近场条件下散射计的绝对定标

在推导散射计定标公式的基础上，本文分析了远区条件对于雷达散射计绝对定标的意义，通过引入有效雷达散射截面的概念，将入射波前球面弯曲和波束限制引超照射不均匀以及接收天线增益的变化等效为目标雷达散射截面的变化。

Absolute Calibration of Scatterometers in Near Field Region

In this paper,procedure of the absolute calibration of radar scatterometer is presented. Effects of the far field criterion for the calibration are analyzed. After converting the effect of curvature of spherical wavefront and the amplitude and phase nonuniformity of the incident field to the variation of the radar cross section, the concept of effective radar cross section (ERCS) is introduced to unify the calibration formula for near field region and far field region measurement, Using the new formula,a practical near field region absolute calibration scheme is proposed. Absolute calibrations of four scatterometers of S,C,X and Ku band show the validity of the given method.