| Antenna arrays with excellent scanning performance are widely used in communication,radar,detection and other fields because of their superior performance.Its working principle is to realize spatial beam scanning by adjusting the excitation phase of each element in the array.Compared with the traditional mechanical scanning method,the phased antenna has higher flexibility in scanning,and the beam switching speed is more agile and fast.Therefore,it has a wide range of applications in military electronic countermeasure field or civil meteorological navigation.The wide application prospect and superior performance make the research and design of phased antenna have important research value and significance.In this paper,the performance of phased array antenna is studied in terms of bandwidth and scanning Angle,and an array antenna structure with wide-band and large-angle scanning performance is designed.The main contents are summarized as follows.Firstly,the research background of the array antenna is introduced.The common design ideas and research methods of the wide-band large-angle scanning phased array antenna are analyzed,and the array characteristic theory of the phased array antenna is given.Then the basic design indexes of the array antenna are analyzed.At the same time,the product theorem of array pattern without mutual coupling is introduced through formula derivation,and the basic conditions of inhibiting gate flap in array pattern under one-dimensional array and two-dimensional array environment are deduced,which provides theoretical reference for the whole array arrangement and simulation design.Then,the mechanism of mutual coupling phenomenon and mutual coupling effect are introduced.The influence of mutual coupling on the large-angle matching and scanning performance of the array is analyzed,so as to provide theoretical basis and thinking reference for the design of wide-band large-angle scanning array.Secondly,the array design based on the back cavity element model and the array design based on the butterfly slit dipole element structure are introduced.The models and structural parameters of two kinds of array designs are given.The array spacing is set within half wavelength.The performance parameters of the two kinds of arrays in largeangle scanning are analyzed.The optimal design makes the arrays have good performance index when scanning to large angles on a wide operating frequency band.When the arrays with two polarization modes designed based on the two types of structures scanning to large angles on a wide operating frequency band of X-band,the standing wave ratio is less than 3.The two single-polarization arrays can scan up to 60° in the 3.6GHz and 3GHz frequency bands,respectively,and the two dual-polarization array structures can scan up to 60° and 30° in the two scanning planes in the 1.5GHz and 2.5GHz frequency bands,respectively.Finally,the working principle of the designed array structure is analyzed by performance parameter simulation.The structure of the array element is based on the back cavity antenna model and the butterfly slot dipole antenna model respectively.The two kinds of array structures have different working principles to realize the large-angle scanning performance on a wide operating frequency band.The back cavity antenna model is based on the mutual coupling between the array elements and the interaction between the element cavity,the feed microstrip and the parasitic microstrip structure,and the upper dielectric matching layer can improve the large-angle matching performance.Butterfly slit dipole structure uses its own slit dipole structure characteristics and metal floor reflection structure to achieve design performance.Two types of structure design can provide reference for this kind of design. |
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