GSR Micro Magnetometer with Compensation Coil for High Sensitivity
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Solution Overview
Problem
Current high-sensitive micro-sized magnetometers face challenges in achieving ultra-high sensitivity and wide measuring ranges while maintaining low current consumption and small size, particularly due to issues with coil voltage drop-off at high frequencies and increased parasitic capacitance.
Innovation Solution
The development of a GSR sensor utilizing glass-coated amorphous wires with high permeability and micro-coils, operating with pulse frequencies between 0.5 GHz and 4 GHz, which enhances coil voltage detection through spin rotation effects and minimizes noise and parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse frequency is increased to improve sensitivity, then sensitivity is improved, but coil voltage drops and parasitic capacitance increases
Solution Approach 1:
The patent applies parameter changes by optimizing the pulse frequency to a specific range (0.5-4 GHz) where the spin rotation effect is maximized while minimizing parasitic capacitance effects. It also changes material parameters by using glass-coated amorphous wires with specific permeability characteristics to maintain coil voltage at high frequencies.
2Measurement precision
If pulse frequency is increased to improve sensitivity, then sensitivity is improved, but parasitic capacitance increases causing noise
Solution Approach 1:
The patent changes the operating frequency parameter to the 0.5-4 GHz range where spin rotation effect dominates over parasitic capacitance effects. It also changes material parameters by using glass-coated amorphous wires that maintain magnetic properties while reducing parasitic capacitance at high frequencies.
3Length of moving object
If wire length is decreased to reduce size, then size is reduced, but sensitivity decreases
Solution Approach 1:
The patent changes the operating frequency parameter to GHz range where the spin rotation effect provides high sensitivity even for short wire lengths. It also changes material parameters by using glass-coated amorphous wires with high permeability to compensate for the reduced length effect.
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 GSR sensor achieves significantly improved performance, offering 100 times higher sensitivity and wider measuring ranges compared to commercial MI sensors, with reduced noise and current consumption, suitable for applications like indoor navigation and wearable computers.
Implementation Method 1
GSR sensor based on spin rotation effect with ultra-high speed powered by GHz pulse current
Implementation Method 2
The longitudinal magnetization of the wire is lowered by the diamagnetic field inverse proportional to the wire length. It is difficult to decrease the wire length without the decrease of the sensor sensitivity
Implementation Method 3
The magneto-impedance of the wire is drastically increased dependent on the external magnetic field due to the skin effect induced by high frequency current
Implementation Method 4
The influence of the frequency on the magneto-impedance shows it has a maximum value at 10 MHz and decreases beyond 10 MHz due to eddy current increased proportional to frequency
Data Source
AI summary
The magnetometers possess detector part with a magnetic wire sensitive to magnetic field consisting of a domain structure of the surface domain with circular spin alignment and core domain with longitudinal spin alignment and micro coil surrounding its magnetic wire to pick up the change of longitudinal magnetizing caused by spin rotation in surface domain with circular spin alignment called as GSR effect excited by pulse with frequency of 0.5 GHz to 4 GHz. Peak coil voltage is detected by a circuit characterized with pulse generator, GSR element, Buffer circuit, sample holding circuit, amplifier circuit and means to invert it to external magnetic field. The induced coil voltage caused by parasitic coil capacitance and wiring loop is vanished by combination coil of right and left turn coil. The magnetometers can provide lower noise, wide measuring range with a small size detector part and is applied to smartphones, wearable computer and so on.