On the inverse source method of solving inverse scattering problems

The problem of solving the inverse scattering problem using the inverse source method is discussed. It is shown that the method, in general, gives rise to inaccurate solutions when the number of unknowns in the problem is increased. This is due to the presence of the non-radiating sources, and high-spatial-frequency currents that generate evanescent waves. Moreover, we show that the Green operator acts as a low-pass filtering operator, removing high-frequency information. The same problem is shown to be endemic from an operator viewpoint.