Microwave sub-surface imaging using scattered-field calibration technique

A novel microwave sub-surface imaging scheme based on a scattered-field calibration technique is proposed in this paper. In this framework, the scattering parameters of the test object using the standard RF measurement system is first transformed into the electric field data. The transformation is based on measuring the scattering parameters of a known specimen under the same test environment, and then comparing the scattering parameters of this specimen with that of the test object under the assumption that electric field of the known specimen is computed in advance. The RF measurement system comprises of a transmitter-receiver array wherein the region under observation is illuminated sequentially. The solution of the inverse scattering problem is based on iterative distorted Born approximation. The performance of the proposed method is evaluated by means of numerical simulations and their inversion results.