ ultra-wideband dual-polarized antenna array with 64 ports, and verified by experiments. The measurement results show good consistency with the simulation results.