CINRAD/SA雷达天线的辐射特性分析及其支持双线偏振升级的可行性研究

文中较全面地测量了CINRAD/SA天线的水平和垂直共极化和交叉极化辐射数据,分析了CINRAD/SA天线的主瓣、旁瓣、交叉极化电平等天线辐射特性,并与美国WSR-88D雷达双线偏振改造前后的辐射特性进行了比较,提出了CINRAD/SA双线偏振升级后降低旁瓣电平的几个措施,讨论了同时发射和同时接收双线偏振收发体制下,由天线水平和垂直偏振辐射不均衡产生的ZDR误差和偏振交叉耦合项ICPR值。结果表明:(1)CINRAD/SA雷达天线具有较好的辐射性能,主瓣波束较均匀,旁瓣和交叉极化电平优于设计指标值;(2)CINRAD/SA的天线辐射性能接近于WSR-88D,CINRAD/SA天线经调整后旁瓣电平应可以满足双线偏振升级要求;(3)ZDR误差和ICPR值足够小且在统计误差范围内,能满足CINRAD/SA双线偏振改造对测量精度的要求;(4)现用天线的辐射性能可支持CINRAD/SA双线偏振升级。文中还讨论了天线馈源支撑杆对辐射特性的影响,建议CI NRAD/SA天线的偏振改造仍采用三杆支撑方式,由此产生的水平和垂直偏振与高旁瓣脊间的不匹配,可计入系统误差,通过定标予以消除。关键词:CI NRAD/SA,雷达天线,辐射特性,双线偏振。

CINRAD/SA RADIATION PATTERN AND FEASIBILITY FOR DUAL POLARIZATION UPGRADES

Polarization measurements require higher radar performance.This study measures and analyzes firstly CINRAD co-polar and cross-polar antenna radiation patterns,and evaluates synthetically CINRAD/SA radiation patterns.Results of the mainlobe,sidelobe,and cross-polar level analyses show that the CINRAD/SA antenna has good performances,the mainlobe radiation is basically symmetry,and the sidelobe and cross-polar level are better than the design targets,but the vertical mainlobe is not as good as the horizontal mainlobe.In comparison with the influence on the sidelobe of NEXT WSR-88D polarimetric upgrades,the CINRAD/SA radiation patterns are close to the NEXRAD WSR-88D's.The CINRAD/SA sidelobe level after upgrades will be about-25 dB below target value-27 dB,so we suggest some enhancement measures to decrease the sidelobe by reducing the obstruct of support spars.After adopting such adjustment,we ensure that the current antenna of CINRAD/SA is feasible for polarimetric upgrades.In the context of the radiation pattern measurements of the antenna characteristic,we examined the errors of Z_(DR) and L_(DR),their values are still within the range of the statistical errors of polarimetric measurements.We ensure that the CINRAD/SA antenna could be used to polarization alteration.