Physical optics analysis of the field backscattered by a depolarising trihedral corner reflector

Abstract

A physical optics (PO) model is developed to analyse the backscattering properties of an anisotropically loaded trihedral corner reflector, which can be obtained from the conventional triangular one by corrugating one of its interior faces. In such a way it can present a dihedral-like polarisation response over a wide angular range in both azimuth and elevation, thus making it particularly attractive for use in polarimetric radar systems as a location marker for radar navigation, and as a ground reference target in remote sensing applications. In fact, it can be designed to return elliptically or circularly polarised waves with the same handedness as the incident ones, and to rotate the polarisation of linearly polarised incident waves by 90°. The proposed model treats the corrugated surface as an anisotropic impedance boundary condition (IBC). Moreover, it evaluates in explicit form both the illuminating electric field related to the direct, singly and doubly reflected rays incident on each corner face and the shape of the corresponding illuminated patches. This allows a closed form evaluation of the related PO backscattering integrals, which produces a very fast computer code also suitable for non-powerful computers.