A Low-Profile Wideband Dual-Polarized Antenna Based on an Improved HIS and Its Broad-Angle Beam-Scanning Array

A low-profile wideband dual-polarized antenna with an improved high-impedance surface (HIS) reflector is proposed. Dual-polarized radiation is excited by feeding a set of crossed dipoles. Low profile is achieved by utilizing an improved HIS reflector. Good impedance characteristics are realized by inserting small square cells among the primary hexagonal cells of the HIS. Two shorting pins and four parasites are introduced to increase port-to-port isolation and improve impedance matching, respectively. A prototype with profile 7.5 mm (about 0.06$\lambda$ and $\lambda$ equals to the wavelength at center frequency) was fabricated and measured. The experiment results show that the antenna element achieves 43$\%$ bandwidth ($\vert { S_{11}}\vert$<; $$-$10 dB) from 2.0 to 3.1 GHz. The polarization isolation between those two ports is larger than 25 dB. The element was then extended to an eight-element phased array. The measured results demonstrate that the array can scan $\;\pm\text{50}^{\circ }$ for either polarization from 2.0 to 2.6 GHz.