Wideband Dual-Polarized Cross-Shaped Vivaldi Antenna

Abstract

This communication presents a wideband, dual-polarized Vivaldi antenna or tapered slot antenna with over a decade (10.7:1) of bandwidth. The dual-polarized antenna structure is achieved by inserting two orthogonal Vivaldi antennas in a cross-shaped form without a galvanic contact. The measured $- 10\,\hbox{dB}$ impedance bandwidth ( ${S_{11}}$ ) is approximately from 0.7 up to 7.30 GHz, corresponding to a 166% relative frequency bandwidth. The isolation ( ${S_{21}}$ ) between the antenna ports is better than 30 dB, and the measured maximum gain is 3.8–11.2 dB at the aforementioned frequency bandwidth. Orthogonal polarizations have the same maximum gain within the 0.7–3.6 GHz band, and a slight variation up from 3.6 GHz. The cross-polarization discrimination (XPD) is better than 19 dB across the measured 0.7–6.0 GHz frequency bandwidth, and better than 25 dB up to 4.5 GHz. The measured results are compared with the numerical ones in terms of $S$ -parameters, maximum gain, and XPD.