ONE-DIMENSIONAL AND 2-DIMENSIONAL NEAR-FI ELD FAR-FIELD TRANSFORMATION APPLIED TO RCS MEASUREMENTS

In high frequency the Res measurement of large target must be done at important distances, so the distance Of measurement (Fraunhofer's dist ance) R is given by R greater than or equal to 2d(2)/lambda where d is the tranversal length of the target and lambda the radiation waveleng th. In this paper we present a method for target that are large relati ve to the curvature of the spherical wavefront and the curvature of th e cylindrical wavefront. A two-dimensional analytical algorithm transf orms the spherical wave (nearfield) measurement into the desired plane wave (far-field) and a one-dimensionnal analytical algorithm transfor ms the cylindrical wave (near-field) measurement into the desired plan e wave (far-field). We present some results on simulations and measure ments. A comparison of one-dimensional and two-dimensional methods dem onstrates the efficiency of the two dimensional methods.