Feed Networks For Multi-beam Antenna Arrays

In recent years,with the rapid development of wireless communication technology,the popularity of 4G networks,the advent of Internet of Things,People require bigger and faster on the communication system of communication capacity and communication rate.As an important part of mobile communications,base station antennas have also been put forward more different demands,the traditional base station antenna with a port corresponding to a wide beam covering 120°sector program has been unable to meet the requirements of transmission rate and system capacity,In order to solve the problems we divide the original 120°sector into several small sectors with a base station antenna having a plurality of directional beams,and the access points of the different small sectors can communicate with each other at the same frequency without interfering.So we have to use multi-beam array antenna technology.Multi-beam coverage which replaces the traditional station antennas by using multiple sub-beams to combine the individual sectors has the advantages of wide coverage,high gain and low cost.In order to meet these requirements,the design of multi-beam feed-network is becoming more and more important.Based on research projects and the communications technology of the beam forming network,this paper demonstrates these research work:1.For different scenarios in the mobile communication,a beam-forming networks with different number of the orthogonal beam number.Based on the Givens matrix transformation,this paper design a method of generating odd orthogonal beam network topology and designs the orthogonal beam feed network topology of N=5 in the specific application scenarios by means of circuit simulation,verifying the correctness of the topology with ADS simulation software.2.Design different components which can generate N=5 orthogonal beam feed network.The multi-beam feed network designed in this paper,is applied to the 5G mobile communication system.We set the 5G antenna in the millimeter-wave band,due to the lack of spectrum resources and low-frequency spectrum resources have been fully utilized,and at this stage,the two main center frequencies are 28 GHz and 38 GHz,The design is based on the center frequency of 28 GHz in this paper,so the network device is designed using a dielectric integrated waveguide(SIW)technique to ensure low insertion loss in the high frequency band.The components to be designed include directional coupler of 180°and phase shifters and cross couplers.3.The simulation verifies the conversion forms of several different dielectric waveguides to coaxial transitions,including dielectric waveguide to microstrip coaxial,dielectric waveguide to metal waveguide,dielectric waveguide to coaxial directly.And finally determine the way that the entire orthogonal network topology is fed using a dielectric waveguide directly to the coaxial mode.4.A slotted patch antenna with slotted coupling is designed for the orthogonal beam feed network and a 1×5 array antenna is formed.The antenna is loaded onto an orthogonal beam feed network of N=5 to form a five beam of the slot antenna array.