A fast algorithm for the analysis of scattering by elongated cavities

Electromagnetic scattering from elongated, arbitrarily shaped, open-ended cavities (OEC) has been studied extensively over the years. In this paper, we introduce the fast encapsulating domain decomposition (EDD) scheme for the analysis of radar cross section (RCS) of such OEC. The EDD advantages stem from a domain decomposition along the elongated dimension, followed by a spectral representation of the fields in each segment, whereby the field is naturally separated into in- and out-going waves. This diagonalizes the translation between the cross sections, thus reducing the per segment computational complexity from O((N A) 3) to O(N W (N A) 2), where N A and N W are the number of aperture and wall unknowns per segment, satisfying N W << N A as the segmentation is constructed to be smaller than the cross section. The results of the EDD are demonstrated on an S-shaped elongated open-ended cavity.