MIMO Antenna For Mobile Terminal

With the rapid development of wireless communication technology,the requirement of wireless communication in modern society is more higher.MIMO can improve the channel capacity and data transmission greatly without increasing the bandwidth and improving the power.Therefore,MIMO technology becomes the focus of researchers.And it was regarded as one of the core of 4G technology.The MIMO antenna has received more attention as the receiver of MIMO communication system.In this paper,the miniaturization and high isolation of the mobile terminal antenna is what we focus on.The paper includes three parts of work.Firstly,a wideband U-shape slot MIMO antenna based on the working principle of slot antenna is presented.Through the method of coupling feed,the antenna covers the frequency range including 1.5-3.5GHz.This antenna adopts a novel slot to reduce the correlation of the antenna.And it has a good isolation which reachs(achieve)lower than-20 dB in its band.The second part,a compact monopole MIMO antenna is proposed which is based on the theories of the monopole antenna.It has dual-frequency which can applied to WLAN band.The antenna covers the frequency band including 2.4-2.5GHz,5.2-5.8GHz.This dual-frequency antenna adopts protrude branches and bent slots to improve antenna isolation.And the isolation of the antenna is lower than-20 dB in the double frequency range.It can meet the demands for mobile communications.Finally,we based on the principle of neutral line technique,a new MIMO antenna through the method of combining decoupling technique,branches and bent slots is proposed.This antenna unit adopts the coupled feed technology and matching circuit to broaden the bandwidth.Therefore,the antenna gets good impedance matching.The simulated results shows that the antenna has good isolation which is lower than-10 dB in its band.In order to verify the performance of the designed antenna,we tested the three MIMO antennas above,and the test results are similar to simulated results.The antennas can be suitable for modern miniaturized mobile terminal equipment.