Evaluation of the field backscattered by loaded trihedral corner reflectors

In this paper the problem of the analytical determination of the field backscattered by loaded trihedral corner reflectors is tackled and solved. Triangular, square and square-based trihedrons are considered and the loading of their internal faces, which can be obtained with a dielectric layer placed upon a perfectly conducting plate, is here treated as a surface impedance boundary condition, a model whose validity is well assessed in literature. The proposed method employs the Geometrical Optics both to evaluate the illuminating electric field related to the direct, singly and doubly reflected rays incident on each corner face and to determine the shape of the corresponding illuminated patches. At last, it uses a generalization of the Physical Optics to loaded surfaces for the evaluation of the backscattered field. As expected, this last is strongly affected by the values of loading parameters and this allows to control the backscattering characteristics. Moreover, the solution is uniform with respect to the loading impedance, i.e., it leads to that for the perfectly conducting case when the surface impedance approaches zero.