Numerical simulation using HIE-FDTD method to estimate various antennas with fine scale structures

The hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) method is employed to solve the problems of various antennas with fine scale structures. In this method, a larger time-step size than allowed by the CFL stability condition limitation can be set because the algorithm of this method is weakly conditionally stable. Consequently, an increase in computational efforts caused by fine cells due to thin slots or small substrate of antennas can be prevented. The results from the HIE-FDTD method agree well with results from the conventional finite-difference time-domain (FDTD) method, and the required CPU time for the HIE-FDTD method is much shorter than that for the FDTD method. Compared with the alternating-direction implicit FDTD (ADI-FDTD) method, the HIE-FDTD method has better accuracy and higher efficiency, which is demonstrated by numerical examples.