Hybrid Finite Element Method for Reconstructing Electric Field Distribution of Dielectric Object Excited by Dipole Antenna

This paper presents an inverse method to reconstruct an antenna-excited electric field distribution of a dielectric object from measured field data, for the purpose of noninvasive SAR evaluation in the human phantom. The proposed method is a hybrid method combining the Boundary Integral Equation (BIE) and Finite Element Method (FEM). The BIE for the electromagnetic (EM) fields and equivalent currents of a radiating source are discretized using the method of moments (MoM) while EM fields in the scatterer and its surroundings are discretized using the FEM. The effectiveness of the method is tested numerically and experimentally using a dipole and a dielectric cuboid at 2.5 GHz. The numerical reconstruction achieves acceptably good agreement with that of reference as a whole. However, it is found from the experiment that the method is considerably sensitive to the measurement error. The factors that may have contributed to the errors are shortly discussed.