A signal processing approach to finite-difference time-domain computations

The FDTD method is used to find numerical solutions to Maxwell's equations when analytic ones are prohibitive. Brute force approach to the FDTD method requires costly calculation at every point in the solution grid. If the solution is required at only a subset of the domain, then some computing time can be saved by expressing a portion of the grid as an LTI system with inputs and outputs. The output then becomes a convolution of the input with the LTI impulse response. We show how the impulse response is derived from the FDTD algorithm and how a reduction in the computation time is achieved