  The traditional finite-difference time-domain (FDTD) method is constrained by
the Courant-Friedrich-Levy (CFL) condition and suffers from the notorious
staircase error in electromagnetic simulations. This paper proposes a
three-dimensional conformal locally-one-dimensional FDTD (CLOD-FDTD) method to
address the two issues for modeling perfectly electrical conducting (PEC)
objects. By considering the partially filled cells, the proposed CLOD-FDTD
method can significantly improve the accuracy compared with the traditional
LOD-FDTD method and the FDTD method. At the same time, the proposed method
preserves unconditional stability, which is analyzed and numerically validated
using the Von-Neuman method. Significant gains in Central Processing Unit (CPU)
time are achieved by using large time steps without sacrificing accuracy. Two
numerical examples include a PEC cylinder and a missile are used to verify its
accuracy and efficiency with different meshes and time steps. It can be found
from these examples, the CLOD-FDTD method show better accuracy and can improve
the efficiency compared with those of the traditional FDTD method and the
traditional LOD-FDTD method.
