基于 FEM-MEI 和正余弦算法的二维电磁成像方法

For electromagnetic imaging of two-dimensional dielectric targets, this paper proposes a new imaging method via combining the sine-cosine algorithm (SCA) with the finite element method (FEM) and the measured equation of invariance (MEI) . FEM and MEI are combined to solve the forward electromagnetic scattering problem of two-dimensional dielectric targets, namely the Helmholtz equation. MEI guarantees the accuracy of the boundary truncation, and FEM is suitable for accurate modeling complex dielectric targets. For the electromagnetic inverse scattering problem, a new reconstruction method is proposed based on an improved version of the sine-cosine algorithm. The scattering fields in the far region are obtained using the equivalence principle and the asymptotic expression of the Green’s function. The maximum deviation between the measured scattering fields and the calculated scattering fields is taken as the objective function. The medium parameters are optimized by sine-cosine algorithm to minimize the objective function, and the scatterer is reconstructed. Furthermore, the MPI parallel computing is adopted to improve computing efficiency. Finally, a reference function is used to demonstrate the fast convergence of the improved sine-cosine algorithm, and the correctness of the imaging method is verified by an irregular homogenous dielectric column object.