A Study of Excitation Source in FDTD Calculation

A new source which has a rectangular spectrum is proposed for the FDTD analysis of waveguide discontinuity.The source has high excitation efficiency and can filter out all undesired frequency components which are under the cut off frequency of the dominant mode and makes the calculation operating on a single dominant mode condition.Compared with the convention Gaussian pulse excitation,a practical calculation shows that both the CPU time and the memory requirement is greatly saved.