Dual-Polarized Crossed-Dipole Base Station Antenna Array With High-Isolation and Wide-Angle Scanning

To realize the wide-angle beam-scanning characteristics of the dual-polarized base station antenna array, antenna elements are required to have a wide-beam property, and element spacing should be small. In this case, the strong mutual coupling between closely adjacent elements becomes the most critical issue. In this study, a combination of the multifunctional decoupling parasitic structure (MDPS) and the crown-type decoupling parasitic structure (CDPS) was introduced to the dual-polarized crossed-dipole antenna array to improve isolation between two adjacent elements. MDPS is critical for miniaturizing of the antenna unit, broadening its beamwidth, and decoupling between adjacent cross-polarized elements. The CDPS decouples adjacent co-polarized elements. The parasitic structure can be directly integrated into the antenna without introducing other structures between antenna units. Crucially, the proposed decoupling method does not degrade the beam-scanning capability of the antenna array. In this study, <tex-math notation="LaTeX">1× 4 </tex-math> and <tex-math notation="LaTeX">6× 4 </tex-math> antenna arrays were designed, fabricated, and measured. The measured results revealed that the proposed antenna arrays can cover the 3.3–3.6-GHz 5G mobile service frequency band and exhibit an isolation greater than 20 dB between all adjacent units as well as a scanning angle of ±55°.