Hybrid sub-gridded ADE-FDTD method for modeling ground-penetrating radar on dispersive soils

Abstract

Based on the sub-gridding scheme, a hybrid method with explicit finite-difference time-domain (FDTD) and implicit Crank–Nicolson (CN) FDTD is presented for ground-penetrating radar (GPR) simulations on dispersive and conductive soils in this paper. The time step of CN-FDTD can be set to a large value so that the whole region can be run with a common time step determined by the coarse grid in a stable fashion. The missing information in the sub-gridded border region is obtained with an interpolation in space. The dispersion of the soil is modeled by a multi-pole Debye model and is solved with auxiliary differential equations (ADEs) for both FDTD and CN-FDTD. Additionally, examples of the GPR scenario are calculated to verify the accuracy and efficiency of the hybrid sub-gridded ADE-FDTD method.

Keywords:

• Crank–Nicolson finite-difference time-domain (CN-FDTD)
• dispersive media
• ground-penetrating radar (GPR) modeling
• sub-gridding scheme