A Low-profile Wideband Dual-polarized Antenna with Coupled Feed Structure for 5G Base Station Application

A low-profile dual-polarized dipole antenna is presented with a specially designed coupled feed structure, featuring a stable radiation pattern tailored for use in 5G base stations. The antenna is constructed with a pair of intersecting dipoles, a feeding mechanism that interfaces with them, an intermediary layer for coupling, and a metallic backing that serves as a reflector. The feeding method of the crossed-dipoles radiator is not in direct contact with the balun feeding structure, but in direct contact with the coupled feed structure on the back of the substrate. Such a feeding method brings about the effect of low profile. The proposed antenna is capable of operating across the frequency ranges of 2.99 GHz to 3.91 GHz, with a reflection coefficient below −15 dB within this spectrum, and it exhibits an average isolation exceeding 33 dB. It has a stable gain of 9.3 ± 1.2 dBi and half-power beamwidth (HPBW) of 57 ± 5.2° within the operational bandwidth, the suggested antenna stands at a mere 0.114λ
0
in height, a significant reduction compared to the conventional 0.25λ
0
, where λ
0
represents the free wavelength corresponding to the center frequency. The cross-polarization discrimination (XPD) of the antenna exceeds 20 dB in the boresight direction and surpasses 10 dB within the ±60° range in the horizontal plane. Therefore, this antenna exhibits substantial potential for integration within 5G communication systems, showcasing promising applications in the field.