A four-port DGS (defective ground structure) MIMO antenna is the subject of an inquiry. The proposed design in this study operates at a range of frequencies (1.8 GHz NB-IoT band, 2.4 GHz ISM band, 3.1 GHz sub 6 GHz, Wi-Max, and 4.8 GHz 5G connectivity band). The antenna is driven by an excited microstrip transmission line. All ports of the recommended MIMO antenna are isolated by less than -15dB, and its tiny (20 cm by 15 cm) footprint. It also takes into account radiation characteristics including s-parameters, radiation pattern, directivity, gain, return loss, and bandwidth. Measurements of MIMO performance such the Envelop correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), and mean effective gain (MEG) are also employed to ensure proper diversity performance. Utilizing CST Microwave Studio, the proposed antenna is examined. The resonant frequencies of antennas 1, 2, 3, and 4 are 1.8 GHz, 2.4 GHz, 3.1 GHz, and 4.8 GHz, respectively. The greatest gain it provides is 9.15dB. There is 20 dB isolation between ports.