An FFT-based formulation for 3D PEC scatterers in the resonance region

The computation of time independent scattering from perfect electrically conducting (PEC) objects has been dominated by the method of moments (MoM) applied either to the electric field integral equation (EFIE) or the magnetic field integral equation (MFIE). Shen (1990) has, however, devised a way to apply a FFT-based algorithm to 2 flat PEC plates forming either an orthogonal or a non-orthogonal dihedral reflector. These plates are essentially 2D PEC plates and hence the correct boundary condition of the zero total electric field on the PEC surface can be properly applied. Shen obtained good agreement between the computed and measured far fields for plane-wave incidence on 2.5*2.5 wavelength and 5.6*5.6 wavelength dihedral reflectors. The present paper extends Shen´s work into the 3rd dimension to show for the first time that FFT-based algorithms can be applied to 3D PEC scatterers which may be open or closed structures