Ultra-wideband radar imaging experiment for verifying super-resolution in nonlinear inverse scattering

The super-resolution phenomenon in nonlinear inverse scattering has been reported previously using numerically simulated data. What was shown was the ability of a nonlinear inverse scattering method to resolve features that are much less than half a wavelength, the criterion dictated by the Rayleigh criterion. The phenomenon has been attributed to the multiple scattering effect within an inhomogeneous body. The high spatial frequency (high resolution) information of the object is usually contained in the evanescent waves when only single scattering physics is considered. Multiple scattering converts evanescent waves into propagating waves and vice versa. Hence, in an inverse scattering experiment, even though an object is interrogated with a propagating wave, and only scattered waves corresponding to propagating waves can be measured, the scattered waves contains high resolution information about the scatterer because of the evanescent-propagating waves conversion in a multiply scattered field. Therefore, an inverse scattering method that can unravel the multiple scattering information can extract the high resolution information on a scatterer.