A simple compact H shaped MIMO antenna for WLAN application at resonating frequency 5.8 GHz is propose in this paper. The center to center spacing between closely placed H shaped MIMO antenna is 0.311λo. The mutual coupling between the proposed antenna is reduced by using dumbbell shaped DGS at the center of the groundplane. These dumbbell shape defect act as bandstop filter because of its inductance and capacitance effect, helps to suppress the surface wave propagation of waves. The filter characteristic of the dumbbell shaped DGS is studied to achieve isolation over the 5.725-5.875 GHz frequency band. Further the parametric study such as length, width and the spacing of dumbbell shaped DGS is optimized and studied in order to achieve good isolation among the MIMO antenna elements. The proposed MIMO structure is fabricated on low cost FR4 substrate having thickness of 1.6mm and the overall dimension of MIMO antenna is 40mm x 24 mm leading to compact size of antenna. The mutual coupling reduces from 24 dB to 34 dB by placing dumbbell shaped DGS. The envelope correlation coefficient for the proposed antenna is below less than 0.04 dB for the operating frequency band. The proposed H shaped MIMO antenna is tested and the measured result follows the simulation results. Therefore the proposed antenna is a good candidate for WLAN application.