C Implementation of 3D FDTD Yee Algorithm for Free Space Simulations

This straightforward C code implements the 3D Finite-Difference Time-Domain (FDTD) method using Yee's algorithm, solving Maxwell's equations in free space on a Cartesian grid. The implementation features a simplified rectangular waveguide model with Perfect Electric Conductor (PEC) boundary conditions, using a leapfrog time-stepping approach with spatial staggering of electric and magnetic field components.