Low-profile dual-polarized patch antenna with HIS reflector for base station application

Abstract

A coax-feed low-profile dual-polarized patch antenna with high impedance surface (HIS) reflector is presented. The proposed antenna contains two pairs of narrow slots along the diagonals and two pairs of T-shaped slots along the centerlines, which keep the cross-polarization under −38 dB. By introducing two short pins, the isolation between the two ports remains more than 36 dB in the whole bandwidth. Low profile and high front–back ratio characteristics are achieved by using the HIS reflector, which is also applied to enhance the performance of two-element array. The height of the antenna is less than λ/8 and the front–back ratio is better than 35 dB. The mutual coupling lower than −31 dB is obtained for the array design with the patches placed 0.8λ apart. The proposed antenna which covers a −10-dB reflection coefficient bandwidth of 2.28–2.75 GHz can be used as the low-profile base station antenna for WiMAX and LTE applications.