MIMO base station antenna employing Mode Selection in Vertically Split Array

Multiple-input multiple-output (MIMO) techniques are key to increasing the data rate and capacity in mobile systems. Focusing on antenna installation, one of the most serious problems is the limitation on installation space for additional antennas at base station (BS) sites. If we try to install more than two branches in one antenna space, the coverage area is decreased and MIMO performance is degraded because the antenna gain and the spatial correlation are affected by the limitation on installation space. This manuscript proposes MIMO Mode Selection in a Vertically Split Array (MMS-VSA) antenna, which increases the number of MIMO branches without increasing the antenna installation space and without reducing the 3G coverage area by employing mode selection in the vertically split array. The effectiveness of the MMS-VSA antenna is evaluated in a system simulation. The simulation results shows the effectiveness of the MMS-VSA antenna in increasing the number of MIMO branches without increasing the antenna installation space and without reducing the 3G coverage area. The evaluation contributes to the smooth upgrade of BS antennas from the current 3G system to the 4G MIMO system.