Analysis Of The Mutual Coupling Effects Between The Base Station Antennas With Sharing Site

With the fast evolution of the mobile communication technology from the second generation(2G)to the fifth generation(5G),the mobile communication operators choose to co-construct and share the base stations,which in turn leads to more and more antennas on the same tower.Then,the mutual coupling between these antennas will occur.To minimize the coupling effect,proper configuration of the antennas should be well studied.In this thesis,the mutual coupling between the antennas mounted on the same tower is deeply explored,and the coupling coefficient is estimated,which should be helpful for the co-construction and sharing of the base stations.In this thesis,several configurations of the base station antennas are analyzed through the method of moment.The main innovations of this paper are as follows:(1)Radiation patterns of the base station antennas are analyzed based on the method of moment at 1800 MHz,1940MHz,2100 MHz and 2600 MHz,respectively,where RWG basis functions are used.Compared with the commercial base station antennas,the simulated results,such as the radiation patterns,maximum gains,3dB horizontal beam widths and front-to-back ratios,are well consistent the measured results.(2)The estimation theory of horizontal spatial isolation for base station antennas is compared with the Frith Transmission formula,With the introducing of the error approach function,the far-field conditions is proved to be d ? 13?,which makes these isolation estimation theories suitable for practical engineering applications.(3)The isolations between the base station antennas for various configuration are calculated and compared with the measured results.It proves that the mutual coupling between the adjacent transmitting antennas will lead to the distortion of the horizontal radiation pattern,while for the vertical radiation pattern it seems to have little impact.The isolation for the configuration of vertical distribution or hybrid distribution is better.Through selecting different polarization modes,using frequency band isolation,and setting the electric down-tilt angle,the performance on the isolation can be further improved.(4)The widely accepted “concentric circles mode" for the multi-platform and multi-system environment is analyzed.For such co-construction and sharing base stations,the maximum SNR deterioration of two sets of dual-platform antenna systems and three-platform antenna systems are detailed analyzed,where the platform radius,vertical distance and arrangement order are considered as independent variables.The conclusion provides the helpful reference for the co-construction and sharing base stations.