Research And Design Of Wideband Wide Angle Scanning Phased Array Based On Vivaldi Antenna

Phased array antenna technology is widely used in military and civilian fields,and has always been the focus of the research of domestic and foreign experts and scholars.In recent years,with the rapid development of communication technology,phased array antennas develop towards broadband,wide angle and other high-performance direction.Wide-band and wide-angle scanning phased array has plenty of advantages,such as small gain fluctuation,wide beam scanning range and wide working frequency bandwidth.Therefore,researchers at home and abroad have spent a lot of time and experience studying how to make the phased array antenna have broadband and wide angle scanning characteristics.In this thesis,Vivaldi antenna is selected as array unit,and some wide-band and wide-angle scanning phased array antennas are studied and designed.Finally,one of the array antennas is fabricated and tested.The test results show that the antenna has excellent scanning and active VSWR characteristics in the working frequency band.The main contents of this paper are shown as follows:(1)Design and simulation of Vivaldi antenna array based on dielectric substrateFirstly,this thesis describes the basic theory of Vivaldi antenna,and proves theoretically that Vivaldi antennas have broadband characteristics.Then,a Vivaldi antenna element based on dielectric substrate is designed through the feeder and slot structure of the tapered exponential curve of the Vivaldi antenna.Next,the performance of the element in the infinite array environment is discussed through simulation using master-slave boundary conditions.In order to improve the scanning characteristics,parasitic notches and double FSS matching layers are introduced into the structure.Finally,three kinds of finite arrays composed of the designed array element are researched respectively: one-dimensional E-plane array,one-dimensional H-plane array and two-dimensional plane array.All of the arrays have excellent broadband and wide-angle scanning characteristics.The simulation results show that the arrays can achieve ±60° scanning,the active VSWR is less than 2.8,and the relative bandwidth is 40%.(2)Design and Simulation of all-metal Vivaldi antenna arraysIn this part,the application prospects of all-metal Vivaldi antenna array and dielectric Vivaldi antenna array are compared.Then,an all-metal Vivaldi antenna element is designed and we found that the mutual coupling effects between the elements decreases the radiation characteristics of the element in an infinite array environment.Therefore,in order to reduce the influence of mutual coupling effects,concave structure is introduced on both sides of the element.However,the concave structure has a drawback that the scan blindnesses phenomenon will occur in the working frequency band of the antenna array.In order to eliminate the blindness effects in the working frequency band,the electric field distribution corresponding to the blindnesses are observed by mode analysis,and the reasons of them are found and the scan blindnesses are moved out of the working frequency band.Finally,the design of infinite Vivaldi array element has excellent active VSWR characteristics and a 16×16 finite array is constructed according to the designed element.The simulation results show that the metal array can scan ±60° in the frequency band with 40% relative bandwidth,and the active VSWR is less than 2.5.(3)Manufacture and measurementAccording to the simulation model,we manufacture and measurement of a 16×16 all-metal array.The simulation results are compared with the measurement results.The results show that the measured pattern is basically consistent with the simulation results in the working frequency range,and the active VSWR is slightly larger than simulation.The above shows that the all-metal Vivaldi antenna array designed in this thesis has great broadband and wide-angle scanning characteristics.