Low power acoustically driven ferromagnetic resonance (ADFMR) sensor arrays
Inventors
Labanowski, Dominic • Deka, Nishita
Assignees
Publication Number
US-12287383-B2
Publication Date
2025-04-29
Expiration Date
2041-09-30
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Abstract
Systems and method for a multi-array magnetic sensing component, which can include a circuit base platform; a set of magnetic sensors arranged on the circuit base platform; and a circuit system comprising intermediary circuit components, signal input, and a signal output, the signal input being an electrical oscillator signal input and being directable to each magnetic sensor in the set of magnetic sensors, the signal output including magnetic field measurements from the set of magnetic sensors, wherein each magnetic field measurement is individually selectable, the circuit system being configured to turn on or off subsets of the set of magnetic sensors, and the intermediary circuit components including a mixer.
Core Innovation
The invention presents a system and method for a multi-array magnetic sensing component that integrates a circuit base platform with a set of acoustically driven ferromagnetic resonance (ADFMR) magnetic sensors arranged on it. This system includes an oscillator providing electrical oscillator signal inputs directed through one or more input interdigitated transducers (IDTs) to the sensors, with a circuit system configured to selectively turn on or off subsets of the magnetic sensors. The signal outputs from these sensors, which represent magnetic field measurements, include intermediary circuit components such as a mixer, and each measurement is individually selectable.
The problem addressed by the invention concerns limitations in existing ferromagnetic resonance (FMR) and other magnetic sensing technologies. Existing FMR implementations typically require large cavities, high power, and use large sample volumes, restricting them to laboratory research and making them incompatible with device applications. Other sensitive magnetic sensors like SERF and SQUID devices are bulky, complex, and require extensive shielding and temperature control. Smaller sensors such as Hall effect sensors lack sufficient sensitivity for applications like brain monitoring. Therefore, there is a need for a new and useful system and method enabling flexible, small, portable, and easily modifiable FMR sensor arrays for a broad range of applications.
The invention provides such a system and method by implementing a compact, chip-based magnetic sensor array circuit featuring multiple ADFMR sensors on a circuit base platform. This system allows for multidimensional electromagnetic field measurements by enabling sharing of circuit components through time and/or frequency domain multiplexing, active or passive noise shielding, adjustable operational states for power conservation or sensing, and customizable sensor arrangements. The system includes components like electronic oscillators generating RF signals, mixers to process and normalize outputs, and processing systems to digitize and analyze sensor data. These features collectively enable a versatile, highly sensitive, low-power, spatially flexible sensor array suitable for many field measurement applications.
Claims Coverage
The claims disclose two independent systems focusing on multi-array magnetic sensing components involving ADFMR magnetic sensors arranged on a circuit base platform, coupled to an oscillator and controlled through a circuit system with intermediary components including a mixer.
Selective activation of ADFMR sensor subsets by electrical oscillator signals
The system includes a circuit base platform with ADFMR magnetic sensors arranged thereon and a circuit system configured to turn on or off subsets of these sensors via an electrical oscillator signal input, powering the subsets to be selectively active or inactive.
Multiplexing by frequency and time subsets of ADFMR sensors
The sensor set may include frequency subsets where each sensor operates at a distinct frequency bandwidth enabling frequency-identifiable outputs; and time subsets where sensors are turned on during distinct time intervals—either non-overlapping or with unique active/inactive patterns—allowing time-interval-based separation of sensor outputs.
Low power operating mode with trigger-based switching
The system supports a low power operating mode where only a fraction of the sensors operate continuously. A trigger signal can switch the system from low power to active mode where all sensors function. Similarly, the system can switch back to low power once sensor activity drops below a threshold.
Incorporation of magnetic shielding and field coils for noise cancellation and calibration
The system may include high permeability materials encircling the sensors for passive shielding. It may also include a field coil near the sensors that in a shielding mode generates magnetic fields to cancel environmental fields and in a calibration mode shifts field measurements into linear sensor regimes.
Flexible spatial arrangement and platform integration of sensors
The sensors can be arranged in two-dimensional hypersurface formations on a circuit base platform that may be an integrated circuit (IC) with both sensors and intermediary components on-chip, or a printed circuit board (PCB) with sensor ICs mounted on it, enabling versatile implementations and sensor groupings.
Intermediary circuit components including a mixer configured to combine signals
The circuit system includes intermediary components such as mixers configured to combine multiple sensor signal outputs for processing, enabling integration and normalization of sensor data from the multi-array system.
The independent claims delineate systems comprising a circuit base platform with arrays of ADFMR magnetic sensors, an oscillator input, and a circuit system configured for selective sensor activation with intermediary components including mixers. The claims include inventive features enabling time and frequency multiplexing, low power operation with triggers, passive and active shielding components, flexible sensor arrangements, and signal combination methods to provide efficient, sensitive multi-dimensional magnetic field sensing.
Stated Advantages
Low power usage enabling more mobile and less power-reliant sensing devices.
Noise cancellation and reduced need for heavy shielding, potentially allowing operation in less controlled environments.
Highly sensitive magnetic field measurements with range over several orders of magnitude, including low field strengths down to 1 fT.
High spatial resolution and multidimensional field measurements through dense sensor arrays with configurable sensor orientations and placements.
Cost-effective sensing arrays via sharing of expensive components among multiple sensors, reducing component count and package size.
Compact system form factors, enabling integration on chips or circuit boards suitable for wearable devices.
Flexible operational modes, including low power operation with triggers and active noise reduction modes.
Ability to implement as application specific integrated circuits (ASIC) or application-specific standard project (ASSP) chips for specialized or generalized implementations.
Documented Applications
Medical fields such as nuclear medicine, MRI, fMRI, brain activity monitoring, heart and muscle monitoring, sleep monitoring, emotion and brain-computer interfaces.
Augmented reality and virtual reality applications including positioning tools, accelerometers, head positioning, and incorporation into AR glasses, VR headsets, smart watches, chest straps, and fitness trackers.
General sensing technologies including functional near-infrared spectroscopy (fNIR), lidar, impedance tomography, and other magnetic sensing applications.
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