Perturbation Theory and Simulation Computation For Dual-mode Ferrite Devices

This paper started off with Maxwell formulae of gyro magnetic medium, deduced a series of perturbation formula for propagation constant and coupling coefficient under weak magnetic field, and further developed the perturbation theory for wave propagation and coupling in ferrite devices. To demonstrate the validation of perturbation formulae, some examples are compared with other solutions, such as the analysis approach based on wave-coupled theory and S-parameter method from simulation computation using HFSS EM field which are coincided with resultant of perturbation method