A Simple Approach for Estimating the Effective Electric Parameters of 2-D Targets

In this paper, we introduce a simple, noniterative algorithm to estimate the effective dielectric properties of unknown targets from the measurements of their backscattered fields. The proposed approach relies on the virtual experiments concept, as it exploits a combination of the incident fields to be able to focus the exciting field on a certain region. Then, it associates the effective parameters to the permittivity and conductivity values that minimize the mean square error between the virtual scattered field (obtained by recombining the measured data) and the field scattered by a homogeneous dielectric cylinder centered on the target, having approximately the same area. The center of this effective scatterer and its radius can be estimated with a qualitative imaging algorithm or can be given as a priori information. Notably, by properly designing the virtual incident fields, the proposed method can easily handle the case of multiple targets. The effectiveness of the method is assessed by both numerical and experimental examples.