Use of point contributors model for a radar target taking into account mutual coupling by double reflection

In a previous letter we showed that the electromagnetic mutual coupling between two diffractive bodies can considerably modify the radar cross-section diagram of these bodies. We commented on the preponderance of mutual coupling by double reflection and established a new formula for the RCS of a system of two spheres, giving excellent results in practice. In this letter, we shall propose a generalisation of the previously established formulas, and shall give a law of composition for the contributions fit for use with the complex models of specular point contributors. In the second Section we shall show how it is possible to replace a model of isotropic point contributors with couplings by a model without coupling by adding imaginary isotropic points.