Research And Design Of Microstrip Antenna Array For WLAN MIMO Applications

In order to improve the throughput, transmission distance and reliability of WLAN,MIMO technology is introduced by802.11n. But the realization of MIMO systems dependsnot only on the design of MIMO RF modules, also on the research of base station MIMOantenna which is responsible for uploading and downloading the electromagnetic wave, andits performance directly affects the overall performance of the entire system. Therefore, forthe popularization and applications of WLAN MIMO systems, two basic requirements ofits supporting antennas are proposed: First, meet the requirements for WLAN MIMOapplications, be able to take advantage of smaller space to achieve a better diversity gain andmultiplexing gain, and solve the resulting problem of the coupling between the antennas;Second, be low cost for large-scale promotion. So a three-channel microstrip antenna array forWLAN MIMO applications is designed and implemented.Firstly, for the subsequent design both the radiation characteristics of array antenna andthe mutual coupling between antennas are theoretically analyzed, and the requirements of theMIMO antennas design is also summed up. Then the double-layer microstrip patch antenna ofbetter impedance bandwidth is selected as a design prototype, and two dual-polarizedmicrostrip antenna elements and two four-element dual-polarized microstrip arrays aredesigned, respectively. Because the isolation of the±45°polarized microstrip antenna array istoo low to meet the design requirements, isolation improvement of the array is studied on thelayout of feeding network and the inverted feeding network, respectively. It notes that areasonable layout of feeding network and the appropriate introduction of the inverted feedingtechnology can improve the isolation performance of the array to a certain extent. Then athree-channel microstrip antenna array is finally designed by parallel combination of twodual-polarized microstrip array of vertical and horizontal polarization, then prototyped andmeasured. As a result, a microstrip antenna array of high gain, high isolation and low profilewhich meets the requirements for WLAN MIMO applications is obtained.Finally, the research work of this paper is summarized and the further study is discussed.