A wideband multiple input multiple output (MIMO) antenna was designed and fabricated for a wireless device at the operating frequency bands 2.1/2.3/2.6 GHz for LTE and 2.4GHz for Wi-Fi. The designed MIMO antenna has single element with quad-ports wideband for portable devices. The MIMO antenna involves a symmetrical four port microstrip feedline monopole patch antenna with single radiating component and a frame-shaped partial ground plane. The designed MIMO antenna was modeled and simulated using CST's simulation software and then the antenna prototype was fabricated and measured. The results indicated that the measurement results were found to be in a reasonably fair agreement with simulation results. Both simulation and measurement results were used to verify the MIMO antennae's performance parameters; the operating bandwidth was found to be 2-3.0 GHz with reflection coefficients lower than -10dB and isolation below -12 db. An envelope correlation coefficient (ECC) smaller than 0.2 and diversity gain of about 10 dB were achieved.