A new 2-D image reconstruction algorithm based on FDTD and design sensitivity analysis

This paper proposes a numerical algorithm that reconstructs the complex permittivity profile of unknown scatterers by the design sensitivity analysis (DSA) and topology optimization technique. By introducing the DSA and adjoint-variable method, the derivatives of the error function with respect to the complex permittivity variables can be calculated, and the material property in each cell can be changed simultaneously using sensitivity information. The steepest descent method is used as an optimization technique. The proposed method is validated by applying it to reconstructions of unknown two-dimensional scatterers that are illuminated by TM^z with a Gaussian-pulsed plane wave.