High isolation multi-input multi-output ultra-wideband antenna with a WLAN rejection band

This paper proposes an ultra-wideband multiple-input multiple-output antenna with high isolation and WLAN rejection band for indoor communication applications. Three parallel slots with different length are etched on the common ground plane to reduce the mutual coupling between the two antennas. An inverted U-shaped slot is inserted into the microstrip feed line to block 5.0-5.6 GHz WLAN band which may give interferes to UWB systems. The proposed antenna consisting of two identical antennas has a small size (40×40×0.4 mm³), whose -10dB bandwidth can cover the entire UWB band. In the pass band, the isolation is better than -19.3dB (-20dB in most of the UWB band).