Microwave imaging 3-D buried objects using parallel genetic algorithm combined with FDTD technique

A microwave imaging technique based on the parallel genetic algorithm (PGA) and the finite-difference time-domain (FDTD) method is proposed in this paper for estimating the locations, dimensions and dielectric permittivity distributions of three-dimensional (3-D) objects buried in the lossy earth. The GA, a robust stochastic optimization procedure, is employed to recast the microwave imaging problem, an inverse scattering problem, to be a global nonlinear optimization problem and solve it. To reduce its heavy computation burden, the GA-based inverse computation is parallelized and run on a cluster system. A 3-D FDTD method with perfectly matched layer (PML) absorbing boundary condition (ABC) is selected for the forward calculation of the scattered field by the buried object. Sample numerical results are presented and analyzed. The analysis of the numerical results shows that the proposed microwave imaging technique based on the PGA and FDTD is able to recover the locations, dimensions and permittivity parameters of 3-D buried objects, and the parallel computation can sharply reduce the required computation time.