Reconstructing perfectly electric conductors by the subspace-based optimization method with continuous variables

In this paper, an improved version of the subspace-based optimization method (SOM) is proposed to reconstruct perfectly electric conductor (PEC) scatterers using electromagnetic scattering data. The background medium, together with scatterers of arbitrary number and arbitrary shapes, is effectively expressed as a vector that facilitates to build up the objective function. No a priori information, such as the number of the objects and their approximate locations or centers, is needed. The contrast source inversion method is applied to optimize the inverse problem. The proposed method is found to be more robust against noise and requires less computational resource than the original SOM for PEC scatterers.