Buried crack reconstruction through far-field electromagnetic inverse scattering measurement

An alternative approach to common methods in NDT for detection and identification of buried rectangular cracks on PEC surface is introduced. Goals are reached by solving a far-field inverse scattering problem. This approach enables us to reconstruct dielectric filled cracks under one or more dielectric layers with no need to touch the surface by any probes, but rather by measurements in the far-field of an antenna array. Suggested solution is applied by both TEz and TMz polarizations to two-dimensional structures with various crack's depth-to-width ratios; approximations for long three-dimensional structures. PSO and DE optimizers are used to solve the inverse scattering problem and both optimizers contain FDTD technique as their scattering problem solver.