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Isolation enhancement in dual-band MIMO antenna by using metamaterial and slot structures for WLAN applications

A dual-band multiple-input multiple-output (MIMO) antenna with enhanced isolation operating in 2.35–2.50 GHz and 5.13–5.88 GHz bands is investigated and presented. The proposed antenna system is deformed from two inverted-F antennas, and the distance between the antenna elements is only 0.104 λ ( λ —wavelength of 2.4 GHz). To enhance isolation and reduce mutual coupling, the metamaterial and slot structures are efficiently and innovatively designed on the ground plane for two bands. Both decoupling methods effectively improve the antenna isolation, with metamaterials acting on the lower band and slots acting on the higher band. The mutual coupling at 2.4 GHz and 5.5 GHz is reduced by 15.24 dB and 8.19 dB, respectively. Then, the optimized MIMO antenna can cover both 2.4 GHz and 5 GHz wireless local area network (WLAN) bands, and has the advantages of wideband, compact size, good radiation, enhanced isolation, and low envelope correlation coefficient. The measured results agree with the simulated results, which shows that the proposed MIMO antenna system has potential application value in WLAN system.