A Multiple-Input Multiple-Output Antenna Array with Low Mutual Coupling Using Baffle Structures

A 2×4 dual-polarized multiple-input-multiple-output (MIMO) array with baffle structures is proposed for 5G base station application. The baffle is composed of two metal split ring resonators (SRRs) printed on a 1-mm thick FR4 substrate. It works as band-stop filter which can block the coupling waves from different directions within the array. Some modifications are also made on the ground to further improve the array performance. Simulated results show that the mutual coupling for both the cross-polarization and co-polarization can be reduced to almost −25 dB or lower in 3.4-3.8 GHz.