FDTD analysis of EM wave circulated by a magnetised ferrite body of arbitrary shape

An efficient numerical method has been devised for the study of a wave circulated by a magnetised ferrite body of an arbitrary shape. It is a finite-difference time-domain formulation that incorporates Mur's absorbing boundary conditions and a perfectly matched layer. Several shapes of interest have been studied, including spheres and circular cylinders. The electromagnetic fields inside the ferrite and the power-density distribution on the ferrite's surface normal to the bias external magnetic field are obtained. It is observed that an incident wave would circulate around the magnetised ferrite body in an open space as if the ferrite were placed inside a waveguide junction circulator. The technique is also extended to analyse the electrical performance of waveguide junction circulators. Various wave circulation characteristics are examined, and good agreement is observed between the numerical results and the measured data.