3D FDTD Program with Enhanced Electromagnetic Simulation Capabilities

Following our previous 1D and 2D FDTD implementations, we present this enhanced 3D FDTD program capable of solving complex three-dimensional electromagnetic scattering problems with broader application scope. The implementation features a main simulation loop that iteratively updates electric and magnetic fields using central difference approximations, with material parameters defined through epsilon and mu arrays. To run the program, users need to configure essential parameters including grid resolution (dx, dy, dz), time step (dt), and source excitation characteristics. The code architecture incorporates convolutional perfect matched layer (CPML) boundaries for absorption and supports various source types (Gaussian, sinusoidal, custom waveforms). Notably, this program extends beyond electromagnetics to related domains like optics and acoustics through parameter adaptation - for optical applications, users can modify permittivity distributions to model photonic structures, while acoustic simulations require adjusting density and speed of sound parameters. Its high practicality makes it valuable for researchers in related fields; we encourage experimentation with the provided examples demonstrating scattering cross-section calculations and near-field visualization.