Numerical evaluation of a full-wave antenna model for near-field applications

In this study, we numerically evaluated a full-wave antenna model for near-field conditions using GprMax3D. The antenna is effectively characterized by a series of source and field points and global reflection/transmission coefficients, which enables us to take the maximum benefit of using analytical solutions of Maxwell´ equations to noticeably reduce computation time compared to the numerical approach. The full-wave GPR model was calibrated by a series of numerical experiments above an infinite perfect electrical conductor (PEC). The calibration results provided a very good agreement with GprMax3D modeled data with a correlation coefficient of approximately 0.9995. Afterwards, the model was applied to estimate the dielectric permittivity and conductivity of an artificial medium based on GPR data obtained from the GprMax3D model. Full-wave inversion provided quite accurate estimations. The average relative errors of the dielectric permittivity and conductivity were lower than 0.28% and 11.5%, respectively. Our modeling approach shows a great potential to apply full-wave inversion for characterizing the electrical properties of the subsurface from near- and far-field radar measurements.