A BANDPASS SOURCE TECHNIQUE FOR THE FDTD ANALYSIS OF WAVE-GUIDE DISCONTINUITY

A new source which has a bandpass spectrum has been proposed for the F DTD analysis of waveguide discontinuity. Compared with the Gaussian pu lse source, a significant computational time saving is achieved by usi ng the new source. The new source can filter out all undesired frequen cy components. With this excitation scheme, the whole system of invest igation can operate under the predesigned frequency band, and stabilit y can be quickly reached in the FDTD calculation. In addition, by usin g the new source, the FDTD calculation can prevent the effect of unabs orbed frequency components which often requires a sufficiently large c omputation region. To demonstrate the validity and efficiency of this source scheme, numerical results for a rectangular waveguide containin g a dielectric layer are given, compared with the data of Gaussian pul se excitation that have been published. (C) 1998 John Wiley & Sons, In c.