Electromagnetic scattering by a perfectly conducting patch array on a dielectric slab

The scattering characterization of an infinite and truncated periodic array of perfectly conducting patches on a dielectric slab is discussed. In particular, an approximate solution for the truncated array scattering that is based on the exact solution for the corresponding infinite array is presented. The latter is obtained numerically by solving for the patch currents using a conjugate-gradient fast Fourier transform (FFT) technique, eliminating the need to generate and store the usual square impedance matrix. The scattering pattern of the finite array is then computed approximately by integrating the infinite-period-array currents over the given finite array. Numerical results are presented for the infinite and finite arrays, and the accuracy of the approximate solution for the finite array is examined and discussed in relation to some available exact data. It is found that the approximate solution is of reasonable accuracy in predicting the scattering by the truncated array