High Resistance Surface In Multi-beam Antenna

In recent years,with the continuous development of the antenna industry,the application of multi-beam antenna is not limited to the traditional military category,but also gradually to the high-precision real-time positioning,car collision avoidance radar and other new civilian category growth,antenna application scenarios are becoming more and more complex and diversified.The change of application range brings new requirements to the antenna.A large number of intelligent devices require the antenna to have a low profile structure,so as to facilitate the integration and miniaturization of the system.In this paper,the characteristics of broadband,low profile and low cost in multi-beam antenna system and multi-beam forming network are studied respectively for the array antenna and multi-beam forming network.The main research contents are as follows:Firstly,aiming at the extra cost and volume of the side wall port of Rotman lens,two improved methods of Rotman lens were proposed.A unit through the modulation surface cracks in the overthrow of wall load impedance,the alternatives to traditional design of virtual ports,make originally unwanted gap radiation energy is absorbed by the virtual port,the simulation data show that this method in the case of ensure lens broadband characteristics effectively cut the number of ports required lens,avoid the inside of the lens is invalid electromagnetic reflection and the insertion loss is reduced.Secondly,the side wall of Rotman lens was redesigned,and the waste clutter which had been filtered out was recycled and reused by inserting metal column,so that the insertion loss of Rotman lens was greatly reduced.Simulation data Rotman lens based on this method can achieve insertion loss <1dB in 25.5 ~ 28 GHz,but the broadband characteristics of the lens are sacrificed.Secondly,in order to overcome the disadvantages of high cost and large size of current 2d beamscan antenna,a 2d beamscan antenna with low profile,high gain and easy integration was designed by using the method of impedance modulated surface leakage wave antenna and traditional beamforming network Rotman lens.At the 10 GHz center frequency,the antenna beam covers an area of 10??? ?50? and-45? ?? ?45?.Compared with the N ?N phased array with similar beamforming characteristics,the system has the advantage of lower complexity due to the incorporation of frequency scanning characteristics in the scanning in two-dimensional space,so the cost is greatly reduced.Thirdly,in view of the shortcomings of the narrow bandwidth of the microstrip patch antenna,this paper proposes a method of loading an additional layer of impedance surface on top of the microstrip antenna,which successfully improves the bandwidth of the antenna.Expand the bandwidth to 50% while maintaining the advantages of small size,simple design,easy manufacture and integration,and low cost.The effects of impedance patches of different shapes on antenna performance were compared.The improved patch antenna can be matched with a broadband beamforming network such as Rotman lens,and the beam scanning capability of the array is verified by simulation.