| With the rapid development of wireless communication technology,China will enter the first commercial year of 5G in 2019.At present,the frequency band of 5G is5 G low frequency band.Compared with the current 2G / 3G / 4G / 5G band,millimeter wave band has a large number of available spectrum resources,which can effectively alleviate the current situation of low-frequency spectrum congestion,so as to meet people's demand for high-speed communication.Therefore,millimeter wave technology has attracted people's attention.MIMO technology can significantly improve the capacity and reliability of the communication system without increasing the spectrum resources,and obtain obvious diversity gain.It has been widely used in the fourth generation mobile communication and other communication systems.Millimeter wave technology combined with MIMO technology makes ultra-high speed wireless communication possible,so the design of millimeter wave MIMO antenna has certain significance.This paper focuses on the design of millimeter wave MIMO antenna,and designs several kinds of millimeter wave MIMO antenna and multi element antenna array.The main work is as follows:Firstly,based on the millimeter wave tree fractal element antenna,two kinds of four element MIMO antenna and one kind of eight element MIMO antenna are designed,which are parallel four element MIMO antenna,parallel eight element MIMO antenna and vertical four element MIMO antenna.The S-parameter curve,radiation pattern and gain pattern of each MIMO antenna are given.The-10 d B bandwidth of the parallel Quad MIMO antenna is 4.6 GHz(26.8 GHz–31.4 GHz)and the center frequency is 29 GHz.By slotting the ground plane and loading isolation branches,the isolation parameters of the parallel Quad MIMO antenna are lower than-17 d B.The simulation results show that the-10 d B bandwidth of the parallel eight element MIMO antenna is 3.6 GHz(26.8 GHz–30.4 GHz)and the center frequency is 29 GHz.The isolation parameters of the parallel eight element MIMO antenna are lower than-16 d B.The simulation results show that the-10 d B bandwidth is 5.2GHz(26.2 GHz–31.8 GHz)and the center frequency is 28.6 GHz.In terms of isolation parameters,the isolation parameters of vertical quaternion MIMO antenna are lower than-17 d B,which meets the requirements of MIMO system for antenna isolation.Secondly,based on the dipole broadband millimeter wave element antenna,two kinds of four element MIMO antennas and one kind of eight element array antenna for mobile terminal are designed.Two kinds of quaternion MIMO antennas are parallel quaternion MIMO antenna and vertical quaternion MIMO antenna.The surface current distribution,S-parameter curve,radiation pattern and gain pattern of each MIMO antenna are given.The-10 d B bandwidth of the vertical quaternion MIMO antenna is 13.6 GHz(29.4 GHz–43 GHz),and the isolation between antenna elements is below-19 d B.The-10 d B bandwidth of the parallel Quad MIMO antenna is 12.8GHz(29 GHz–41.8 GHz),and the isolation between port 1 and other ports is less than-15 d B.The-10 d B bandwidth of the eight element array antenna is 13GHz(29GHz–42 GHz),and the two center frequencies of the array antenna are 31 GHz and38 GHz respectively.The isolation between antenna units is less than-15 d B,and the isolation between antenna units is less than-20 d B at high frequency.The three-dimensional radiation patterns at 31 GHz,35 GHz and 39 GHz and scanning angles of 0 °,-15 ° and-30 ° are given respectively.The proposed array antenna has good beam scanning characteristics,sidelobe mode and high directivity. |
PDF Full Text Request