Phase mathematical modelling for corner reflectors in remote sensing synthetic aperture radar applications

In microwave remote sensing there is a well assessed use of corner reflectors (CR) for the calibration of synthetic aperture radar images. The recently proposed utilisation of interferometric procedures raises some questions about the phase behaviour of the CR radar cross section (RCS). Scarce, if no information is available in the literature. Furthermore a future, expected, use of CR in fixed positions on permanent test sites extends the question to the off-boresight RCS cuts. A physical optics model, suitable to provide detailed informations concerning the electromagnetic field backscattered by trihedral corner reflectors, is presented. Closed form solutions have been obtained for various geometries. They take into account the lighting of each face by the direct rays, the singly and the doubly reflected ones. As a consequence, a very accurate amplitude and phase description is obtained. Such results can be specifically applied to the considered problem