ELECTROMAGNETIC WAVE SCATTERING BY QUASI-HOMOGENEOUS OBSTACLES

In this work we investigate the electromagnetic wave scattering phenomena by quasi-homogeneous obstacles, namely obstacles with wavenumber functions not exhibiting large variations from an average value k. First, we express the field coefficients by means of a T-matrix method for the corresponding piecewise-homogeneous scatterer and then perform the best linear approximation by dif-ferentials to express these coefficients as linear combinations of the distances of the wavenumber samples from k. Moreover, the total far-field pattern of the quasi-homogeneous scatterer is decomposed into that of the respective homogeneous scatterer with wavenumber k plus the perturbation far-field pattern, depending exclusively on the wavenumber’s deviations from k. Numerical results are pre-sented concerning (i) the far-field patterns, computed by the proposed technique and the T-matrix method, (ii) the variations of the perturbation far-field pattern, and (iii) the prediction of each layer’s contribution to the far-field