Fast Computation of the EM Effect of Small Defects on Large Objects

Aircraft and vehicles often have small surface imperfections like protruding rivets or tiny holes. Despite being smaller than the wavelength of the impinging waves, these imperfections can significantly affect the electromagnetic field induced into the vehicles and scattered by them. However, analyzing these imperfections using the method of moments presents challenges, especially in mesh generation and numerical simulation. The paper shows that accurately reproducing the impact of these imperfections on the field is possible by adding small RWG basis function 'patches' to a smooth mesh that does not include the imperfections. These patches enable the evaluation of electric and magnetic currents through the appropriate polarizabilities.