Field structures of waveguide Y -junction circulators containing irregular shaped ferrite material,suc h as Y -junction with partial-height cylinder/triangle ferrite posts and metal step impedance transformer, Y -junction with a ferrite sphere, and dual higher order modes circulator,whic h are classified as different junction resonance modes, are depicted to illustrate the circulating process. The analysis method used is a combination of the mode expansion method and finite element method,whic h is based on the weak form of Helmholtz equation. Calculated results (return loss,insertion loss and isolation) of these structures are shown and compared respectively to those in literatures. Consistencies have been observed.