This paper presents a multi-element multiple-input multiple-output (MIMO) antenna with self-isolation and flexible characteristics. The primary radiators of the proposed antenna consist of multiple ellipse-shaped patches arranged in an H-plane configuration. Self-decoupling is achieved by simultaneously different operating modes on the excited element (TM10 mode) and non-excited element (TM02 mode). The proposed method also shows strong extensibility. The measurements on the fabricated 4-element MIMO antenna demonstrate that the proposed decoupling method can improve the isolation by 14 dB. The antenna shows good MIMO diversity performances with respect to the envelope correlation coefficient and diversity gain. Additionally, the antenna also works effectively in when the substrate is bent, which contributes to significantly increasing the applicability of the proposed method in comparison with the other reported methods.