Microwave Imaging of Stratified Media From Band-Limited Reflection Coefficient Data

A novel analytical approach for the 1-D microwave imaging of the stratified dispersive media is presented. The proposed approach provides the depth-dependent permittivity profile of the target area in terms of the spectral-domain reflection coefficients, which are measured at the surface of the interrogating medium over a band of frequencies depending upon the available antennas and other measuring equipment. The inverse solution of the depth-dependent permittivity profile is obtained with the help of a newly derived integral transform, which is the amended form of the conventional Fourier transform valid under situations where the spectral-domain reflection data are present only over a band of frequencies. The derived inverse solution is also made applicable for the dispersive media, such as the rectangular waveguides, by facilitating the separation of spectral and spatial variables in an innovative way. The applicability of the proposed approach is validated by reconstructing the depth-dependent permittivity profiles of a number of multilayered and stratified media using both the simulated and the measured reflection coefficient data with the help of the developed algorithm.