System for an acoustically driven ferromagnetic resonance sensor device
Inventors
Labanowski, Dominic • Salahuddin, Sayeef
Assignees
Publication Number
US-12366618-B2
Publication Date
2025-07-22
Expiration Date
2040-12-14
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Abstract
A system for an acoustically driven ferromagnetic resonance (ADFMR) based sensor. The system may include a power source, that provides an electrical signal to power the system, at least one circuit comprising a set of ADFMR circuits, sensitive to external electromagnetic fields, a power splitter, a power combiner and a detector circuit. The system functions to detect and measure external electromagnetic (EM) fields by measuring a perturbation of the electrical signal through the ADFMR circuits due to the EM fields.
Core Innovation
The invention described is a system and method for an acoustically driven ferromagnetic resonance (ADFMR) based sensor capable of detecting and measuring external electromagnetic (EM) fields. The system includes a power source that generates an electrical signal, one or more ADFMR circuits containing ADFMR devices that perturb the electrical signal in presence of EM fields, a power splitter and combiner to manage signal paths, and a detector circuit to determine EM field properties from the signal perturbations. The ADFMR device typically comprises a piezoelectric substrate with acoustic transducers and a ferromagnetic material through which acoustic waves propagate and are influenced by magnetic resonance, thus modifying the electrical signals.
The problem being addressed is that existing ferromagnetic resonance (FMR) sensing techniques rely on large, high-power, and complex laboratory setups unsuitable for integration into compact devices or production-ready systems. Other magnetic sensors like SERF and SQUID provide high sensitivity but are large and complex, while smaller sensors such as Hall effect and magnetoresistive sensors suffer from lower sensitivity. There is a need for a chip-scale, high-sensitivity, low-noise, and low-power magnetic sensor system that can be integrated into circuits and overcome size, power, and complexity limitations associated with current technologies.
This system aims to provide a compact, chip-scale ADFMR sensor solution with CMOS-compatible processing, enabling easy circuit integration and scalable production. By using acoustically driven magnetic resonance, the system achieves enhanced sensitivity over a broad frequency spectrum, low power consumption, and reduced heat generation. These features allow the sensor to perform precise EM field measurements in applications where previous FMR methods were impractical due to size, power, or noise constraints.
Claims Coverage
The patent claims cover a system comprising a power source, multiple ADFMR circuits arranged in parallel, power splitters and combiners, and detector circuitry. The claims include interferometer and gradiometer configurations, various circuit subcomponents, multidimensional sensing capabilities, and components for signal processing and measurement optimization.
System with parallel acoustically driven ferromagnetic resonance circuits
A system including a power source with an electronic oscillator, first and second ADFMR circuits connected in parallel, a power splitter upstream splitting the electrical signal into test signals for the ADFMR circuits, a power combiner downstream combining their outputs, and a detector circuit that determines EM field perturbations from the signals.
Interferometer circuit incorporating reference circuitry
An interferometer configuration where at least one signal processing circuit acts as a reference circuit situated parallel to an ADFMR test circuit, enabling measurement of EM fields via interference between perturbed and unperturbed signals.
Inclusion of matching networks, attenuators, and phase shifters in ADFMR circuit
Use of upstream and downstream matching networks, attenuators, and phase shifters within the ADFMR circuit to optimize signal power, impedance matching, and implement constructive or destructive interference.
ADFMR devices as surface acoustic wave devices with distinct sensing orientations
ADFMR devices comprising surface acoustic wave (SAW) devices, including configurations where multiple ADFMR devices within a circuit have distinct spatial orientations for multidimensional sensing.
Use of vector modulator and IQ mixer circuits for enhanced signal processing
Incorporating a vector modulator circuit parallel to the ADFMR circuit to reduce noise, and an IQ mixer circuit upstream of the detector to measure amplitude and phase of signals through linear combinations of orthogonal power signals.
Linearization circuit with feedback for optimized measurement regimes
A linearization circuit comprising an EM field source directed at the ADFMR circuit, a comparator, and a logic circuit to adjust the applied EM field and bring the system into an optimal field measuring regime via setup mode.
The claims comprehensively cover a system utilizing acoustically driven ferromagnetic resonance for EM field sensing, including parallel test circuits, interferometer and gradiometer configurations, signal processing enhancements, multidimensional sensing, and control circuits for optimizing measurement accuracy and sensitivity.
Stated Advantages
Provides a compact, chip-scale magnetic field sensor that overcomes the size limitations of traditional FMR systems.
Enables integration into circuit designs with CMOS-compatible processing for scalable and cost-effective production.
Offers enhanced sensitivity across a broad frequency range (0-10 GHz), improving over existing magnetic sensors.
Requires low power consumption, enabling operation in temperature sensitive environments with minimal heat generation.
Facilitates multidimensional and gradient field measurements with flexible circuit configurations.
Documented Applications
Mechanical sensor devices requiring precise field measurement.
Magnetic imaging applications.
As a replacement or alternative to SQUID devices for magnetic sensing.
Magnetoencephalography systems used to measure brain activity by monitoring neuronal fields.
General field measurement applications that benefit from a compact, low-power, high-sensitivity sensor.
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