圆口径正馈抛物面天线的近场分析  

On near field of circular aperture normal feed paraboloidal antenna

作　　者：高初[1] 李刚[1] 

机构地区：[1]中国电子科技集团公司第38研究所,安徽合肥230031

出　　处：《电波科学学报》2009年第3期467-470,共4页Chinese Journal of Radio Science

摘　　要：分析了圆口径正馈抛物面天线的近场。采用口径场绕射积分求取了天线的近场及远场方向图,绘制了波束宽度、方向性和最大副瓣电平三个关键参数随场点距离的关系曲线。通过与物理光学法的计算结果对比,验证了该方法的正确性。仿真结果是:随场点距离的减小,波束宽度展宽,方向性减小,最大副瓣电平在一定范围内波动。场点在D2/λ外,远场近似的波束宽度误差小于1%;在0.5D2/λ外,远场近似的波束宽度误差小于10%;在0.5D2/λ内,不能采用远场近似。Near field of a circular aperture normal feed paraboloidal antenna is analyzed. Radiation patterns of both near field and far field are calculated by aperture field diffraction integral method. Three key parameters, namely beamwidth, directivity and maximum sidelobe level, are drawn versus the distance between field points and the center of aperture. The correctness of the results is validated by the comparison with the results obtained by physical optics. The simulation results show beamwidth broadening, directivity decreasing and maximum sidelobe level fluctuating within a typical range with the decreasing distance. In conclusion, the far field approach has a beamwidth error less than 1% beyond a distance of D^2/λ and a beamwidth error less than 10% beyond a distance of 0.5 D^2/λ . And the far field approach is not applicable when the distance is less than 0.5 D^2/λ.

关 键 词：抛物面天线 近场 波束宽度 方向性 最大副瓣电平 

分 类 号：TN011[电子电信—物理电子学]