Combination of PO/SBR and the finite element method for scattering from a large PEC target with a small cavity

High frequency methods such as physical optics (PO) and shooting and bouncing rays (SBR) are very effective in calculating the scattering from large perfectly electrically conducting (PEC) bodies. However, pure high-frequency methods cannot deal with small structures such as small cavities mounted on a large PEC body. Under certain circumstances, these small structures may have significant contributions to the scattered field. A promising technique to overcome this shortcoming is to incorporate low frequency methods like the method of moments (MoM) or the finite element method (FEM) to the high frequency methods. The present authors provide such an approach to combine PO/SBR and the FEM to compute the scattering from a large PEC body with a small cavity.