A Four-Element Dual-Band Filtering MIMO Antenna with Isolation Enhancement

In this paper, a four-element dual-band multiple-input-multiple-output (MIMO) antenna with integrated functions of filtering, covering 2.4 GHz WLAN and 3.5 GHz WiMAX bands is presented. The proposed antenna consists of four filtering antenna elements and decoupling network. Coupled stub-loaded resonators embedded in the feeding network of the antenna element are employed to achieve dual-band filtering response and high skirt selectivity. A metal strip decoupling network is designed in the ground plane to reduce the mutual coupling between antenna elements and enhanced isolation performance across the operation bands is obtained. The prototype is simulated, fabricated, and measured. A good agreement between EM simulated and measured results evidently validates the proposed filtering MIMO antenna. The envelope correlation coefficient (ECC) is also investigated, showing an accepted level for WLAN and WiMAX applications.