This article presents a compact UWB MIMO antenna. The proposed MIMO antenna covers bandwidth of 3.9–13.4 GHz. The proposed MIMO antenna gives good isolation between two elements from 8-13.4 GHz. In order to reduce mutual coupling over entire operating band a novel decoupling is inserted between them. It provides minimum of -18 dB isolation over entire operating band. The performance of the MIMO antenna is further evaluated in terms of gain, ECC, radiation pattern, and diversity gain.