Abstract : Substrate Integrated Waveguide (SIW) is one of the major promising waveguide technologies for circuit implementation in compact form, replacing bulky waveguide structure to the extent. The closely spaced antenna elements for realizing n×n Multiple Input Multiple Output (MIMO) is a challenging task. The design of hairpin slot antenna elements closely spaced for MIMO application is presented. The main aim of work is to achieve good isolation for improving the diversity of coupling effects. SIW configuration supports the feature for reducing the mutual coupling effects, intern improves the isolation between the antenna elements. A 2×2 MIMO configuration have been considered and the dual antenna elements are designed on a single substrate based on SIW, operating at 5.8GHz band. The performance in the isolation, matching and radiation pattern are evaluated, compared and studied. © BEIESP.