Finite-difference time-domain (FDTD) full-wave analysis of several waveguide junction circulators with full-height ferrite posts of arbitrary shapes is presented. The structures contain T-junction, irregular T-junction, Y-junction, and Y-junction with a bend. Two ferrite shapes of interest are studied, including circular cylinder and triangular post, and the performance of the circulators is presented. Calculation results of the waveguide-junction circulators with circular ferrite post and triangular ferrite post obtained by the present analysis are compared with those from the field-matching and finite-element methods, respectively, as a reference, and better agreement is found in this study.