| As an array type with fast beam scanning function,phased array antenna has become an important research hotspot in the field of antenna research in recent years.Especially in the radar system,the phased array antenna overcomes the disadvantages of mechanical scanning in terms of slow scanning speed and low data transmission rate.It can use the phase-shifting network to control the unit excitation and amplitude to realize the rapid switching of the beam and achieve the coverage of the beam at a specific angle.Therefore,phased array antenna is officially used in communication systems such as mobile communication,radar system,satellite communication,airborne shipborne and so on.However,there are many technical bottlenecks in phased array antenna at present.On the one hand,due to the mutual coupling effect between array elements,with the increase of scanning angle,the active reflection coefficient of the array increases,and total reflection will occur at some angles,resulting in scanning blind spots;On the other hand,the scanning angle of the phased array itself is limited within ± 50 °.The rapid development of radar system puts forward higher performance requirements for phased array antenna,which not only requires its wide angle scanning performance,but also puts forward higher requirements for the working bandwidth of the antenna.Therefore,it is a challenging research topic for phased array antenna to have the performance of broadband and wide viewing angle two-dimensional scanning at the same time,and pattern reconfigurable antenna has demonstrated the ability of two-dimensional broadband and wide viewing angle scanning.On this basis,based on pattern reconfiguration technology,two broadband and wide beam antenna elements are proposed and applied to planar phased array antenna.Firstly,this paper describes the research background of phased array antenna and the research status and development trend of broadband and wide viewing angle scanning phased array,and leads to the relevant theoretical basis used in this paper,including the basic theory of microwave switch,the basic theory of Vivaldi antenna,the pattern product theorem and the basic theory of phased array.Then,based on broadband Vivaldi slot antenna and broadband artificial magnetic conductor(AMC)structure,and using pattern reconfigurable technology,a windmill pattern reconfigurable antenna unit based on AMC reflector is proposed,and a reconfigurable feed network and DC bias circuit with pin diode as microwave switch are designed.Then,based on this element,the scanning characteristics of one-dimensional 10 element uniform linear array and two-dimensional 64 element plane array are analyzed.The simulation results show that the two array antennas have the performance of one-dimensional beam scanning in the range of ± 64 ° in the working bandwidth of 4.5 ～ 6 GHz(active VSWR < 3)and twodimensional beam scanning in the range of ± 60 ° in the working bandwidth of 5.4 ～ 6.1 GHz.Further,a research idea combining reconfigurable technology and wide beam radiation for wide-angle scanning in different directions is proposed.Firstly,the joint wide beam of dipole element antenna on YOZ plane is realized by using pattern reconfigurable technology.At the same time,the dipole antenna is placed parallel above AMC structure,so that it also obtains wide-band beam characteristics on xoz plane,The dipole element formed by the combination of the two has the characteristics of wide beam in two orthogonal planes of xoz and YOZ.Then,based on the antenna unit,5 × 5 planar array antenna.The simulation results show that the array can realize beam scanning in the range of ± 60 ° of E-plane and H-plane in the frequency band of 7.1 ～ 8.2 GHz(active VSWR < 3),and has good two-dimensional broadband and wide viewing angle scanning performance.Finally,the paper summarizes the research content of this paper,and looks forward to the future research direction. |
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