Extraction of incident field from total field data

In this paper, an approach based on the field equivalence principle for obtaining the information of the incident field from total field data is presented. In general, the incident field is not easy to know because it is related to not only the impressed source but also the characteristics of the transmitting antenna and the surrounding environment of the source. By using this approach, the incident electric field is calculated from only total field data measured on a closed line, which is very useful for inverse scattering. Preliminary numerical simulations for some two dimensional scatterers show that the fields extracted from total field data are almost equal to the incident fields illuminating a scatterer of interest.