Abstract: To analyze the scattering with cylindrical wave illumination, a line source excitation method in the 2D ADI
FDTD method is discussed. The source excitation is imposed to both the first and
the second subiterations simultaneously, rather than forced in the first subite
ration only. In order to verify the proposed scheme the scattering problem of a
conducting cylinder illuminated by a line current source is treated. The ADIFD
TD result is in good agreement with the closed form solution. Also, the scatteri
ng of a 2D airfoil model is computed, showing the practical applicability of the
presented scheme. The timestep size in ADIFDTD is no longer restricted by t
he
Courant condition. If the cell size discretized in space is smaller, the 2D ADI
FDTD method is more efficient than the conventional FDTD method.

Key words: alternating direction implicit finite difference time domain(ADI-FDTD) method, cylindrical wave, radiation pattern, absorbing boundary condition