In this document, a Multiple Input Multiple Output (MIMO) antenna is proposed in the 3.5 GHz band for wireless applications in 5G connected devices. This MIMO antenna system consists of two antennas disposed next to each other, and the dimensions of each antenna were 50 mm ×40 mm× 1.6 mm. It has a full size of 100 mm ×80 mm× 1.6 mm and a spacing of λ/8 between radiating elements, where λ is the length of waves in a vacuum. The proposed antenna is designed on a FR4 type substrate with a permittivity of 4.3 and a microstrip line is used to feed the patch. An effective technique is used to increase the decoupling between antennas. This technique is base on the inserting of an arrangement of SRR (Split Ring Resonator) cells to minimize the isolation between the MIMO antenna elements. A simulation, analysis, and fabrication process are used to create both individual and MIMO antennas. A simulation result shows that the gain remains above 3.5 dB and the efficiency reaches above 80% in the working band. Thus, a good reduction of the mutual coupling of 23 dB with SRRs is achieved. Also, a good agreement is achieved between measurements and simulation results. Our work shows the influence of each technique on the characteristics of our antennas to find the best configuration to be suitable for 5G and IOT applications.