A planar multipolar antenna for MIMO applications

In this paper, a planar multipolar antenna consists of four elements is proposed for MIMO application. The size of the antenna is compactly confined in a 0.22lambda_o x 0.22lambda_o square. With the concept of multipolar radiation and the introduction of the mode decomposition network, we can generate the desired multipolar pattern with a fully decoupled benefit. Although the bandwidth performance is significantly reduced for higher order multipolar mode, we can always make a tradeoff between bandwidth and compactness of the multi-element antenna.