A low mutual coupling MIMO antenna using EBG structures

This paper presents a low mutual coupling MIMO antenna using an electromagnetic band gap (EBG) structure. The proposed antenna array consists of two rectangular patch antennas and three EBG units on the dielectric substrate. EBG structure has high impedance surface to form surface wave frequency band gap, compared with other decoupling structure, the decoupling effect of EBG structure is better. The performance and dimensions of the EBG structure are optimized by the use of High Frequency Structure Simulator (HFSS). Simulation results show that the proposed EBG structure can reduce the mutual coupling effect of MIMO antenna, and the antenna has high isolation. A method using EBG structure to reduce the mutual coupling between two element antenna arrays is proposed, which makes the mutual coupling between the antenna units at the antenna operating frequency of 5.5 GHz decrease obviously. The proposed EBG structure consisted of slots loaded in surface which is evolved from the typical Mushroom-EBG structure. The mutual coupling of antenna in 5.5 GHz is about −16 dB without EBG structure which mutual coupling effect is obvious. By inserted three EBG units between the two patches, the mutual coupling of antennas in 5.5 GHz is reduced to about 32dB. Therefore, by using the EBG structure, the isolation between the two antenna elements is greatly improved.