A phenomenological spice model for magneto‐impedance sensors

Abstract

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 Padé'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.

A novel magneto‐impedance sensor model based on the zeros of Bessel functions

“…With the aim of validating the model, a magnetic microwire with Co 70.5 Fe 4.5 Si 12.5 B 12.5 nominal composition was produced by the Taylor–Ulitovski technique, with an amorphous metallic nucleus of diameter 24 µm and total diameter of 40 µm . The electrical impedance was measured by means of the four‐point technique, with an AC electric current flowing along the microwire with an amplitude of 5 m A rms and a frequency range from 700 KHz to 7 MHz and illustrated in Figure .…”

“…In particular, different electromagnetic materials have been used to fabricate magneto‐impedance sensors based on single wire or multi‐wires . Moreover, several efforts have been realized to model and obtain an equivalent circuit that can be used to implement magneto‐impedance sensors . Valenzuela modeled the Giant Magneto‐Impedance effect in terms of simple circuits based on resistors, inductors, and capacitors, but the work was focussed on the magnetic permeability model and the magnetization process of amorphous ferromagnetic wires .…”

“…However, they only obtained transfer functions based on mathematical concepts, but they did not tested these functions with electrical circuits. A lumped circuit model for magneto‐impedance sensors was proposed by De la Cruz Blas et al in , which is based on the equivalent circuit of a Padé approximation derived from the impedance relied on Bessel functions. Here, magneto‐impedance sensors are mathematically studied using a new model based on polynomial functions involving zeros Bessel functions, and its electrical implementation is realized using second‐generation current conveyors (CCIIs), resistors, and inductors.…”

“…In Section 3, a new mathematical model is proposed and deduced, which represents the equivalent impedance of the sensor based on ratio of polynomial functions that are expressed in the form of poles and zeros. In Section 4, the mathematical evaluation of the model is realized for different number of zeros and poles and compared with results reported in . In Section 5, an impedance equivalent circuit based on CCIIs, resistors, and inductors is proposed and simulated through SPICE to corroborate the proposed mathematical model.…”