Compact UWB MIMO antenna for USB dongles with angle and polarization diversity

A compact dual-element antenna suitable for ultrawideband (UWB) MIMO operation is proposed in this work. The size of the antenna is 25 mm by 40 mm and it covers the lower UWB band of 3.15-5.15 GHz. Apart from the inherent wideband isolation obtained through the different angle and polarization characteristics in the radiation patterns of the individual elements, the gap between the two antenna elements is also utilized to enhance both the isolation and impedance bandwidths. Simulation and experimental results reveal that, within the band of interest, the achieved isolation is over 20 dB and the envelope correlation of the radiation patterns is below 0.1.