Time domain finite difference calculations using a variable step size

The authors describe a novel method of computational electromagnetics which uses a variable step size (calculation increment) in the finite-difference technique (VSSFDM). The step size is kept small around discontinuities and larger away from them, thereby using only about 1/3 of the memory required by a straight application of K.S. Yee's (1966) method. The results obtained by VSSFDM are very close to those obtained by the finite-difference method, but with a significant reduction in the required computer memory as well as CPU time. The numerical stability of the proposed approach is demonstrated, and the VSSDM is applied to a symmetric microstrip with a width to height ratio of one.<
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