Abstract: The dihedral reflector with wing and fuselage joint is a very strong electromagnetic scattering source in a wide angular region. The prediction of the electromagnetic scattering and radar cross section from this construction, however, is a complicated theoretical problem, because one of the dihedral surfaces is curved. In this paper, the problem is analysed and calculated by the method of complex ray expansion combined with geometrical theory of diffraction, respectively dealing with the specular multi-reflections and the edge diffractions. The influence of the geometrical parameters of the construction, such as the angle between wing and fuselage, the radius of airframe, on the radar cross section of target is evaluated numerically. The obtained results show that the presente'd method is an effective approach to the radar cross section prediction, and the scattering contribution from the wing-fuselage dihedral can be reduced substantially by the computer optimization of geometrical construction.

Key words: radar cross section, complex ray theory, wave expansion