Compact Wide-band MIMO Antenna with High Port Isolation

Abstract

In this letter, a compact planar wide-band multiple-input-multiple-output (MIMO) antenna array with high isolation is presented. The electrically small MIMO antenna array, consists of four half-circular monopole radiators and four separated ground planes. It is in this way that the polarization diversity of the nearby placed radiators is introduced, resulting in high isolation. Four separated grounds are designed to reduce the surface wave coupling, and four ground stubs are etched to reduce the near field coupling. The operating frequency band is also widened by the stubs. The impedance bandwidth (S 11 <;; -10 dB) of the proposed antenna is 2.54 - 3.2 GHz. And better port isolation of above 15 dB is obtained. The antenna exhibits a quasi-omnidirectional radiation characteristic. Moreover, the envelope correlation coefficient is smaller than 0.01, which indicates that a good diversity gain of the proposed antenna is observed. The simulation and measurement results show that the proposed MIMO antenna has a good application prospect in portable devices.