Inverse scattering problems of near-field subsurface pulse diagnostics

摘要

Methods of near-field subsurface electromagnetic diagnostics that provides a subpulse-length resolution are developed and studied in experiments with the pulse microwave source-receiver scanning system. Proposed tomography and holography of subsurface dielectric targets are based on the solution of 3D near-field inverse scattering problems by 2D measurements of the scattered pulse signal above the surface of media with dielectric inhomogeneities. Pulse data are transformed to frequency domain, where, using the Green function formalism, the non-linear 3D integral equation has been obtained to solve this inverse scattering problem. The solution of this equation is used to derive tomograms of distributed inhomogeneities or to determine the shape of solid targets for further visualization as holography images. To retrieve depth profiles of one-dimensional subsurface inhomogeneities of sand density, the dual regularization method has been worked out and tested by experimental data.