Two-dimensional dielectric profile reconstruction based on spectral-domainmoment method and nonlinear optimization

A novel method for two-dimensional (2-D) profile reconstruction of dielectr ic objects, based on nonlinear optimization, is presented in this paper, Th e unknown dielectric profile is expressed in terms of Gaussian basis functi ons. The scattering integral equation (SIE) is discretized using a spectral -domain moment technique, where the unknown internal field is described as a superposition of a limited number of plane waves, resulting in a signific ant reduction of the associated computational cost, The inverse-scattering problem is solved by minimizing a cost function consisting of two terms: th e first term represents the error between measured and predicted values of the scattered field, while the second term corresponds to the error in sati sfying the SIE for the field in the interior of the scatterer, Accurate and efficient dielectric profile reconstructions of 2-D lossy scatterers of ci rcular and square cross sections using synthetic scattered field data are p resented, while the effect of various discretization parameters on the conv ergence of the method is studied in detail.