An improved physical optics model for the evaluation of the field backscattered by triangular trihedral corner reflectors

An improved physical optics (IPO) model for the evaluation of the field backscattered by triangularly shaped trihedral corner reflectors, with perfectly conducting faces, is developed. It allows a significant improvement to the basic PO model by using the geometrical theory of diffraction (GTD) instead of geometrical optics (GO) to describe the interaction between the corner faces. In fact, besides illumination by direct, singly and doubly reflected rays, illumination by rays simply diffracted from the corner edges and illumination by those diffracted and subsequently reflected is taken into account when determining the PO current distribution on each corner face. The comparison with experimental results obtained by the authors in an anechoic chamber is very good, thus confirming that, when the field backscattered by composite structures is considered, far better results are obtained by using the GTD instead of the GO to determine the PO current distribution