Variational estimation of radar cross-sections

The authors describe the application of variational techniques to the electromagnetic scattering problem. It is shown that these techniques can deal effectively with distorted structures and the case of orthogonal and nonorthogonal distorted dihedrals is considered in some detail. The importance of plate distortion in dihedrals is demonstrated. When the plates are distorted in a convex manner, the reduction in the wide-angle RCS gained by opening up the dihedral can be compromised. If the plates are distorted in a concave manner, however, the distortion further aids the opening up of the dihedral in reducing the wide-angle RCS return. These cases demonstrate the importance of considering both the size and type of distortion in RCS calculations which are to be used to investigate shaping measures for RCS control. Conclusions drawn from calculations which use idealised flat-plate structures are likely to be misleading when applied to real-world distorted structures