A Hybrid Method for Solving 2-D Inverse Scattering Problems

Abstract

In this chapter, hybrid method for solving two-dimensional inverse scattering problems is illustrated. In this method, a two-step optimization-based routine is used in which direct and expansion methods are utilized simultaneously to obtain more precise and fast reconstruction. In the first step, a coarse solution is achieved with the help of truncated cosine Fourier series expansion method. Then, with this solution as an initial guess for the second step, direct optimization is used to obtain a much more accurate solution of the problem. In both steps, finite difference time domain and differential evolution are used as an electromagnetic solver and global optimizer, respectively. The most important advantage of this method is that because of a suitable initial answer in direct optimization routine, sensitivity of the algorithm to the regularization parameter is decreased and convergence of the results is completely guaranteed. Performance of the proposed method is demonstrated for several two-dimensional relative permittivity profile reconstruction cases.