Bandwidth and gain enhancement of triple-band MIMO antenna incorporating metasurface-based reflector for WLAN/WiMAX applications

In this work, a compact two-element triple-band multiple-input multiple-output (MIMO) antenna loaded with reflective type metasurface (MS) for enhancing the gain, isolation and impedance bandwidth (IBW) is presented. The two-element radiator antenna consists of a microstrip feed line on the upper side of the substrate and defected ground structure (DGS) on the backside on which multiple slots are etched for obtaining triple-band antenna performance. Due to DGS loading, the entire dimensions of the single radiator antenna are reduced to 22 x 22 x 1.6 mm(3) with smaller electrical dimensions of 0.17 lambda(0) x 0.17 lambda(0) x 0.012 lambda(0) at the first resonating frequency. The proposed two-port MIMO antenna with MS operates at 2.36-2.50, 3.43-3.50 and 5.15-5.88 GHz with percentage bandwidths of 5.76, 2.02 and 13.22% for the three operating bands. Due to MS loading, a gain improvement of 5.49, 4.57 and 0.80 dBi is noticed with a maximum gain of 3.98, 5.25 and 2.66 dBi is obtained at the three operating frequencies of 2.46, 3.51 and 5.32 GHz, respectively. The intended antenna is appropriate for working in IEEE 802.11 b/g/n (2.4-2.484 GHz) WLAN, IEEE 802.11 a/h/j (5.15-5.825 GHz) WLAN, and IEEE 802.16e (3.4-3.5 GHz) WiMAX wireless applications.