This article introduces a cylindrical dielectric resonator antenna (CDRA) fed with a rhombic ring-shaped tapered feed for Multiple-Input-Multiple-Output (MIMO) applications. The proposed hybrid MIMO CDRA resonates at four frequency bands 2.5, 5.09, 6.8, and 9.0 GHz with isolation levels of 22, 34.22, 30.55, and 18.55 dB. Isolation enhancements are achieved by introducing “L” shaped slots on the partial ground plane. Parametric analysis is performed to validate the optimized dimensions of the tapered feed without and with DRA and defected ground structure. Diversity performance is examined by using envelope correlation coefficient and diversity gain. The proposed antenna operates in the S, C, and X-bands and is suitable for RF communication mobile broadband services, Wi-Fi, radar, and satellite applications. Good agreement is observed between simulated and measured results.