Multifrequency dielectric profile inversion for a cylindrically stratified medium

The linear and the quadratic Born approximations of the inverse scattering problem are analyzed in the case of multifrequency measurements. The attention is focused on the determination of the maximum number of independent data available to perform the inversion for a fixed frequency interval. This number is obtained by performing the Fourier transform of the field scattered by the object under test and calculating its bandwidth under both the approximations. The results were that the quadratic model allows the authors to achieve a double number of independent data, changing the class of profiles that can be reconstructed with respect to the linear model. In order to show the validity of this conclusion, a numerical example of inversion under the two different models is performed.