Efficient FDTD wideband matched sources for a homogeneous waveguide cross-section

A finite difference time domain (FDTD) wideband matched source, for waveguide problems, is developed by the FDTD diakoptics method. The efficiency of this matched source is obtained by using the modal amplitude, instead of the 2-D transverse field, to represent the incident and reflected waves. The performance of this matched source is demonstrated by the S-parameter calculation of an inductive iris and a back short. Comparisons with other matched sources with first-order absorbing boundary condition (ABC) and superabsorbing conditions are also provided.