Abstract: The low observable structure is a type of the structures which consist of skin and various internal materials, and have low radar cross section (RCS) together with the considerations of their stress and other requirements. Two kinds of the low observable wing structures are designed for a low observable unmaned air vehicle. But numerical simulation of electromagnetic scattering for such wing structures is a challenging problem because the wing structures consist of different materials having different eletric and magnetic properties. The paper proposes the applications of the finite difference-time domain (FD-TD) method to the numerical simulation of electromagnetic scattering for such wing structures, and presents the simulation results of electromagnetic scattering characteristics of those kinds of the low observable wing structures. The results indicate that the RCS values of those two types of wing structures are reduced substantially compared to conventional wings, as well as the graphite-embeded foamed polystyrenes have major contribution on the RCS reduction of two wing structures. The conclusions can be used as a guidance for further reducing RCS value of the low observable structure using optimization methods.

Key words: low observable structure, radar cross section, aircraft structure