| Wideband phased array radar is a new radar which is making important applications in many aspects such like target imaging、multi-target tracking、measuring the position、anti-missile radar, and it will play an important role in the future of military and civilian fields.The applications of wideband phased array in UAV research is the hot spot in many countries. For the requirements of X-band wideband phased array antenna, the broadband Vivaldi antenna unit is designed and the analyzed various characteristics of the antenna structure are anysised. According to the the design of the antenna, the array scheme of airborne antenna is researched. The main work contents of this paper are as below.Vivaldi antenna on the related theories were studied, which proved that the Vivaldi antennas meet scaling theory. The current distribution characteristic of its groove line were researched. After collated Vivaldi antenna design methods, the characteristics of the various structures and the design methods were studied. Appliying the Chebyshev multi-section impedance transformer, the Vivaldi antenna impedance matching was designed. According to the specified design range for each antenna parameters, the Vivaldi antenna was preliminary designed and the antenna model was obtained. After analysised the effects of various parameters on the antenna, antenna performance was optimized and a fold structure is applied to the antenna.Then the final antenna model and its antenna size were obtained. According to the simulation results, the optimized bandwidth Vivaldi antenna covers a good X-band; return loss is less than-12 d B,VSWR is less than 1.8 in X- band, the antenna gain is greater than 7d B, the beam width is greater than 50 °. Finally, compared with the relevant results, the feasibility of the antenna was verified.After studying the designed X-band Vivaldi antenna elements, the array antenna integrated approach was studied. Contrasted pattern characteristic of Dolph-Chebyshev consolidation, Taylor comprehensive method was chosen to design the airborne phased array design. The previous designed Vivaldi antenna unit was applied for airborne applications lineup. The antenna array was arranged by using Comprehensive Taylor with 16 antenna elements and then the antenna array was layout on the belly of aircraft with 5 Taylor linear array of cloth into planar array antenna arrangement method. The simulation results show that the lineup method has a good performance and its vicelobe level SLL at-30 d B or so, the antenna gain is greater than 18 d B, scan width of ± 30°within the X-band which are meet to the needs of phased characteristic array. |
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