Research On Ultra-wide Bandwidth Angular Scanning Array Of Planar Structure

With the development of communication and detection technologies,system has gradually developed in the direction of high efficiency,large capacity,and low multipath effects.Ultra-wideband technology has received great attention.The antenna array combines the transceiver components and the control and processing circuits to form a phased array for flexible beam control.Broadband wide-angle scanning phased array antenna is an important part of a multifunctional radio frequency system,which can greatly reduce the number of antennas required by the system,weight,and space occupied by the system,in space-borne,ball-borne,airborne and shipborne platforms.The application has important significance and broad application prospects.This dissertation studies a planar ultra-wideband wide-angle scanning tightly coupled dual-polarized array antenna.The bandwidth can cover S-band,C-band,X-band,and Ku-band.The main contents are as follows:First,the ultra-wideband principle and wide-angle scanning principle of TCDA antenna are discussed.Based on the equivalent circuit model of the tightly dipole array,the effect of the coupling between the dipoles,the height of the dipoles from the floor,and the wide-angle matching layer on the impedance of the array is simulated and analyzed.Second,for the TCDA array using the unbalanced feeding structure,the common-mode resonance caused by the asymmetric current is analyzed,and a shorted metal plate is added below the dipole to shift the common-mode resonance frequency down out of the bandwidth.Besides,digging periodical air holes in WAIM can effectively put off the scanning blindness.Third,a multi-layer dielectric structure of broadband wide-angle scanning dual-polarized TCDA is designed,and metal sheets are added at the feeder to optimize impedance matching and expand the low-frequency bandwidth,and some improved designs are proposed for WAIM.The array can achieve a 5:1 bandwidth with±60°scanning in E-plane and±45°scanning in H-plane with active VSWR<3,and the profile height is 0.46.A 19×21 TCDA was processed,and the finite array simulation and experimental research were conducted for the test.Finally,combined with the simulation of the semi-infinite array and the small finite array,the test of the array antenna is analyzed.The simulation analysis of the coupling between the elements of the tightly coupled array,the characteristics of the active S-parameters,and the pattern of the central element.For the 5×5 finite array in the large array,the transmission coefficient between the center element and other elements is tested,and the transmission coefficient amplitude is in good agreement with the corresponding simulation results.Using the active element pattern measurement method,the far-field radiation pattern of the 5×5 array is tested.The measured data of the pattern have good consistency with the simulation.The study of simulation and measurement has verified the correctness of the design and predicted that large arrays can achieve good bandwidth and pattern performance.The tightly coupled antenna designed in this paper can expand the low-frequency bandwidth,and analyze common-mode resonance and scanning blindness.Finally,an easy-to-process,low-cost,ultra-wideband tightly coupled wide-angle scanning dual-polarized antenna is designed.