Integral equation boundary conditions for the efficient FDTD analysis of low-frequency transient problems

Innovative boundary conditions are proposed for the efficient truncation of FDTD grids in the analysis of low-frequency transient problems, in which the minimum excited wavelength is hundreds times greater than the space discretization step. The electromagnetic transient source is coupled inside the discretized FDTD domain by enforcing electric- and magnetic-field integral-equations on the grid borders. Critical aspects of the numerical implementation are discussed. Numerical applications demonstrate the validity of the proposed procedure.