An eight-element meandered fed concentric annular ring slot resonator MIMO (multiple input multiple output) antenna array with dual-band operation is presented for sub-6 GHz 5G and unlicensed C-band Wi-Fi applications. The annular slot radiators are fed by meandered elements designed for operation at 3.15–3.9 and 6.27–6.6 GHz frequency bandwidth with enhanced isolation of more than 20 and 15 dB in the respective bands. The resonator rings are placed on the four corners of the smart-phone PCB with orthogonal meandered elements. The double-band operation is because of two rings and the isolation has been improved by meandered feed elements. The performances of the proposed MIMO antenna was analyzed and validated experimentally. The design offers sufficient gain of more than 5 dBi and efficiencies of upto 75% with better radiation coverages. The measured results of the MIMO antenna are found to be in good agreement with the simulated results. Further, the antenna has been studied for SAR effects as well as radiation coverages in the proximity of users head and hand-head. The antenna housed on $130\times 70{\mathit{mm}}^2\left(1.47{\lambda }_0\times 0.79{\lambda }_0\right)$ common ground plane has provided good characteristics making it a potential candidate for sub-6 GHz C-Band 5G and unlicensed Wi-Fi smart-phone applications.