On the implementation of the conjugate gradient Fourier transform method for scattering by planar plates

The accuracy of two conjugate gradient fast Fourier transform formulations for computing the electromagnetic scattering by resistive plates of an arbitrary periphery is discussed. One of the formulations is based on a discretization of the integral equations prior to the introduction of the Fourier transform, whereas the other is based on a similar discretization after the introduction of the Fourier transform. The efficiency and accuracy of these formulations are examined by comparison with measured data for rectangular and nonrectangular plates. The latter method is found to provide a more accurate computation of the plate scattering by eliminating aliasing errors (other than those due to undersampling). It is also found to be substantially more efficient. Its greatest advantage is realized when solving large systems generated by convolutional operators not yielding Toeplitz matrices, as is the case with plates having nonuniform resistivity.<>