Electromagnetic inverse scattering based object imaging and characterization

Abstract

Summary form only given. Object imaging and object characterization based on electromagnetic inverse scattering involves retrieving the equivalent source from the scattered field measured outside the source region due to a known incident field. The solution to the inverse equivalent source problem is not unique. In (S. Shahir, M. Mohajer, A. Rohani, and S. Safavi-Naeini, “Permittivity profile estimation based on nonradiating equivalent source,” Progress in Electromagnetic Research B, Vol. 50, pp. 157-175, 2013), we estimated uniquely the scatterer permittivity profiles by minimizing the non-radiating objective function and applying the information of the scatterer locations and boundaries.Object imaging and object characterization of one and two dielectric cylinders are reported by Zakaria (A. Zakaria, I. Jeffrey, M. Ostadrahimi, M. Asefi and J. LoVetri, "A Novel 3D Near-field Microwave Imaging System," IEEE international symposium on Antennas and Propagation, pp. 816-817, 2013). Zakaria has been able to reconstruct the scatterers' cross sections. Some artifacts can be observed in the results. The reconstructed cross section of the circular cylinder is not circular. Ostadrahimi has done initial calibration by using a PEC circular cylinder to work around the issue (M. Ostadrahimi, A. Zakaria, J. LoVetri, and L. Shafai, "A Near-Field Dual Polarized Microwave Imaging System," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 3, 2013). In the aforementioned experiments, the mutual coupling between the adjacent probes was unavoidable, and the objects under test were small in terms of wavelength. We are going to present our experimental results for object imaging and characterization at 75-110 GHz. By calibrating the electromagnetic inverse scattering system accurately, we have successfully been able to reconstruct the large-size object images. The reconstructed objects are also to be characterized by minimizing the non-radiating objective function.