Research And Realization Of High Isolation MIMO Antenna

Multiple input multiple output (MIMO) technology can increase the channelcapacity and reliability of existing wireless systems without using additional spectrumresources. A difficulty of MIMO technology is the design of MIMO antenna, becausewhen two or more antennas are placed in the space with a small size, that willcause mutual coupling and the performance of the antenna will be bad, therefore, it isimportant to enhance the isolation of MIMO antenna.In this paper, we designed three kinds of MIMO antenna with high isolation basedon theoretical analysis of the previous work.The first antenna is a2-port2.4GHz monopole MIMO antenna with high isolation.The width between the antennas is less than1/4wavelength, and the isolation is less than-20dB in the Bandwidth range, the maximum isolation is less than-25dB, that isS21<-20dB and S21max≤-25dB by using the methods of isolated ground, decoupling branchand a hole connected to ground.The second antenna is a2-port2.4GHz and5.8GHz inverted-F MIMO antenna withhigh isolation. The width between the antennas is less than1/4wavelength, and theisolation is less than-20dB in the2.4GHz Bandwidth range, the maximum isolation isless than-25dB, that isS21<-20dB and S21max≤-25dB. In5.8GHz the Bandwidth range,the isolation is less than-25dB, the maximum isolation is less than-30dB, that is S21<-25dB and S21max≤-30dB by using the methods of isolated ground and ground slot.The third antenna is a4-port2.4GHz inverted-F MIMO antenna with high isolation.The isolation is less than-20dB in the Bandwidth range, the maximum isolation is lessthan-25dB by using the methods of isolated ground and ground slot.