A very compact ultra-wideband (UWB) multiple-input-multiple-output (MIMO) ground linearly tapered slot Antenna (LTSA) is presented in this paper. On a cost-effective FR4 substrate, it consists of a ground plane and two microstrip feedlines. Its overall dimension is only 22×26 mm2. To miniaturize the dimension of the antenna, two linearly tapered slots on the ground plane act as the main radiator. Then it does not need extra large radiation patch. In particular, a simple embedded three-level stepped slot on the central ground, brings high isolation in the whole UWB band. In addition, two rectangular slots cut in the feedlines widen the impedance bandwidth. Simulated and measured results verify S11<-10 dB and S12<-18 dB at 3.1 GHz-12 GHz and good diversity performance. Therefore, the proposed MIMO antenna has potential for portable devices applications.
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