Research On Compact Wideband MIMO Antenna

With the rapid development of wireless communication technology,4G technology has become mature.In the future mobile Internet and Internet of things era,4G network transmission rate has been unable to meet the requirements of consumers.Research on the fifth generation of communication systems(5G)is imminent.There are two ways to increase the signal transmission rate.: Increasing channel bandwidth and transceiver antenna.As spectrum resources become increasingly depleted,it would be very difficult to further improve channel bandwidth.MIMO antenna as a result of the need to increase the additional frequency bandwidth can improve the signal quality of communication and become the domestic and international research hot spots in recent yearsAt present,there are many challenges in the design of MIMO antenna.First,with the mobile smart devices more and more miniaturization and thin,leaving the antenna design space is getting smaller and smaller.Second,the increasingly small antenna design space will inevitably lead to high mutual coupling between the antenna elements,the internal electromagnetic environment will become more complex,the antenna's radiation characteristics will be severely damaged.So how to improve the isolation between the antenna elements in a small space has become the focus of this paper.1.A planar slot MIMO antenna with dual frequency characteristics is designed.An antenna element having a dual-frequency characteristic is obtained by loading an L-shaped metal strip on an existing open-end gap.Decoupling of the idea: the use of three cracks to suppress the low-frequency resonant mode surface current,and high-frequency resonant mode of the gap position is relatively far,by the mutual coupling smaller.The simulation results show that the MIMO antenna can effectively cover the 2.4G-WLAN and 5.8G-WLAN bands,and obtain more than 17.2dB and 38.5d B in the low and high frequency bands,respectively.The isolation of the MIMO antenna to meet the design requirements.2.Based on the bending line technology,a MIMO antenna covering 2.4G-WLAN and 5.8G-WLAN bands is proposed.Decoupling: In order to better improve the isolation between the antenna elements,the use of antenna layout will produce low-frequency mode of the branches on the far end of the antenna,but will lead to high-frequency resonant mode of the branches have a strong mutual coupling,Using neutralization techniques to suppress these couplings.The results of simulation and test show that the dual-band MIMO antenna effectively covers the 2.4G-WLAN and 5.8G-WLAN bands,and the isolation in these two operating bands is greater than 15 d B.Well applied in the WLAN system.3.A two-unit compact broadband MIMO antenna and a four-unit compact broadband MIMO antenna are designed by means of floor and orthogonal polarization.The antenna unit uses a wide-width circular planar monopole antenna,by controlling the size and position of the circular groove to obtain the desired frequency.Decoupling ideas: the use of orthogonal polarization and floor constraints to suppress the antenna between the near-field coupling and surface-wave coupling.Finally,the design of the two broadband MIMO processing test,test and simulation results show that the two-unit compact broadband MIMO antenna can cover 2.74-5GHz band,in the working frequency band can get greater than 20 d B of isolation.Four-unit compact wideband MIMO antenna can effectively cover the 2.54-3.2GHz band in which the mutual coupling between the antenna elements is less than 15 dB to meet the requirements of the MIMO antenna design.