Efficient Algorithm for the Unconditionally Stable 3-D ADI–FDTD Method

This letter presents a new efficient algorithm for the unconditionally stable three-dimensional alternating direction implicit finite-difference time-domain (3-D ADI-FDTD) method. The algorithm involves updating equations whose right-hand sides are much simpler and more concise than those in the conventional implementation. This leads to substantial reduction in the number of arithmetic operations required for their computations. To take full advantage of the efficiency gain, efforts are made as well to maintain or reduce other computation costs in for-looping and solving tridiagonal systems. Certain field array reuse is also exploited which reduces the memory space and the memory indexing overhead