Design of compact dual‐polarized base station antenna array with high isolation using array decoupled surface and parasitic patch structure

For a compact base station antenna array, the isolation between two co-polarized adjacent elements and two cross-polarized adjacent elements is relatively poor. The introduction of the array decoupled surface (ADS) on the top of the antenna and the introduction of parasitic structures between adjacent elements effectively improve the isolation of the co-polarized and cross-polarized adjacent elements. Array decoupled surface mainly suppresses the mutual coupling between the co-polarized adjacent elements, and the parasitic structure mainly suppresses the mutual coupling between the cross-polarized adjacent elements. Both simulated and measured results show that in the 3.3–3.6 GHz band, the return loss of all ports is better than 10 dB. By introducing the ADS and the parasitic patch structure, the isolation between two co-polarized adjacent elements is improved from about 15 to 21.9 dB, and the isolation between two cross-polarized adjacent elements is improved from about 13 to 22.4 dB. The isolation between two cross-polarized elements in the same unit is greater than 27 dB.