A new wideband matching boundary condition based on the transition operator for TD-FD method

A local wideband matching boundary condition (MBC) for the TD-FD (time-domain-finite-difference) method is introduced. The algorithm of the MBC is based on the transition operator concept. The reflection behavior of the MBC for the whole standard waveguide frequency band approaches the matching condition of a long homogeneous waveguide as the size of the mesh parameter Delta l is reduced. The MBC has very low reflections (better than 30 dB return loss for the waveguide width with 21 Delta l), making accurate S-parameter calculations possible with the TD-FD method. These features can be used to model general microwave and millimeter-wave waveguide discontinuities with a compact computational domain for S-parameter extraction.<>