As wireless communication systems evolve rapidly, leading to an increasing demand for compact multi-band antennas. These designs must support services such as WLAN, WiMAX, and X-band operations simultaneously reducing system complexity and physical size. However, a significant challenge in developing such multi-channel MIMO (Multiple-Input Multiple-Output) systems is the presence of multi-path fading and the high mutual coupling between closely spaced antenna elements, both of which can severely degrade overall performance. To address these issues, this project presents a compact quad-band MIMO antenna designed on an FR4 substrate with overall dimensions of L=60mm, W=60mm, H=0.8mm. The design utilizes two horizontally placed, slotted F-shaped radiation patches fed by microstrip lines. To achieve the four required operating bands, we implemented a strategy of slotting the main patches to create a third band for the 5.25 GHz band, while the two original branches of the F-shape handle the 3.5 GHz and 7.5 GHz bands and 8-12GHz X-band. Furthermore, to overcome the challenge of mutual interference, a Defected Ground Structure (DGS) is integrated into the design, ensuring high isolation between the ports and reliable MIMO performance.