Split-Ring Resonator-Loaded Baffles for Decoupling of Dual-Polarized Base Station Array

Baffles loaded by split-ring resonator (SRR) are proposed to reduce the mutual coupling for ±45° dual-polarized multiple-input-multiple-output (MIMO) antenna. Each baffle consists of two rectangular SRR printed on one side of a 1 mm FR4 substrate. The final decoupling structure contains four baffles forming a barrier wall that reduces the coupling over the 5G band of 3.4-3.8 GHz. Dual-polarized cross-dipole array with SRR loading baffles is simulated and measured to demonstrate their effectiveness in the coupling reduction. The results show that the mutual coupling can be effectively reduced below -25 dB over the entire bandwidth while maintaining a compact array.