This work explains the design and development of a small, wide-ranging antenna for millimeter wave (mm-Wave) and 5G technology and their applications, along with the configuration to set up as a multiple-input multiple-output (MIMO) system. Rogers RT/duroid 5880 substrate material, which has a height of 1.575 mm, is used for fabricating the antenna. It possesses a compact overall size of 36 × 36 mm2. The design process began with the creation of a octagonal conventional mm-wave microstrip antenna. Subsequently, the impedance bandwidth was enhanced by incorporating the slots of rectangular shape on either parallel edges to the patch feed enabling it to perform over a larger bandwidth ranging between 25 GHz to 32 GHz. Moreover, a new metasurface and a structure shaped like a swastika are positioned between the 2 × 2 arrangement to minimize mutual coupling. The suggested MIMO antenna provides a wide frequency range, significant gain, minimal interference between antennas, and a low correlation between signal envelopes while also achieving a high level of diversity gain. Furthermore, the proposed study has been compared to similar works to demonstrate the significance of the proposed research.