A Novel Electromagnetic Band Gap Structures for Two-element MIMO Antenna

In this paper, a novel electromagnetic band gap (EBG) structure is proposed to reduce the mutual coupling between two element MIMO antenna. The proposed array antennas consist of two rectangular patch antennas and three EBG structure units inserted between them on the substrate. The proposed MIMO antenna is designed on FR4-epoxy substrate with a thickness of 1.1 mm, permittivity is 4.4 and loss tangent is 0.02. In this design, rectangular patch antenna using coaxial feed mode and the distance between the two antennas is 15 mm, it ensures that the distance between the two antennas of the MIMO antenna is close and the space utilization is high. The mutual coupling of antenna in 2.45 GHz is -14.5 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 2.45 GHz is reduced to -28.5 dB. Thus, the proposed antenna array isolation greatly improved by use of the EBG structure. The proposed MIMO antenna can be used in a wireless local area network communication system.