Newmark algorithm in the finite-difference time-domain analysis of ferrite magnetized in an arbitrary direction

Abstract

The permeability tensor of saturated magnetized ferrite in frequency domain in the laboratory coordinate system is obtained by using the transformation matrix between the principal and laboratory system. The constitutive relation in time domain, which is a kind of second order differential equation, is derived by employing the transformation from the frequency domain jω to time domain ∂/∂t and solved by utilizing the Newmark algorithm. Consequently, a Newmark finite-difference time-domain method is proposed to deal with the problem of electromagnetic scattering by ferrite which is subjected to an external magnetic field in an arbitrary direction. The electromagnetic scattering by a magnetized ferrite layer and a sphere is simulated, and the numerical results demonstrate the validity and feasibility of the proposed method.