FEM analysis of coplanar waveguide with ferrite magnetised in an axial or transverse direction

A detailed analysis of a sandwich coupled slotline with axially or transversely magnetised ferrite layer has been carried out by using the finite element method (FEM) with edge elements. Comparison of the dispersion characteristics and phase shift shows that the variable reciprocal phase shift is larger with an axial bias field than with a transverse field, and that the non-reciprocal phase shift per unit length (with transverse field) increases with frequency whereas the reciprocal phase shift per unit length (with axial field) decreases with frequency. Also conductor-backed coplanar structures may be more suitable than suspended structures.