Wideband MIMO Directional Antenna Array with a Simple Meta-material Decoupling Structure for X-Band Applications

In this paper, a compact wideband MIMO directional antenna array with a single-layered meta-material is proposed to realize high isolation. The meta-material decoupling structure, which is composed of a modified split-rings and a square loop structure, is suspended over the two antenna elements to reduce the mutual coupling. The achieved results show that the proposed antenna array owns a −10 dB impedance bandwidth ranging from 8.5 GHz to 11.5 GHz. Furthermore, by loading the proposed meta-material superstrate over the two-element MIMO antenna, the designed MIMO antenna array not only has good performance but also enhances the isolation to be more -15 dB within the operating frequency band. In addition, the performances of the proposed antenna array are also tested by radiation pattern, gain, envelope correlation coefficient, diversity gain, total active reflection coefficient and so on. Therefore, these simulation results prove that the proposed wideband MIMO directional antenna array is a suitable candidate for X-band communication.