Conjugate gradient method applied to inverse scattering with no prior information on incident field

摘要

A novel inverse scattering approach to estimate the permittivity profile of an unknown scatterer of interest without explicit knowledge on incident wave illuminating the scatterer is presented. The approach is based on the field equivalence principle. In the interior equivalent problem, where original field exists in the interior region while in the exterior region a zero field, a scatterer in the interior region should be the same as the original one. If the original scatterer is replaced by a different one, the total field in the exterior region becomes a non-zero field. From this observation, a functional which is the magnitude of the total electric field on a closed curve surrounding the interior region is introduced. The functional is minimized by the conjugate gradient method. Numerical simulations for some two dimensional scatterers are carried out to show the effectiveness of the proposed method.