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We investigate the imaging capabilities of a new linear microwave imaging approach, which allows to quantitative retrieve the complex permittivity distribution of unknown nonweak targets. To this end, we carry out a parametric numerical analysis for a canonical scatterer (a homogeneous dielectric cylinder with circular cross section) and derive a quantitative criterion to foresee the method’s applicability. The reliability of the criterion is then tested against noncanonical scatterers to show the effectiveness of the method in imaging nonweak targets and in outperforming the linearized inversion method based on the standard Born approximation.

An efficient inverse scattering strategy is proposed to achieve dielectric characterization of buried objects in lossy soils. The approach takes advantage of Virtual Experiments and Compressive Sensing to obtain quantitative reconstructions of nonweak targets which are nonsparse in the pixel representation basis, commonly adopted in microwave imaging. In addition, an original strategy is adopted to overcome the relevant information lack arising when data are gathered under aspect-limited configurations, such as in ground penetrating radar (GPR) surveys. The proposed strategy significantly outperforms the results achievable with the "state of the art" standard approaches since it allows to achieve nearly optimal reconstructions within a linear framework and without increasing the overall computational burden. Numerical examples with simulated data are given to show the feasibility of the proposed strategy.The last drawback can be circumvented, in principle, by adopting imaging recovery approaches based on the emerging framework of compressive sensing (CS) [Baraniuk, 2007;Donoho, 2006]. It offers a powerful framework to obtain satisfactory reconstructions of "sparse images," with the possibility to achieve nearly optimal reconstruction as well as superresolution. However, CS theory has been completely assessed only in the case of linear recovery problems [Baraniuk, 2007;Donoho, 2006] so that in subsurface microwave imaging,

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A novel approach to the design of cloaking devices is presented which takes inspiration from the Fourier diffraction theorem. In particular, we first put on a common basis different linear approximations of the scattering equations. Then, a very simple procedure to get invisibility (under the given approximation at hand) is proposed. The approach is assessed through numerical examples concerning 3-D non-canonical objects. INDEX TERMS Fourier diffraction theorem, inverse design, linear approximations, scattering.