A tiny EBG‐based structure multiband MIMO antenna with high isolation for LTE/WLAN and C/X bands applications

This article proposes a compact multiple-input multiple-output (MIMO) antenna with the electromagnetic band gap (EBG) structures for mobile terminals. The proposed MIMO antenna is composed of two radiation patches in which diagonal and folded microstrip lines are utilized to control the frequency bands. The radiation patch, one EBG structure and a rectangular-shaped ground plane are etched on both sides of the antenna. The EBG structures have been employed for reducing the mutual coupling between the antenna elements. As a result of the effect of these structures, the mutual coupling between the two elements is reduced by less than -30 dB. The proposed antenna is implemented on an FR4 substrate with dimensions 20 x 10 x 1 mm(3). According to measured results, frequency ranges of 2.2 to 3.6 GHz and 5.1 to 5.9 GHz with S-11 < -10 dB and also 3.7 to 5 GHz and 8 to 12 GHz with S-22 < -10 dB have been obtained. Moreover, measured S-12 and S-21 with values of less than -30 dB for both Ports have been realized. Additionally, the envelope correlation and radiation efficiency of the purposed antenna are less than 0.09 and more than 82%, respectively.