Time-domain model of complex media: Application to non-saturated and non-homogeneously magnetized ferrite medium

Ferrite material plays an important role in modern microwave components such as isolator, circulator and phase shifter. Also, they provide some agility to externally tune devices by adjusting a DC magnetic field which modifies the constitutive parameters. However, ferrite medium is complex and elaborated modelling procedures are required to carry out full-wave electromagnetic simulation. A general TLM (Transmission-Line Matrix) procedure is proposed to model those media in time-domain. It accounts for effects such as non-homogeneous DC magnetization and arbitrary magnetization state by inserting a physical causal model and coupling static simulation to accurately account for the demagnetization field which depends also on the ferrite sample geometry.