The Hybrid GRE-FDTD Method for Calculating the Electromagnetic Scattering of Cavities

The electromagnetic scattering calculation of the inlets of aircrafts is one of the difficult problems to analytically predict the RCS of aircrafts. Compared with the wavelength of centimeter wave radar, the inlet of a aircraft is an electrically large object. Furthermore, there are complex structures such as the engine fans at the end of the inlets. It's hard to deal with such problems if we use high frequency method only. The hybrid GRE-FDTD method is introduced in this paper. The GRE method is used to treat the front part of the inlet. which is slowly varied. The FDTD method is used to treat the end part of the inlet, where the complex structure is involved. The results are compared with that obtained by Modal-MoM hybrid method. They agreed quite well.