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

CINRAD/SA RADIATION PATTERN AND FEASIBILITY FOR DUAL POLARIZATION UPGRADES

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。

Polarization measurements require higher radar performance. This study measures and analyzes firstly CIN- RAD 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 ZDR and LDR, 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.