Finite-Difference Time-Domain analysis of microwave ferrite devices

Finite-Difference Time-Domain Method is extended to gyromagnetic media using a time domain approach by solving Maxwell´s curl equations and equation of motion of the magnetisation vector in consistency. New update equations are derived to include finite size ferrite material magnetized in a general direction. New code includes non-uniform magnetization due to demagnetization effects as well. In order to validate our formulation, a full wave analysis of a thin film isolator is performed in 3D. Numerical results are then compared with measurements and a good agreement has been achieved. The method presented in this paper can be applied for other microwave ferrite devices such as circulators and phase shifters.