Abstract: A compact ultrawideband multiple-input multiple-output(MIMO) antenna with compact and high isolation is proposed in this paper. The proposed antenna is composed of two slot antenna elements. To improve the impedance bandwidth of the MIMO antenna, these two slot antennas end with a circular shape etched on the ground plane are fed by microstriplines with one circular patch end, respectively. To obtain a high isolation, a slot is etched on the ground plane to suppress surface wave, and pattern diversity is introduced. Simulation and measurement results show that the proposed antenna has an wide impedance bandwidth of 3.1-11 GHz with |S₁₁| less than-10 dB and |S₁₂|less than -25 dB in 7-11 GHz, and-16 dB in 3.1-7 GHz. The envelope correlation coefficient is calculated based on measured S-parameters.