Effective permittivity of finite inhomogeneous objects

摘要: A generalization of the S-parameter retrieval method for finite three-dimensional inhomogeneous objects under arbitrary illumination and observation conditions is presented. The effective permittivity such may be rigorously defined as a solution nonlinear inverse scattering problem. We confirm analytically observe numerically effects that were previously reported in one-dimensional strongly slabs: nonuniqueness its dependence on conditions, geometry object. Moreover, we show that, although scale free at level problem statement, exact this either does not exist or unique. Using results from spectral analysis describe set values which ill-posed. Unfortunately, real nonpositive values, important negative refraction invisibility, belong to set. illustrate our conclusions using numerical reduced-order algorithm specifically designed