Abstract
This article presents the pulse propagation characteristics through the via structures (via, pad, and clearance hole) by using the FDTD method. We investigated the size of the via structures so as to maximize the peak value of pulse responses for the Gaussian pulse incident with the pulse width from 0.2ps to 20.0ps. We showed that the pulse width is limited by the radius of via and the radius of pad. Numerical accuracy is investigated from the points of the sell size, the terminal conditions of microstrip line, and the distance between the exciting point and PML. The peak value of responses becomes smaller as the pulse width is reduced and the via radius is enlarged.
