Inverse scattering for monochromatic phaseless measurements

Abstract

An inverse method and measurement setup for profile and constitutive parameters reconstruction from monochromatic phaseless information is presented. The method is based on the minimization of a cost function that relates the measured field with the one scattered by a model of the object under test (OUT), where the position, contour, and constitutive parameters are the unknowns. As a result, phaseless information is directly related to the inverse problem unknowns, thus avoiding the need of an intermediate phase retrieval step. Due to the nonlinear nature of the cost function, global optimization techniques, such as the particle swarm optimization and differential evolution algorithms, have been considered for cost function minimization. An exhaustive analysis of the cost function behavior as a function of the electric size of the OUT is presented, discussing the optimal OUT size where the proposed methodology provides accurate profile and constitutive parameters reconstruction. The proposed methodology is conceived to use it together with a simple, low-cost measurement setup for fast characterization of perfect electric conductor and dielectric objects. Measurement examples are presented aiming to prove the feasibility of the described measurement setup