Compact dual-band printed monopole array with high port isolation

This paper proposes an efficient techinique utilizing U-shaped resonator and spilt ring defected ground structure (SRDGS) to reduce the mutual coupling in a 4-shaped dual-band MIMO antenna array. The U-shaped resonator and SRDGS are located beneath the substrate. The U-shaped resonator is used to decrease the mutual coupling at 5.4 GHz, while the exploiting of SRDGS structure can reduce the mutual coupling at 2.5 GHz. The simulated results show the mutual coupling between array elements has been obviously reduced at the two operating frequency bands with the implementation of the proposed U-shaped resonator and SRDGS structure.