Methods of near-field subsurface diagnostics: Theory, study, comparison

Methods of electromagnetic near-field diagnostics of subsurface dielectric inhomogeneities are presented that are based on the solution of inverse scattering problems by data of 2D scanning with electrically-small probes that provide a subwavelength resolution. This diagnostics includes tomography of 3D distributed inhomogeneities 3D of complex dielectric permittivity and holography (shape reconstruction). Here, new methods of pulse, multifrequency and impedance diagnostics are studied. Results of theoretical and experimental studies of their efficiency are demonstrated.