A multiband MIMO antenna is proposed for various applications of wireless communication. The proposed antenna is useful for WLAN (5.15–5.30 GHz) and C-band (4–8 GHz) for satellite communication technologies. The proposed antenna is designed using 4-radiating elements for 6 GHz frequencies. The antenna consists of a rectangular shaped element with a rectangular cut slot. This antenna is designed for wide bandwidth operation and satisfied for multiband operation. This antenna has various shapes of radiating elements developed as an mm-wave. The various shape cut slots are introduced for radiating elements to improve bandwidth and multiband operation of an antenna. These radiating elements are placed very nearer, therefore, it increases isolation amounts the radiating elements, that effects on the performance of an antenna and its parameter such as correlation coefficient (CC), envelope correlation coefficient (ECC), total active reflection coefficient (TARC), and diversity gain (DG). To improve the isolation parameter, a defected ground structure (DGS) technique is introduced within the ground plane of an antenna. This defects introduced by DGS is rectangular in nature. The proposed multiband antenna is simulated and measured with enhancement of parameters like return loss, isolation, VSWR, total active reflection coefficient (TARC), correlation coefficient (CC), envelope correlation coefficient (ECC), bandwidth, gain, and directivity. This antenna has an advantage of better return loss, isolation, TARC, CC, ECC, and VSWR with better bandwidth for perfectly matched antennas. Antenna research shows that less than −10 dB return loss, isolation and TARC with less than 0.1 CC and ECC.