Magnetic field sensor based on amorphous wire giant magneto-impedance effect

Abstract

The invention provides a magnetic field sensor based on an amorphous wire giant magneto-impedance effect, which relates to the technical field of magnetic field testing and comprises a sensitive element module, an excitation module, a signal processing module and an anti-interference module. The sensitive element module adopts a CoFeSiB amorphous wire as a core sensitive material, an enameled wire is uniformly wound on the periphery of the amorphous wire to form an inductance coil, and the giant magneto-impedance effect of the amorphous wire is converted into a voltage signal through the inductance coil; and the excitation module is used for generating and outputting a high-frequency alternating excitation signal and loading the excitation signal to two ends of the inductance coil, so that the amorphous wire generates impedance change related to the to-be-measured magnetic field intensity under the action of high-frequency current. Through modular design and multi-technology cooperation of an amorphous wire giant magneto-impedance effect, Wheatstone bridge anti-interference, a temperature compensation algorithm, a multi-layer close winding and impedance matching technology, the performance bottlenecks of a traditional magnetic field sensor in the aspects of sensitivity, anti-interference, temperature drift control and signal transmission efficiency are broken through. And high-precision and high-reliability wide-temperature-range magnetic field detection is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic field testing, and particularly relates to a magnetic field sensor based on amorphous wire giant magnetoimpedance effect. BACKGROUND

[0002] The magnetic field sensor is a key device for converting magnetic field and its change into an electric signal, and has a wide application prospect in the fields of biomedicine, industrial detection, geological exploration, etc. In nature, the geomagnetic field distribution, the weak magnetic signal of a living body (such as the heart magnetic field and the brain magnetic field), and the magnetic leakage phenomenon of industrial equipment all need to be perceived and quantified through a high-precision magnetic field sensor.

[0003] The traditional magnetic field sensor (such as a Hall sensor and a fluxgate sensor) has significant limitations in practical application: the Hall sensor is limited by material properties, and has insufficient response to a weak magnetic field of nT level and is easily affected by temperature drift; the fluxgate sensor has high sensitivity, but has a complex structure and high power consumption, and is difficult to meet the requirements of miniaturization and low power consumption.

[0004] The amorphous wire material has potential in weak magnetic field detection due to its excellent magnetoimpedance effect, but how to efficiently convert the impedance change into an electric signal and suppress environmental noise and temperature drift is still a technical difficulty. Therefore, the present application provides a magnetic field sensor based on amorphous wire giant magnetoimpedance effect through modular design and hardware algorithm cooperation to solve the above technical problems. SUMMARY

[0005] The present application provides a magnetic field sensor based on amorphous wire giant magnetoimpedance effect to solve the problems proposed in the background.

[0006] To solve the above technical problems, the present application provides a magnetic field sensor based on amorphous wire giant magnetoimpedance effect, which comprises a sensitive element module, an excitation module, a signal processing module and an anti-interference module. The sensitive element module adopts CoFeSiB amorphous wire as a core sensitive material, and the amorphous wire is uniformly wound with an enameled wire to form an inductor coil, and the giant magnetoimpedance effect of the amorphous wire is converted into a voltage signal through the inductor coil. The excitation module is used for generating and outputting a high-frequency alternating excitation signal, and the excitation signal is loaded to both ends of the inductor coil, so that the amorphous wire generates impedance change related to the magnetic field strength to be measured under the action of the high-frequency current. The signal processing module is used for filtering, amplifying and analog-digital converting the voltage signal of the inductor coil. The anti-interference module adopts a differential bridge structure to suppress common-mode noise.

[0007] As a preferred, the excitation module comprises a signal generator, a power amplifier and a field effect transistor switching circuit. The signal generator is used for generating high-frequency alternating signals of specific frequency and phase; The power amplifier is used for amplifying the signal amplitude output by the signal generator; The field effect transistor switch circuit is used for controlling the on-off of the excitation signal and loading to both ends of the inductor coil.

[0008] As preferred, the signal processing module comprises a low-pass filter circuit, an amplification circuit and an analog-digital conversion circuit; The low-pass filter circuit is used for filtering high-frequency noise in the voltage signal and retaining low-frequency modulation signals reflecting the change of the magnetic field; The amplification circuit is used for gain amplification of the filtered signal, so as to improve the signal-to-noise ratio of the signal; The analog-digital conversion circuit is used for converting the amplified analog signal into a digital signal.

[0009] As preferred, the anti-interference module specifically adopts a bridge structure of four inductor coils in series: The four inductor coils are divided into two groups, two coils in the same axial direction are a group, and the other two coils in the other axial direction are another group, the number of turns, size and magnetic circuit distribution of the two groups of coils are completely symmetrical, forming a Wheatstone bridge structure, and the common-mode noise interference is offset through the use of the differential principle, specifically as follows: When the external common-mode noise magnetic field causes the impedance of each group of coils to be , the control bridge output voltage is obtained, and the expression of the bridge output voltage is: Wherein, represents the excitation voltage loaded to both ends of the diagonal line of the bridge, represents the initial impedance of the coil, and the coil impedance change caused by the external common-mode noise magnetic field.

[0010] As preferred, the application further comprises a temperature compensation module, which monitors the temperature in real time through an integrated thermistor, and adopts a linear compensation algorithm, including the following steps: The temperature is sensed in real time through the thermistor integrated in the sensor, and the resistance value of the thermistor satisfies , wherein is the resistance value at temperature , and B is the constant of the thermistor material; According to the linear relationship between the temperature and the output deviation of the sensor, the compensation voltage is calculated by the formula , wherein k is the temperature coefficient, is the reference temperature value; The calculated compensation voltage is operated with the sensor original output voltage to obtain the compensated output voltage , and the operation formula is .

[0011] As preferred, the amorphous wire is subjected to annealing treatment, and the annealing methods include conventional annealing, joule heat annealing, stress annealing or magnetic field annealing.

[0012] As preferred, the process of converting the amorphous wire giant magneto impedance effect into voltage signal by the inductive coil includes: loading high-frequency alternating signal to the inductive coil to make the amorphous wire generate skin effect, and the skin depth formula is: , wherein is the resistivity of the amorphous wire, is the permeability of the amorphous wire, and f is the excitation frequency; using the inductive reactance characteristics of the inductive coil, converting the impedance change amount of the amorphous wire into the voltage change amount across the two ends of the coil, and the formula is , wherein is the effective value of the excitation current, is the excitation voltage amplitude, is the initial impedance of the amorphous wire.

[0013] As preferred, the inductive coil adopts multi-layer dense winding process, and an insulating film is arranged between the layers, and an impedance matching network is integrated at the two ends of the coil; The impedance matching network is composed of adjustable capacitance and resistance, and the coil impedance is matched with the output impedance of the excitation module by adjusting the parameters of the matching network: The network analyzer is used to measure the inductive coil impedance and the output impedance of the excitation module , and according to the matching formula , the values of the adjustable capacitance and resistance are calculated and adjusted to match the impedances of the two; wherein, in the matching process, the total impedance of the inductive coil is changed by the adjustable capacitance C and the resistance R, wherein the inductive coil reactance , according to and , the impedance matching is satisfied and , wherein w is the angular frequency of the excitation signal, L is the inductance, is the distributed capacitance.

[0014] As preferred, the temperature coefficient k is determined by the following experiment: The difference between the measured sensor output voltage at different temperatures and the output voltage at the reference temperature is obtained, a linear relationship between the temperature and the output voltage deviation is fitted, the slope of the linear relationship is the temperature coefficient k, and the compensated sensor output error is not more than ± , The set temperature error threshold.

[0015] Compared with the related art, the magnetic field sensor based on the giant magnetoimpedance effect of amorphous wire provided by the application has the following beneficial effects: 1. The application utilizes the giant magnetoimpedance effect of CoFeSiB amorphous wire, combines the skin effect generated by high-frequency excitation, converts weak magnetic field changes into significant impedance changes, and then efficiently converts the voltage signal through the inductor coil, filters, amplifies and digitizes through the signal processing module, to realize accurate detection of nanotesla-level weak magnetic fields.

[0016] 2. The application uses a Wheatstone bridge structure through the anti-interference module, and through the differential principle of symmetrical inductor coils, the impedance changes caused by common-mode noise are mutually offset in the bridge output, effectively suppressing environmental electromagnetic interference and ensuring the purity of the detection signal, and improving the reliability in complex electromagnetic environments.

[0017] 3. The application sets a temperature compensation module, integrates a thermistor to monitor the temperature in real time, combines a linear compensation algorithm to calculate and correct the temperature drift, solves the problem of precision decline of traditional sensors caused by temperature fluctuations, and widens the application environment adaptability.

[0018] 4. The inductor coil of the application adopts a multi-layer dense winding process and sets an insulating film, improves the inductance while ensuring the insulation performance, integrates an adjustable impedance matching network at both ends, optimizes the excitation signal energy transmission through the conjugate matching principle, and reduces the reflection loss.

[0019] In summary, the application breaks through the performance bottleneck of traditional magnetic field sensors in sensitivity, anti-interference, temperature drift control and signal transmission efficiency through the modular design and multi-technology cooperation of the amorphous wire giant magnetoimpedance effect, Wheatstone bridge anti-interference, temperature compensation algorithm, multi-layer dense winding and impedance matching process, and realizes high-precision, high-reliability wide-temperature-range magnetic field detection. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The principle framework diagram of the magnetic field sensor based on the giant magnetoimpedance effect of amorphous wire provided by the application. DETAILED DESCRIPTION

[0021] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0022] The terms used in the present disclosure are merely for the purpose of describing particular embodiments and are not intended to limit the present disclosure. The singular forms "a," "an," and "the" used in the present disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0023] It should be understood that although the terms first, second, third, etc. can be used in this disclosure to describe various information, these information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon determination" or "in response to determining".

[0024] Please refer to Figure 1 The magnetic field sensor based on amorphous wire giant magnetoimpedance effect comprises a sensitive element module, an excitation module, a signal processing module and an anti-interference module. The sensitive element module adopts CoFeSiB amorphous wire as the core sensitive material, and the amorphous wire is uniformly wound with enameled wire to form an inductor coil, and the giant magnetoimpedance effect of the amorphous wire is converted into a voltage signal through the inductor coil. The excitation module is used for generating and outputting a high-frequency alternating excitation signal, and the excitation signal is loaded to both ends of the inductor coil, so that the amorphous wire generates impedance change related to the magnetic field strength to be measured under the action of high-frequency current. The signal processing module is used for filtering, amplifying and analog-to-digital converting the voltage signal of the inductor coil to extract the effective signal. The anti-interference module adopts a differential bridge structure to suppress common-mode noise, so as to ensure the accuracy and reliability of the detection signal.

[0025] Specifically, the excitation module comprises a signal generator, a power amplifier and a field effect transistor switch circuit. The signal generator is used for generating a high-frequency alternating signal with a specific frequency and phase. The power amplifier is used for amplifying the signal amplitude output by the signal generator. The field effect transistor switch circuit is used for controlling the on-off of the excitation signal and loading to the inductor coil.

[0026] It should be noted that the excitation module realizes high-frequency excitation of the inductor coil through the cooperation of the signal generator, the power amplifier and the field effect transistor switch circuit: the signal generator provides a high-frequency alternating signal with a specific frequency and phase as an excitation source; the power amplifier amplifies the amplitude of the signal to ensure that the excitation energy is sufficient to drive the amorphous wire to produce significant giant magnetoimpedance effect; and the field effect transistor switch circuit is responsible for controlling the on-off of the excitation signal and accurately loading the amplified signal to both ends of the inductor coil, so that the amorphous wire produces impedance changes related to the measured magnetic field strength under the action of high-frequency current, providing effective input for subsequent signal processing.

[0027] Specifically, the signal processing module includes a low-pass filter circuit, an amplification circuit and an analog-to-digital conversion circuit. The low-pass filter circuit is used for filtering high-frequency noise in the voltage signal and retaining low-frequency modulated signals reflecting changes in the magnetic field. The amplification circuit is used for gain amplification of the filtered signal to improve the signal-to-noise ratio of the signal. The analog-to-digital conversion circuit is used for converting the amplified analog signal into a digital signal.

[0028] It should be noted that the signal processing module realizes signal optimization through the cooperation of three circuits: the low-pass filter circuit uses the frequency selection characteristic of the RC network to filter high-frequency noise (such as 60 kHz carrier) caused by the excitation signal and only retains low-frequency signals (usually <1 kHz) related to changes in the magnetic field; the amplification circuit adopts an instrument amplifier structure to amplify the gain of the filtered weak signal by adjusting the proportion of the feedback resistor to improve the signal strength to match the subsequent analog-to-digital conversion requirements; and the analog-to-digital conversion circuit (such as 16-bit ADC) converts the amplified analog signal into a digital signal with quantization precision, which is convenient for embedded systems or host computers to perform digital filtering, algorithm solving and other processing, and finally realizes accurate quantization of the magnetic field strength.

[0029] Specifically, the anti-interference module specifically adopts a bridge structure with four inductor coils connected in series. The four inductor coils are divided into two groups, two coils in the same axial direction form a group, and the other two coils in the other axial direction form another group. The number of turns, size and magnetic path distribution of the two groups of coils are completely symmetrical, forming a Wheatstone bridge structure, and the common-mode noise interference is offset through the use of the differential principle, specifically as follows: When the external common-mode noise magnetic field causes the impedance of each group of coils to change to , the control bridge output voltage , and the expression of the bridge output voltage is: wherein, represents the excitation voltage loaded to both ends of the diagonal of the bridge, represents the initial impedance of the coil, represents the coil impedance change amount caused by the external common-mode noise magnetic field.

[0030] It should be noted that in the scenario of using a Wheatstone bridge structure to offset common-mode noise interference, the expression of the bridge output voltage is used to calculate the output voltage of the bridge. When the external common-mode noise magnetic field uniformly acts on the coils in the bridge, due to the symmetrical structure design of the bridge, the coils at the symmetrical positions (such as ) will produce the same impedance change (both change to ), and the calculation by the formula shows that the output voltage of the bridge is 0 at this time, indicating that the common-mode noise signals cancel each other out in the bridge with this symmetrical structure, and the common-mode noise is eliminated from the hardware level, ensuring that the bridge output signal does not contain common-mode noise components, thereby improving the accuracy and reliability of the magnetic field sensor in detecting the measured magnetic field signal.

[0031] Specifically, the application also includes a temperature compensation module, which monitors the temperature in real time through an integrated thermistor, and uses a linear compensation algorithm, including the following steps: The temperature is sensed in real time by a thermistor integrated in the sensor, and the resistance value of the thermistor satisfies , where is the resistance value at temperature , and B is the constant of the thermistor material; According to the linear relationship between temperature and sensor output deviation, the compensation voltage is calculated by the formula , where k is the temperature coefficient, is the reference temperature value; The calculated compensation voltage is operated with the original output voltage of the sensor to obtain the compensated output voltage , and the operation formula is .

[0032] It should be noted that the temperature compensation module corrects the temperature drift by combining hardware and algorithm: the integrated thermistor is used to monitor the ambient temperature in real time, and the current temperature value is inversely calculated based on the nonlinear relationship between the resistance value and the temperature ( ); the output deviation compensation amount caused by temperature change is calculated by a linear compensation algorithm ( ), where the temperature coefficient k is calibrated by experiment; finally, the compensation voltage and the original output voltage are operated ( ), eliminate the influence of temperature on the sensor accuracy, and ensure the stability of the detection results in a wide temperature range environment.

[0033] Specifically, the amorphous wire is subjected to annealing treatment, and the annealing methods include conventional annealing, joule heat annealing, stress annealing or magnetic field annealing.

[0034] Specifically, the process of converting the giant magneto-impedance effect of the amorphous wire into a voltage signal by the inductor coil includes: The high-frequency alternating signal is loaded to the inductor coil to make the amorphous wire generate skin effect, and the skin depth formula of the amorphous wire is: , wherein is the resistivity of the amorphous wire, is the permeability of the amorphous wire, and f is the excitation frequency, which determines the penetration depth of the current on the surface of the amorphous wire together. The skin depth and the current distribution are affected by the external magnetic field, thereby causing the impedance Z of the amorphous wire to change; The inductive reactance characteristic of the inductor coil is used to convert the impedance change amount of the amorphous wire into the voltage change amount across the two ends of the coil, and the formula is , wherein is the effective value of the excitation current, is the amplitude of the excitation voltage, is the initial impedance of the amorphous wire, and the impedance change amount of the amorphous wire is determined by the difference between the voltage signals across the two ends of the inductor coil at different collection times. The quantitative relationship between the electrical signal and the impedance change is established by the formula, and the impedance change amount of the amorphous wire is determined by the difference between the voltage signals across the two ends of the inductor coil at different collection times, so as to accurately convert the impedance effect corresponding to the change of the magnetic field into a measurable voltage signal.

[0035] Specifically, the inductor coil adopts a multi-layer dense winding process, an insulating film is arranged between the layers, and an impedance matching network is integrated at the two ends of the coil. It should be noted that the inductance value L of the coil is proportional to the permeability of the amorphous wire, and the formula is: , wherein is the vacuum permeability, A is the cross-sectional area of the coil, and l is the length of the coil. The impedance matching network is composed of an adjustable capacitor and a resistor, and the impedance of the coil is matched with the output impedance of the excitation module by adjusting the parameters of the matching network: The impedance of the inductor coil and the output impedance of the excitation module are measured by using a network analyzer, and according to the conjugate matching principle, the matching formula is calculated, and the values of the adjustable capacitor and the resistor are adjusted to match the impedances of the two. Wherein, in the matching process, the total impedance of the inductive coil is changed by the adjustable capacitor C and the resistor R, wherein the inductive coil reactance , according to and , meet and The impedance matching is realized, wherein w is the angular frequency of the excitation signal, L is the inductance of the coil, is the distributed capacitance; by changing the adjustable capacitor C and the resistor R, the total impedance is adjusted, so that the excitation signal energy can be transmitted to the coil to the maximum, and the reflection loss is reduced.

[0036] Specifically, the temperature coefficient k is determined by the following experiment: The difference between the measured sensor output voltage at different temperatures and the output voltage at the reference temperature is obtained, and the linear relationship between the temperature and the output voltage deviation is fitted, and the slope of the linear relationship is the temperature coefficient k, and in the temperature range [Tmin, Tmax], the output error of the compensated sensor is not more than ± , is the set temperature error threshold, so as to realize the accurate correction of temperature drift and guarantee the measurement accuracy of the sensor in the wide temperature environment.

[0037] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice in the art to which the application pertains. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0038] It should be understood that the application is not limited to the precise construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the application is limited only by the claims that follow.

Claims

1. A magnetic field sensor based on the giant magnetoimpedance effect in amorphous wires, characterized in that, The sensitive element module, the excitation module, the signal processing module and the anti-interference module are included. The CoFeSiB amorphous wire is used as the core sensitive material in the sensitive element module, and the amorphous wire is uniformly wound with the enameled wire to form an inductor coil, and the giant magneto-impedance effect of the amorphous wire is converted into a voltage signal through the inductor coil. The excitation module is used for generating and outputting a high-frequency alternating excitation signal, and the excitation signal is loaded to both ends of the inductor coil, so that the amorphous wire generates impedance changes related to the measured magnetic field strength under the action of the high-frequency current. The signal processing module is used for filtering, amplifying and analog-digital converting the voltage signal of the inductor coil. The anti-interference module adopts a differential bridge structure to suppress common-mode noise.

2. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, The excitation module includes a signal generator, a power amplifier and a field effect transistor switch circuit. The signal generator is used for generating a high-frequency alternating signal with a specific frequency and phase. The power amplifier is used for amplifying the signal amplitude output by the signal generator. The field effect transistor switch circuit is used for controlling the on-off of the excitation signal and loading to both ends of the inductor coil.

3. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, The signal processing module includes a low-pass filter circuit, an amplifier circuit and an analog-digital conversion circuit. The low-pass filter circuit is used for filtering high-frequency noise in the voltage signal and retaining low-frequency modulated signals reflecting the change of the magnetic field. The amplifier circuit is used for gain amplifying the filtered signal to improve the signal-to-noise ratio of the signal. The analog-digital conversion circuit is used for converting the amplified analog signal into a digital signal.

4. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, The anti-interference module specifically adopts a bridge structure with four inductor coils connected in series. The four inductance coils are divided into two groups, two coils in the same axial direction form a group, and the other two coils in the other axial direction form another group, the number of turns, size and magnetic circuit distribution of the two groups of coils are completely symmetrical, forming a Wheatstone bridge structure, and the common mode noise interference is offset by adopting the differential principle, specifically: When the external common-mode noise magnetic field causes the impedances of all the groups of coils to become , the control bridge outputs a voltage , and the expression of the bridge output voltage is: , wherein represents the excitation voltage loaded to both ends of the diagonal line of the bridge, represents the initial impedance of the coil, represents the coil impedance variation amount caused by the external common-mode noise magnetic field.

5. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, It also includes a temperature compensation module, which monitors the temperature in real time by integrating a thermistor and uses a linear compensation algorithm, including the following steps: The temperature is sensed in real time by a thermistor integrated inside the sensor, the resistance value of the thermistor satisfies the temperature T , wherein is the resistance value of the thermistor at the temperature T , and B is a constant of the thermistor material. According to the linear relationship between temperature and sensor output deviation, the compensation voltage is calculated by the formula where k is the temperature coefficient, is the reference temperature value.​ The calculated compensation voltage is operated with the sensor original output voltage to obtain the compensated output voltage , and the operation formula is .

6. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, The amorphous wire is annealed, and the annealing methods include conventional annealing, joule heat annealing, stress annealing or magnetic field annealing.

7. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, The process of converting the giant magneto-impedance effect of the amorphous wire into a voltage signal by the inductor coil includes: The high-frequency alternating signal is loaded to the inductive coil, so that the amorphous wire generates skin effect, and a skin depth formula of the amorphous wire is: Wherein is the resistivity of the amorphous wire, is the magnetic permeability of the amorphous wire, and f is an excitation frequency. The inductive characteristic of the inductor coil is used to convert the impedance change of the amorphous wire into the voltage change at both ends of the coil The formula is Wherein is the effective value of the excitation current, is the amplitude of the excitation voltage, is the initial impedance of the amorphous wire.​ 8. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 1, characterized in that, The inductor coil adopts a multi-layer dense winding process, and an insulating film is arranged between the layers, and an impedance matching network is integrated at both ends of the coil. The impedance matching network is composed of adjustable capacitors and resistors, and the coil impedance is matched with the output impedance of the excitation module by adjusting the matching network parameters: Measuring inductance coil impedance using a network analyzer and the excitation module output impedance , according to the matching formula the values of the adjustable capacitance and resistance are calculated and adjusted so that both impedances match; wherein during the matching process the total impedance of the inductive coil is varied by means of an adjustable capacitor C and a resistor R, wherein the inductive coil has an inductive reactance , according to and satisfies and the impedance matching is achieved, wherein w is the angular frequency of the excitation signal, L is the inductance, is the distributed capacitance.

9. The magnetic field sensor based on amorphous wire giant magnetoimpedance effect according to claim 5, characterized in that, The temperature coefficient k is determined through the following experiment: The difference between the measured sensor output voltage at different temperatures and the output voltage at the reference temperature is obtained, and a linear relationship between the temperature and the output voltage deviation is fitted. The slope of the linear relationship is the temperature coefficient k, and the compensated sensor output error is not more than ± , is the set temperature error threshold.

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