正交偶极子的极化特性分析

双极化相控阵天线的极化特性及其对目标极化散射矩阵测量的影响,将决定相控阵体制雷达获取目标极化信息的精度和能力,是相控阵雷达极化技术的基础。以正交偶极子为阵元模型,分析了双极化阵列天线的空域极化特性及其对雷达目标极化散射矩阵测量的影响。由于两阵元辐射电场在偏离视轴方向的非正交性,不可避免地会引起两天线交叉极化之间的相互干扰。根据传统交叉极化评价指标的定义,分析了正交偶极子天线的交叉极化特性,并从目标极化特性测量性能的角度,定义了双极化雷达系统的交叉极化隔离度,将其表示为极化测量系数矩阵条件数的形式,以衡量全极化相控阵雷达天线的交叉极化特性。

Polarization characteristics analysis of crossed dipoles

The spatial polarization characteristics of dual-polarized arrays and its influence on the polarization scattering matrix measurement of target are analyzed in this paper by using crossed dipoles as elements.Because of the nonorthogonality of the radiated electric field at off-broadside,it is inevitable to cause cross-polarization interference between crossed dipoles.The cross-polarization characteristics of crossed dipoles are analyzed according the traditional evaluation definition.Furthermore,the cross-polarization isolation(XPI)of dual polarized radar system is defined in the respect of target polarization scattering matrix measurement,which is denoted by the polarization measurement formula and evaluate the stability of polarization measurement methods.