fdtd3d is an open source 1D, 2D, 3D FDTD electromagnetics solver with MPI, OpenMP, CUDA and ROCm support for x64, ARM, ARM64, RISC-V, PowerPC, Wasm architectures
gprMax is open source software that simulates electromagnetic wave propagation using the Finite-Difference Time-Domain Finite-Difference (FDTD) code for numerical modelling of Ground Penetrating Radar (GPR), antennas, radar and bioelectromagnetics