A phenomenological Spice model for magneto-impedance sensors

In this paper a lumped circuit model of magneto-impedance (MI) sensors that can be easily implemented in Spice-like simulators is proposed. The model is based on the equivalent circuit of a Pade’s approximation derived from the impedance relied on Bessel functions. Thus, the model can simulate the transient and frequency responses from DC to several megahertz for a fix external magnetic field. Besides, the model can predict the impedance changes of the sensors as a nonlinear function of an external magnetic field via behavioral sources. This allows simulating MI sensors using magnetic feedback for controlling their response to improve linearity and dynamic range. The model has been verified using Spice simulations together with measurement results from a discrete prototype for generating the pulse voltage source, a simple modulation-type configuration, and a feedback structure.