A Dual-Band Dual-Polarized Base Station Antenna Array With Isolation Enhancement

In this paper, a dual-band dual-polarized antenna with isolation enhancement is designed. The proposed antenna operates in the frequency range of 3.4–3.6 GHz and 4.8-5 GHz, where the center frequency of the high band (HB) is 1.4 times that of the low band (LB). Two radiating patches are placed in different layers to create the two distinct resonances and the bottom patch which is shorted to the ground by four metal posts acts as the ground for the top patch antenna. A metal wall is introduced between LB feeding probes to enhance the polarization isolation to more than 25 dB. Complementary split-ring resonator (CSRR) structures are etched on the feedlines to improve the cross-band isolation to over 25 dB. Based on this antenna element, a
$1\times 4$
-element linear array is constructed with SRR-loaded baffles positioned between adjacent elements to suppress the mutual coupling. Measured results show that the proposed antenna and its array are good candidates for 5G base station applications.