The present invention relates to a Multiple-Input Multiple-Output (MIMO) omnidirectional antenna comprising three or more column sets arranged in a centrosymmetricly. Each column set comprises two or more antenna columns, each having a plurality of radiators mounted thereon. Each antenna column receives no more than two signals to be transmitted, and is arranged axisymmetricly about a radially-directed axis created between the center point of the antenna and a transverse cross-sectional midpoint on the antenna column. Therefore, each radiation pattern established by each of the three or more column sets is centrosymmetric about the center point of the antenna and axisymmetric about the radially-directed axis. The MIMO omnidirectional antenna can fit within a radome of small diameter, while providing relatively uniform radiation plot coverage across a microcell where it is deployed. As no phase shifting is utilized, there is little ripple effect and all of the ports have a similar gain.