Analysis of a Ka-band microstrip-to-waveguide transition by the FDTD expanding-cell algorithm

In this paper, we suggest the FDTD expanding-cell algorithm to analyze the characteristics of a microstrip line to rectangular waveguide transition. The transition under investigation consists of a discontinuity between a ridged waveguide, microstrip line and a ridged waveguide impedance transformer. The expanding-cell FDTD method is applied to analyze the ridged waveguide impedance transformer. The expanding-cell result is compared with fine cell, coarse cell, and experimental data.