The phenomenon of diffraction occurs when a wave encounters an obstacle in its path, as a result of which it changes its rectilinear propagation in space. Wave diffraction is described in the literature as: Fresnel diffraction (when the target is close to the receiver) and Fraunhofer diffraction (when the target is far from the receiver). A diffraction model from opaque objects in a near and far observation zone is presented and investigated. The diffraction pattern was interpreted using a Fourier transform. The relationships between the object parameters, the distance from the object to the receiver and the wavelength of the signal are studied. The obtained diffraction model can be used to study the phenomenon of direct signal propagation in bistatic radar systems as well as to detect and evaluate the parameters of moving objects.