Multiferroic Resonant MEMS Magnetometer Strain Modulation
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Solution Overview
Problem
Current magnetic field sensors for on-body applications are either excessively large or consume high power, failing to provide the necessary sensitivity and low noise required for effective biomagnetic signal detection.
Innovation Solution
The development of multiferroic resonant MEMS magnetometers with a strain modulation technique, utilizing a piezoelectric and magnetostrictive material combination to upconvert low-frequency magnetic fields to the resonance band, maintaining a small die size and low power consumption while achieving high sensitivity and low noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field sensors are used for on-body applications, then sensitivity and noise performance can be achieved, but the sensor size and power consumption become excessively large
Solution Approach 1:
The patent merges the piezoelectric and magnetostrictive materials into a single integrated multiferroic sensor structure, combining multiple functions (actuation, sensing, and magnetic field detection) into one compact device. This integration eliminates the need for separate components, achieving high sensitivity while maintaining a small sensor footprint of 2.25 mm²
Solution Approach 2:
The patent utilizes mechanical resonance at specific frequencies to enhance the sensor's sensitivity. By operating the multiferroic material at its resonant frequency, the system achieves amplified response to magnetic field changes, enabling high measurement precision within a compact form factor
2Measurement precision
If conventional magnetic field sensors are used for on-body applications, then sensitivity can be achieved, but power consumption becomes excessively high
Solution Approach 1:
The patent employs periodic strain modulation at the resonant frequency to upconvert low-frequency magnetic field signals. This periodic action enables the sensor to achieve high sensitivity through resonant amplification while consuming minimal power (13 mW), as the system only requires small oscillating strains to achieve significant signal enhancement
Solution Approach 2:
The patent changes the operating parameters by modulating the strain rate and frequency to match the resonant characteristics of the multiferroic material. This parameter optimization allows the sensor to achieve maximum sensitivity with minimum power input, resolving the contradiction between measurement precision and energy consumption
3Measurement precision
If strain modulation technique is used to upconvert signals, then sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by using the multiferroic material's inherent piezoelectric and magnetostrictive properties to automatically perform signal upconversion. The material itself generates the strain modulation when exposed to magnetic fields, eliminating the need for external modulation circuits or additional actuation mechanisms, thus improving sensitivity without significantly increasing device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables high sensitivity and low noise performance with sensitivities of 58.4 mA/T and 37.7 mA/T and resolutions of 5.03 nT/√Hz and 2.72 nT/√Hz, respectively, while maintaining a small die size of 2.25 mm² and low power consumption of 13 mW, effectively addressing the limitations of existing sensors.
Implementation Method 1
a piezoelectric portion; a plate portion comprising (i) a drive electrode superposed over the piezoelectric portion and in mechanical communication with the piezoelectric portion
Implementation Method 2
the drive electrode comprising a magnetostrictive material and (ii) a sense electrode superposed over the piezoelectric portion and in mechanical communication with the piezoelectric portion, the sense electrode comprising a magnetostrictive material
Implementation Method 3
Two resonant plate designs operating in the MHz regime are explored, implementing a strain modulation technique to upconvert low frequency magnetic field signals to the resonance band of the plates, utilizing the high device Q factors
Data Source
AI summary
A magnetic field sensor component, comprising: a piezoelectric portion; a plate portion comprising (i) a drive electrode superposed over the piezoelectric portion and in mechanical communication with the piezoelectric portion, the drive electrode comprising a magnetostrictive material and (ii) a sense electrode superposed over the piezoelectric portion and in mechanical communication with the piezoelectric portion, the sense electrode comprising a magnetostrictive material; and a tether portion extending from the plate portion, and the magnetostrictive drive electrode being configured to be electrically driven so as to effect a strain modulation of the magnetostrictive drive electrode that upconverts a received magnetic field to a resonance band of the magnetostrictive drive electrode. A method, comprising operating a magnetic field sensor component according to the present disclosure.