Research On Multi-beam Antenna Based On Rotman Lens

The multi-beam technology has been widely used in the navigation communications,detection and other fields as it can greatly improve the coverage of radiation power and channel capacity for maximizing the use of spectrum resources.With the simplification of the antenna,lightweight and integrated requirements are getting higher and higher,the application of traditional waveguide is limited.Meanwhile,the traditional planar circuit structure is also difficult to use because of its large loss when applied to the millimeter waves and terahertz bands.The proposed Substrate Integrated Waveguide(SIW)addresses these difficulties since they combines the advantages of both conventional waveguides and planar circuits.Moreover,the antenna requires lower antenna sidelobe in modern radar and high-performance communication system.Therefore,this paper mainly studies the Rodman lens multi-beam antenna based on microstrip and SIW,and discusses its low sidelobe performance.Firstly,the article studied a classic beamforming network-Rotman lens.The basic concepts and theories are expounded.The design method of the Rotman lens profile is analyzed by geometrical optics method,and the modeling process and simulation results are given.And then the Rotman lens network and the printed Yagi antenna array is connected by the phase shifter which is composed of the microstrip delay line,thus two different microstrip-type multi-beam antenna arrays are achieved with different beams and different array.The design and simulation results of these two kinds of antennas are given,and the beamlet cancellation technique is used to realize the reduction of the sidelobe level of the Rotman lens multi-beam antenna with a large number of beam ports.Secondly,the basic principle of SIW and its analysis method are studied.At the same time,in order to realize the transition of microstrip and SIW,the transition structure of a cone converter is studied.In order to realize the design of the integrated waveguide slot array of low sidelobes,the theoretical analysis of two kinds of amplitude distributions and Elliott iterative methods are given.Based on this theory,the low sidelobe substrate integrated waveguide is finished design.The principle and method of the integrated waveguide phase shifter of three different structures are studied,and the concrete structure and simulation results of the phase shifter with the phase shift of 60 are given.Then,a substrate integrated waveguide self-compensating phase shifter is designed,which is used in the Rotman lens multi-beam antenna.The phase shifter is integrated with the microstrip Rotman lens network and ten-elements Yagi antenna array.A multi-beam antenna with a microstrip-SIW hybrid structure is designed and the simulation is provided.Finally,a 10×8 substrate integrated waveguide slot antenna array with low sidelobe is designed and integrated with the microstrip Rotman network and the microstrip delay line phase shifter in the same media board,which constitutes another form of the microstrip-SIW hybrid structure of the multi-beam antenna.Its low sidelobe performance is analyzed.