On the Use of an Equivalent Currents-Based Technique to Improve Electromagnetic Imaging

Accurate imaging from scattered field measurements is one of the main research topics in the field of non-destructive testing. Different methodologies for inverse scattering have been developed, ranging from backpropagation techniques to full-wave inversion methods. While far-field approaches are valid for the majority of the imaging systems, there are some scenarios where these approaches do not provide accurate modeling of the field radiated by the antennas of the imaging system. This results in some kind of distortion in the resulting output microwave images. To address this issue, proper characterization and modeling of the fields radiated by the antennas are required. This contribution proposes the use of an equivalent currents-based technique to characterize the transmitting and receiving antennas of the imaging sensor. The goal is to calculate accurately the field radiated by these antennas within the imaging domain, using it in the backpropagation algorithm. The methodology described in this contribution is supported by measurements for monostatic and multistatic configurations.Principado de Asturias/FICYT, “Ayudas Para Grupos de Investigación de Organismos del Principado de Asturias Durante el Período 2021–2023,” AYUD/2021/51706 Ministerio de Ciencia e Innovación, proyecto META-IMAGER, y proyecto RTI2018-095825-B-I00 (“Millihand”)