Design Of Low-Profile Wideband Wide-Angle Scanning Array

Due to the rapid and flexible beam scanning,phased array is widely applied to radar detection satellite communication,and other fields.Meanwhile,the development of information technology has put forward higher requirements for the multi-function and integration of electronic systems.Therefore phased array with the properties of low profile,broadband,and wide-angle scanning is urgently required.The emerging tightly coupled array takes advantage of the coupling between adjacent elements so that the array can realize ultra-wideband while maintaining wide-angle scanning and low profile at the same time,which opens a new way for the design of phased array with a low profile,broadband,and wide-angle scanning.To the above requirements,the array with a low profile,broadband,and wide-angle scanning based on the tightly coupled array is studied and designed in this thesis.The main contents of this thesis are as follows:1.Design of the planar low-profile wideband wide-angle scanning array.To solve the contradiction that the vertical tightly coupled array is wideband but hard to integrate,while the planar tightly coupled array is low-profile but narrow-band,a full-planar array with a profile of 0.09λ_L(λ_L is the free space wavelength at the lowest frequency)is designed,which has the bandwidth of 5:1(3-15GHz)and the beam scanning range of±45°.The structures of unbalanced feed and dipole printed horizontally are employed to reduce the profile and make the proposed array full-planar.To keep the feed balanced,capacitive via is used to suppress the common-mode resonances,and ribs are used to enhance the coupling between feed via and grounded via.In addition,multi-layer dielectric superstrates are used as the wide angle impedance matching layers to realize wide-angle scanning.The substrates and superstrates are perforated with air holes,to avoid the impact caused by the surface wave.The measured results of the prototype verify the design.2.Design of the linear low-profile wideband wide-angle scanning array.For application in narrow and long areas,a linear phased array with a profile of 0.13λ_L is designed,which has a bandwidth of 3.1:1(3.8-11.6GHz)and a beam scanning range of±60°.To compensate for the missing boundary conditions when the tightly coupled array is transformed from two-dimensional to one-dimensional,vertical metal walls are loaded on both sides of the proposed array.The metal walls and ground plane are notched to improve the impedance matching.The measured results of the proposed 1×16 linear array prototype verify the designed linear array.In addition,based on this design,a linear conform phased array with a bandwidth of 4-12GHz and a beam scanning range of±45°is designed.3.Design of the large-spacing low-profile wideband wide-angle scanning array.To reduce the amount of T/R components and the cost of the array,two phased arrays with large spacing,low profile,broadband,and wide-angle scanning based on the triangular lattice are designed,which can reduce the costs by about 13.4%.Firstly,by using an unbalanced feed,a phased array arranged on a triangular lattice with element spacing of 0.52λ_H×0.64λ_H(λ_H is the free space wavelength at the highest frequency)and a profile of 0.16λ_L is proposed,which has a bandwidth of 5-12GHz.The common-mode resonances caused by unbalanced feed are suppressed by loading grounded via and capacitive via,and the scanning performance is improved by the loading of metal walls.The proposed array can scan up to±45°in 5-12GHz and±60°in 8-12GHz for H-plane scanning.Then,by using a balanced feed,a phased array arranged on the triangular lattice with the element spacing of 0.525λ_H×0.605λ_H and the profile of 0.143λ_L is proposed.The common-mode resonance for E-plane scanning is suppressed by metal walls.Finally,the proposed array can achieve a bandwidth of7.4-12.6GHz and can scan up to±45°in E-plane and H-plane.