Compact Four-Element MIMO Antenna Using DGS for WLAN Applications

A compact four-element multiple-input multiple-output (MIMO) antenna is proposed for WLAN applications operating at 5.75 GHz frequency band. The overall volume of the antenna is 26 mm $\times 26$ mm $\times 8$ mm. Isolation between the antenna elements is improved by using defected ground structure (DGS). Operating frequency band of the MIMO antenna is 5.61–5.9 GHz, where isolation greater than 18.2 dB and envelope correlation coefficient (ECC) less than 0.02, and average channel capacity loss (CCL) less than 0.45 bits/s/Hz are obtained. The average peak realized gain of the four-element MIMO antenna is 1.61 dBi at 5.75 GHz with more than 76 % radiation efficiency in the entire operating frequency band.