Application of microgenetic algorithm for nonuniform mesh artificial anisotropy alternating-direction-implicit-finite-difference time-domain method

A new method to reduce the numerical dispersion of the conventional alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is proposed. First, the numerical formulations are modified with the artificial anisotropy, and the numerical dispersion relation is derived. Second, the relative permittivity tensor of the artificial anisotropy can be obtained by the microgenetic algorithm (MGA), which is a genetic algorithm with a very small population. Then, the capabilities and potentialities of this new method are demonstrated numerically using two nonuniform-mesh examples. The numerical results of the proposed method are compared with those of the FDTD method and the conventional ADI-FDTD method, respectively. Furthermore, the reduction of the numerical dispersion is investigated as the objective function of the MGA. It is found that this new method is accurate and efficient by choosing proper objective function.