FAST IMAGING OF ELECTROMAGNETIC SCATTERERS BY A TWO-STAGE MULTILEVEL SAMPLING METHOD

Some effective imaging schemes for inverse scattering problems were recently proposed in [13, 14] for locating multiple multiscale electromagnetic (EM) scatterers, namely a combination of components of possible small size and regular size compared to the detecting EM Wavelength. In this paper, instead of using a single far-field measurement, we relax the assumption of one fixed frequency to multiple ones, and develop efficient numerical techniques to speed up those imaging schemes by adopting in and Multilevel ideas in a two-stage manner. Numerical tests are presented to demonstrate the efficiency and the salient features of the proposed fast imaging scheme.