WO2023151130A1

WO2023151130A1 - Microwave magnetic sensor and measurement method therefor

Info

Publication number: WO2023151130A1
Application number: PCT/CN2022/077536
Authority: WO
Inventors: 维尼·辛格; 陈林峰; 陈锦华; 潘峰; 魏锦烨; 李敏; 韩文都
Original assignee: 湖州久鼎电子有限公司
Priority date: 2022-02-10
Filing date: 2022-02-23
Publication date: 2023-08-17
Also published as: CN114779133A

Abstract

A microwave magnetic sensor, comprising two half-wavelength resonators (1) and a magnetoresistive element (2), wherein each half-wavelength resonator (1) is a transmission line; the length of each half-wavelength resonator is equal to half of the wavelength corresponding to a fundamental mode resonant frequency f0 of the half-wavelength resonator; the two half-wavelength resonators have the same length and the same fundamental mode resonant frequency f0; the magnetoresistive element (2) is located between the two half-wavelength resonators (1) and is symmetrically spaced apart from the two half-wavelength resonators (1) at equal intervals; the magnetoresistive element (2) and end portions of the two half-wavelength resonators (1) form a coupling capacitor CAP; and the two half-wavelength resonators (1) are coupled by means of the coupling capacitor CAP. By means of the microwave magnetic sensor, an external magnetic field is determined according to a change in a first resonant frequency of the microwave magnetic sensor. The resonant frequency of a resonant structure can be accurately measured, such that the microwave magnetic sensor has higher sensitivity and accuracy than existing magnetoresistive sensors based on a Wheatstone bridge.

Description

A microwave magnetic sensor and its measuring method

technical field

The invention relates to the field of sensors, in particular to a microwave magnetic sensor and a measuring method thereof.

Background technique

Magnetic sensors are widely used in consumer electronics and industrial production, especially magnetic sensors are playing an increasingly important role in the Internet of Things (IoT) and Industrial Internet of Things (IIoT). Magnetic sensors can be used to provide smart home solutions, for example, allowing users to turn appliances on and off remotely and adjust energy consumption in real time by measuring current and voltage. Magnetic sensors can also be used to provide angle sensing, distance sensing, motion sensing, and safety switches for robotics and factory automation.

Magnetic sensors with magnetoresistive (MR) elements have been used on a large scale. The resistance of a magneto-resistive element changes as the external magnetic field experienced by the magneto-resistive element changes. The magnetoresistance elements include semiconductor magnetoresistance elements such as indium antimonide (InSb) and metal magnetoresistance elements such as giant magnetoresistance (GMR) elements, tunnel magnetoresistance (TMR) elements, and anisotropic magnetoresistance (AMR) elements. Magnetic sensors with metal magnetoresistive elements are widely favored mainly due to their advantages in sensitivity and reliability.

However, since the metal magnetoresistive element itself is a conductor, it is difficult to accurately measure the change of the resistivity of the metal magnetoresistive element. Therefore, the sensitivity and accuracy of the magnetic sensor with metal magnetoresistive elements need to be further improved.

Contents of the invention

The object of the present invention is to provide a microwave magnetic sensor to solve the problems raised in the background art.

The technical solution of the present invention is: a kind of microwave magnetic sensor, comprises:

Two half-wavelength resonators, each of the half-wavelength resonators is a section of transmission line whose length is equal to half of the wavelength corresponding to its fundamental mode resonance frequency, and the two half-wavelength resonators have the same length and the same Fundamental mode resonant frequency;

A magneto-resistance element, the magneto-resistance element is located between the two half-wavelength resonators, and is equidistantly and symmetrically spaced from the two half-wavelength resonators, and the magneto-resistance element resonates with the two half-wavelength resonators The ends of the resonators constitute coupling capacitors through which the two half-wavelength resonators are coupled.

Preferably, the magneto-resistance element is a metal magneto-resistance element, including a giant magneto-resistance element, a tunnel magneto-resistance element or an anisotropic magneto-resistance element.

Preferably, the transmission line is a planar transmission line, including stripline, microstrip or coplanar line.

Preferably, said transmission line is a microstrip.

Preferably, the substrate is made of low-loss dielectric materials, including but not limited to silicon, gallium arsenide, FR-4, alumina, sapphire, quartz or combinations thereof;

Ground wire, made of highly conductive metals, including but not limited to gold, silver, copper, or combinations thereof.

Preferably, the protective layer covers the magnetoresistive element;

The protective layer is made of low-k materials, including but not limited to fluorine-doped silica, silicone glass, porous silica or combinations thereof.

Preferably, the protective layer fills a gap between the resonator and the magnetoresistive element, and covers a part of the half-wavelength resonator.

Preferably, the magnetoresistive element has a stepped structure on each side;

The magnetoresistive element includes a top surface, a middle surface and a bottom surface, the bottom surface of the magnetoresistive element directly contacts the top surface of the substrate, and the middle surface and the top surface of the magnetoresistive element are located on the top surface of the half-wavelength resonator above, and cover part of the half-wavelength resonator on each side.

Preferably, the isolation element is arranged between the half-wavelength resonator and the magnetoresistive element;

The isolation element has a stepped structure;

The isolation element includes a top surface, a middle surface and a bottom surface, the top surface of the isolation element directly contacts the middle surface of the magnetoresistive element, and the middle surface of the isolation element directly contacts the top surface of the half-wavelength resonator, The bottom surface of the isolation element is directly on the top surface of the contact substrate.

The isolation elements are made of low-k materials including, but not limited to, fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

Preferably, the protective layer covers the magnetoresistive element;

The protective layer is made of low-k materials, including but not limited to fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

Preferably, said spacer element has a stepped structure on each side;

The isolation element includes a top surface, a middle surface and a bottom surface, the bottom surface of the isolation element directly contacts the top surface of the substrate, the middle surface of the isolation element directly contacts the top surface of the half-wavelength resonator, and in each The side covers a part of the half-wavelength resonator, and the magnetoresistive element is arranged on the top surface of the isolation element;

The material of the isolation element is a low-k material, including but not limited to fluorine-doped silicon dioxide, organic silicon glass, porous silicon dioxide or a combination thereof.

Preferably, the protective layer covers the magnetoresistive element;

Preferably, the half-wavelength resonator includes a transition portion, and the transition portion is located on a side of the half-wavelength resonator close to the magnetoresistive element;

The width of an end of the transition portion close to the magnetoresistive element is consistent with the width of the magnetoresistive element.

Preferably, the coupling unit is used to measure the resonant frequency of the microwave magnetic sensor;

The coupling unit is made of a length of transmission line whose characteristic impedance is identical to that of the external measurement line.

Preferably, the coupling between the coupling unit and the half-wavelength resonator is end-to-end coupling.

Preferably, the coupling between the coupling unit and the half-wavelength resonator is parallel coupling.

Preferably, the substrate, the half-wavelength resonator, the coupling unit and the ground wire are made of non-magnetic materials.

A measuring method of a microwave magnetic sensor, comprising:

S1, obtain the calibration curve between the first resonant frequency of the microwave magnetic sensor and the external magnetic field strength, the first resonant frequency is the lowest resonant frequency of the microwave magnetic sensor, and the calibration curve is passed in the range of interest obtained by measuring the first resonant frequency of the microwave magnetic sensor under external magnetic fields of different strengths;

S2. Measure the first resonant frequency of the microwave magnetic sensor under the magnetic field to be measured, and obtain the strength of the magnetic field to be measured according to the calibration curve.

The beneficial effects of the present invention are:

Compared with the prior art, the microwave magnetic sensor provided by the present invention can determine the external magnetic field according to the change of the first resonant frequency of the microwave magnetic sensor. Since the resonant frequency of the resonant structure can be accurately measured, the microwave magnetic sensor provided by the invention has higher sensitivity and accuracy than the existing Wheatstone bridge-based reluctance sensor. Furthermore, the microwave magnetic sensor can be fabricated using conventional semiconductor fabrication processes and techniques. In addition, since microwave magnetic sensors work at microwave frequencies, microwave magnetic sensors can be integrated into wireless communication systems to achieve remote, wireless sensing.

Description of drawings

Fig. 1 is a schematic structural diagram of a microwave magnetic sensor provided by an embodiment of the present invention;

FIG. 2 is a partial enlarged view of the coupling capacitor CAP in FIG. 1;

Fig. 3 is a diagram of the relationship between the first resonant frequency of an exemplary microwave magnetic sensor and the resistivity of the magnetoresistive element provided by the embodiment of the present invention;

Fig. 4 is a top view of a microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 5 is a sectional view along A-A' section in Fig. 4;

6 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention;

7 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 8 is a top view of another microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 9 is a sectional view along B-B' section in Fig. 8;

Figure 10 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 11 is a top view of another microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 12 is a cross-sectional view along C-C' section in Fig. 11;

Fig. 13 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 14 is a top view of another microstrip magnetic sensor provided by an embodiment of the present invention;

Fig. 15 is a sectional view along D-D' section among Fig. 14;

Fig. 16 is a schematic structural diagram of another microwave magnetic sensor provided by an embodiment of the present invention.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of the exemplary embodiments is merely illustrative in nature and in no way is taken as any limitation of the invention and its application or uses. In all examples shown and discussed, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the description.

It should be noted that like numerals and letters denote like items in the figures, therefore, once an item is defined in one figure, it is not discussed further in subsequent figures.

As mentioned in the background, since the metal magnetoresistive element itself is a conductor, it is difficult to accurately measure the change of the resistivity of the metal magnetoresistive element. Therefore, the sensitivity and accuracy of the magnetic sensor with metal magnetoresistive elements need to be further improved.

In view of this, the present invention provides a microwave magnetic sensor with a metal magnetoresistance element and a measurement method thereof, which effectively solves the technical problems in the prior art and improves the sensitivity and accuracy of the magnetic sensor with a metal magnetoresistance element .

In the microwave magnetic sensor with metal magnetoresistive element provided by the present invention, when an external magnetic field is applied to the magnetoresistive element, the resistivity of the magnetoresistive element will change, so the resonance characteristic of the microwave magnetic sensor will also change. According to the change of the resonant characteristics of the microwave magnetic sensor, the strength of the external magnetic field can be obtained.

Fig. 1 is a schematic structural diagram of a microwave magnetic sensor provided by an embodiment of the present invention. As shown in FIG. 1 , the microwave magnetic sensor includes two half-wavelength resonators 1 and a magnetoresistive element 2 . Each of the half-wavelength resonators 1 is a section of transmission line whose length is equal to half of the wavelength corresponding to its fundamental-mode resonant frequency f ₀ . The two half-wavelength resonators have the same length and the same fundamental-mode resonance frequency f ₀ . The magneto-resistive element 2 is located between the two half-wavelength resonators 1 and is equidistantly and symmetrically spaced from the two half-wavelength resonators 1 . The magneto-resistive element 2 and the ends of the two half-wavelength resonators 1 form a coupling capacitor CAP, as shown by the dashed box in FIG. 1 . The two half-wavelength resonators 1 are coupled through the coupling capacitor CAP.

FIG. 2 is a partial enlarged view of the coupling capacitor CAP in FIG. 1 , including an equivalent circuit of the coupling capacitor CAP. As shown in FIG. 2 , the coupling capacitor CAP includes three capacitances, which are two capacitances C1 formed between the half-wavelength resonator 1 and the magnetoresistive element 2 , and a self-capacitance C2 of the magnetoresistive element 2 . The respective capacitances of the three capacitors are related to the resistivity of the magnetoresistive element 2 . Therefore, the total capacitance C of the coupling capacitor CAP is related to the resistivity of the magnetoresistive element 2 .

In the microwave magnetic sensor, since two half-wavelength resonators 1 are coupled through the coupling capacitor CAP, the fundamental mode resonance of the microwave magnetic sensor degenerates into two resonances, which have the first resonant frequency _f and the second resonant frequency f ₂ . The first resonant frequency f ₁ is lower than the fundamental-mode resonant frequency f ₀ of the half-wavelength resonator 1 , and the second resonant frequency f ₂ is higher than the fundamental-mode resonant frequency f ₀ of the half-wavelength resonator 1 . Specifically, the first resonance frequency is the lowest resonance frequency of the microwave magnetic sensor.

The difference between the first resonance frequency f ₁ and the second resonance frequency f ₂ is related to the total capacitance C of the coupling capacitor CAP. A change in the total capacitance C will result in a change in the first resonant frequency f ₁ and the second resonant frequency f ₂ . The total capacitance C can be calculated from the first resonant frequency _f1 and the second resonant frequency _f2 :

where _Z0 is the characteristic impedance of the transmission line making up the half-wavelength resonator. It can be understood that when the total capacitance C becomes larger, the difference between f ₁ and f ₂ will become larger, and the first resonant frequency f ₁ will decrease.

When the resistivity of the magnetoresistive element 2 decreases, the total capacitance C will increase, so the first resonant frequency f _l will decrease. Fig. 3 is a diagram of the relationship between the first resonant frequency of an exemplary microwave magnetic sensor and the resistivity of the magneto-resistive element according to an embodiment of the present invention. This exemplary microwave magnetic sensor is made of microstrip with a characteristic impedance of 50Ω. As shown in FIG. 3 , when the resistivity of the magnetoresistive element decreases, the first resonant frequency f ₁ of the exemplary microwave magnetic sensor decreases monotonously. Therefore, according to the first resonant frequency f ₁ , the resistivity of the magnetoresistive element can be deduced.

In the present invention, the coupling capacitor CAP includes the magnetoresistive element 2 . Magnetoresistance refers to the change in resistivity of a sample under an external magnetic field of strength H:

Wherein δH represents magnetoresistance, R(H) is the resistivity of the sample in a magnetic field with strength H, and R(0) is the resistivity of the sample when H=0.

The magnetoresistance element 2 in the present invention is a metal magnetoresistance element. The metal magnetoresistance element may be a giant magnetoresistance (GMR) element, a tunnel magnetoresistance (TMR) element or an anisotropic magnetoresistance (AMR) element. Generally, the δH value of the GMR element, the TMR element, and the AMR element is larger than that of the semiconductor magnetoresistive element. Taking GMR as an example, GMR is a spintronic effect, and the operation of GMR elements is based on the dependence of electron scattering on spin orientation. The thin-film structure of the GMR element consists of alternating ferromagnetic and non-magnetic conductive layers. Depending on the magnetization alignment of adjacent ferromagnetic layers, the overall resistivity of the thin-film structure can vary significantly. When arranged in parallel, the total resistivity is relatively low, while in antiparallel arrangement, the total resistivity is relatively high.

In the present invention, the transmission line used to make the half-wavelength resonator can be any type of planar transmission line, including stripline, microstrip and coplanar line. The following describes a microstrip as an exemplary planar transmission line.

Fig. 4 is a top view of a microstrip magnetic sensor provided by an embodiment of the present invention. Fig. 5 is a sectional view along section A-A' in Fig. 4 . As shown in FIG. 4 and FIG. 5 , the microstrip magnetic sensor includes two half-wavelength resonators 101 , a magnetoresistive element 102 , a substrate 103 and a ground wire 104 .

The two half-wavelength resonators 101 are made of highly conductive metals, including but not limited to gold, silver, copper or combinations thereof. The two half-wavelength resonators 101 may have a multi-layer structure.

The magnetoresistive element 102 is a metal magnetoresistive element, which may be one of a GMR element, a TMR element and an AMR element. The magnetoresistive element 102 is located between the two half-wavelength resonators 101, and is equidistantly and symmetrically spaced from the two half-wavelength resonators. The magnetoresistive element 102 may have a multilayer structure.

The substrate 103 is made of a low loss dielectric material including but not limited to silicon, gallium arsenide, FR-4, alumina, sapphire, quartz or combinations thereof.

The ground wire 104 is made of highly conductive metals, including but not limited to gold, silver, copper or combinations thereof. The ground wire may have a multilayer structure.

The magnetoresistive element 102 may be covered by a protective layer. Fig. 6 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention. As shown in FIG. 6 , in one embodiment, the magnetoresistive element 102 is covered by a protective layer 105 . The protection layer 105 is made of a low-k material, including but not limited to fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

In one embodiment, the magnetoresistive element 102 is covered by a protective layer that fills the gap between the resonator 101 and the magnetoresistive element 102 and covers a portion of the half-wavelength resonator 101 . Fig. 7 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention. As shown in FIG. 7 , the magnetoresistive element 102 is covered by a protective layer 106 , and the protective layer 106 fills the gap between the resonator 101 and the magnetoresistive element 102 and covers a part of the half-wavelength resonator 101 . The protective layer 106 is made of a low-k material including, but not limited to, fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

In the present invention, the coupling capacitor CAP may have various structures. Fig. 8 is a top view of another microstrip magnetic sensor provided by an embodiment of the present invention. Fig. 9 is a sectional view along section B-B' in Fig. 8 . As shown in FIGS. 8 and 9 , in one embodiment, the microstrip magnetic sensor includes a magnetoresistive element 202 and two isolation elements 207 .

The magnetoresistive element 202 has a stepped structure on each side. The magnetoresistive element 202 includes a top surface, a middle surface and a bottom surface. The bottom surface of the magnetoresistive element 202 directly contacts the top surface of the substrate 103 . The middle and top surfaces of the magneto-resistive element 202 are located above the top surface of the half-wavelength resonator 101 and cover a part of the half-wavelength resonator 101 on each side.

The isolation element 207 has a stepped structure. The isolation element 207 is provided between the half-wavelength resonator 101 and the magnetoresistive element 202 . The isolation element 207 includes a top surface, a middle surface and a bottom surface. The top surface of the isolation element 207 directly contacts the middle surface of the magnetoresistive element 202 , and the middle surface of the isolation element 207 directly contacts the top surface of the half-wavelength resonator 101 . The bottom surface of the isolation element 207 directly contacts the top surface of the substrate 103 . Isolation elements 207 are made of low-k materials including, but not limited to, fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

The magneto-resistive element 202 is a metal magneto-resistive element, which may be one of a GMR element, a TMR element and an AMR element. The magnetoresistive element 202 may have a multilayer structure.

In one embodiment, the magnetoresistive element is covered by a protective layer. Fig. 10 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention. As shown in FIG. 10 , the magnetoresistive element 202 is covered by a protective layer 205 . The protection layer 205 is made of a low-k material, including but not limited to fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

In one embodiment, the materials of the isolation element 207 and the protection layer 205 are the same. In some other embodiments, the isolation element 207 and the protective layer 205 may be made of different materials.

Fig. 11 is a top view of another microstrip magnetic sensor provided by an embodiment of the present invention. Fig. 12 is a cross-sectional view along section C-C' in Fig. 11. As shown in FIGS. 11 and 12 , in one embodiment, the magnetic sensor includes a magnetoresistive element 302 and an isolation element 307 .

The isolation element 307 has a stepped structure on each side. The isolation element 307 includes a top surface, a middle surface and a bottom surface. The bottom surface of the isolation element 307 directly contacts the top surface of the substrate 103 . The middle face of the isolation element 307 directly touches the top face of the half-wave resonator 101 and covers a part of the half-wave resonator 101 on each side. The magnetoresistive element 302 is disposed on the top surface of the isolation element 307 . The material of the isolation element 307 is a low-k material, including but not limited to fluorine-doped silicon dioxide, organic silicon glass, porous silicon dioxide or a combination thereof.

In one embodiment, the magnetoresistive element 302 is covered by a protective layer. Fig. 13 is a cross-sectional view of another microstrip magnetic sensor provided by an embodiment of the present invention. As shown in FIG. 13 , the magnetoresistive element 302 is covered by a protective layer 305 . The protection layer 305 is made of a low-k material, including but not limited to fluorine-doped silica, silicone glass, porous silica, or combinations thereof.

In one embodiment, the isolation element 307 and the protective layer 305 are made of the same material. In some other embodiments, the isolation element 307 and the protective layer 305 may be made of different materials.

In the present invention, the width of the end of the half-wavelength resonator close to the magnetoresistive element can be adjusted to meet specific measurement requirements. In an embodiment, the half-wavelength resonator includes a transition portion, and the transition portion is located on a side of the half-wavelength resonator close to the magnetoresistive element. Through the transition part, the width of the end of the half-wavelength resonator close to the magnetoresistive element can be consistent with the width of the magnetoresistive element, so as to meet specific measurement requirements.

Fig. 14 is a top view of another microstrip magnetic sensor provided by an embodiment of the present invention. Fig. 15 is a sectional view along the D-D' section in Fig. 14 . As shown in FIG. 14 and FIG. 15 , the microstrip magnetic sensor includes two half-wavelength resonators 401 and a magnetoresistive element 402 . The half-wavelength resonator includes a transition portion 408 located at one end of the half-wavelength resonator close to the magnetoresistive element 402 . Through the transition part 408, the width of the end of the half-wavelength resonator 401 close to the magnetoresistive element 402 can be consistent with the width of the magnetoresistive element 402. The present invention does not limit the specific structure of the transition portion 408 .

The microwave magnetic sensor provided by the present invention also includes a coupling unit for measuring the resonant frequency of the microwave magnetic sensor. Fig. 16 is a schematic structural diagram of another microwave magnetic sensor provided by an embodiment of the present invention. As shown in FIG. 16 , in one embodiment, the magnetic sensor includes two coupling units 509 for measuring the resonant frequency of the microwave magnetic sensor. The coupling unit 509 is made of a section of transmission line whose characteristic impedance is consistent with that of the external measurement line, eg 50Ω. In one embodiment, as shown in FIG. 16 , the coupling between the coupling unit 509 and the half-wavelength resonator 101 is end-to-end coupling. In some other embodiments, the coupling between the coupling unit 509 and the half-wavelength resonator 101 may be other types of coupling, such as parallel coupling.

In some other embodiments, the microwave magnetic sensor may only include one coupling unit.

In one embodiment, the coupling unit 509 and the half-wavelength resonator 101 are made of the same type of transmission line. In some other embodiments, the coupling unit 509 and the half-wavelength resonator 101 may be made of different types of transmission lines.

In one embodiment, the coupling unit 509 and the half-wavelength resonator 101 are made of the same material. In some other embodiments, the coupling unit 509 and the half-wavelength resonator 101 may be made of different materials.

In one embodiment, the substrate, the half-wavelength resonator, the coupling unit and the ground are made of non-magnetic materials.

The invention also provides a measurement method of the microwave magnetic sensor. The method includes S1, obtaining a calibration curve between the first resonant frequency of the microwave magnetic sensor and the strength of the external magnetic field, the first resonant frequency being the lowest resonant frequency of the microwave magnetic sensor, and the calibration curve can be obtained by Obtained by measuring the first resonant frequency of the microwave magnetic sensor under external magnetic fields of different strengths within the range; S2, measuring the first resonant frequency of the microwave magnetic sensor under the magnetic field to be measured, and obtaining the magnetic field strength to be measured according to the calibration curve.

The above descriptions are only examples of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

A microwave magnetic sensor, comprising:

Two half-wavelength resonators, each of the half-wavelength resonators is a section of transmission line whose length is equal to half of the wavelength corresponding to its fundamental mode resonance frequency, and the two half-wavelength resonators have the same length and the same Fundamental mode resonant frequency;

A magneto-resistance element, the magneto-resistance element is located between the two half-wavelength resonators, and is equidistantly and symmetrically spaced from the two half-wavelength resonators, and the magneto-resistance element resonates with the two half-wavelength resonators The ends of the resonators constitute coupling capacitors through which the two half-wavelength resonators are coupled.
The microwave magnetic sensor according to claim 1, characterized in that:

The magneto-resistance element is a metal magneto-resistance element, including a giant magneto-resistance element, a tunnel magneto-resistance element or an anisotropic magneto-resistance element.
The microwave magnetic sensor according to claim 2, characterized in that:

The transmission line is a planar transmission line, including stripline, microstrip or coplanar line.
The microwave magnetic sensor according to claim 3, characterized in that,

The transmission line is a microstrip.
The microwave magnetic sensor according to claim 4, further comprising:

Substrates, made of low-loss dielectric materials including, but not limited to, silicon, gallium arsenide, FR-4, alumina, sapphire, quartz, or combinations thereof;

Ground wire, made of highly conductive metals, including but not limited to gold, silver, copper, or combinations thereof.
The microwave magnetic sensor according to claim 5, further comprising a protective layer, characterized in that:

The protective layer covers the magnetoresistive element;

The protective layer is made of low-k materials, including but not limited to fluorine-doped silica, silicone glass, porous silica or combinations thereof.
The microwave magnetic sensor according to claim 6, characterized in that:

The protective layer fills a gap between the resonator and the magnetoresistive element, and covers a part of the half-wavelength resonator.
The microwave magnetic sensor according to claim 5, characterized in that:

The magnetoresistive element has a stepped structure on each side;

The magnetoresistive element includes a top surface, a middle surface and a bottom surface, the bottom surface of the magnetoresistive element directly contacts the top surface of the substrate, and the middle surface and the top surface of the magnetoresistive element are located on the top surface of the half-wavelength resonator above, and cover part of the half-wavelength resonator on each side.
The microwave magnetic sensor according to claim 8, further comprising an isolation element, characterized in that:

the isolation element is disposed between the half-wavelength resonator and the magnetoresistive element;

The isolation element has a stepped structure;

The isolation element includes a top surface, a middle surface and a bottom surface, the top surface of the isolation element directly contacts the middle surface of the magnetoresistive element, and the middle surface of the isolation element directly contacts the top surface of the half-wavelength resonator, The bottom surface of the isolation element is directly on the top surface of the contact substrate.

The isolation elements are made of low-k materials including, but not limited to, fluorine-doped silica, silicone glass, porous silica, or combinations thereof.
The microwave magnetic sensor according to claim 9, further comprising a protective layer, characterized in that:

The protective layer covers the magnetoresistive element;

The protective layer is made of low-k materials, including but not limited to fluorine-doped silica, silicone glass, porous silica, or combinations thereof.
The microwave magnetic sensor according to claim 5, further comprising an isolation element, characterized in that:

said spacer element has a stepped structure on each side;

The isolation element includes a top surface, a middle surface and a bottom surface, the bottom surface of the isolation element directly contacts the top surface of the substrate, the middle surface of the isolation element directly contacts the top surface of the half-wavelength resonator, and at each The side covers a part of the half-wavelength resonator, and the magnetoresistive element is arranged on the top surface of the isolation element;

The material of the isolation element is a low-k material, including but not limited to fluorine-doped silicon dioxide, organic silicon glass, porous silicon dioxide or a combination thereof.
The microwave magnetic sensor according to claim 11, further comprising a protective layer, characterized in that:

The protective layer covers the magnetoresistive element;

The protective layer is made of low-k materials, including but not limited to fluorine-doped silica, silicone glass, porous silica, or combinations thereof.
The microwave magnetic sensor according to claim 5, characterized in that:

The half-wavelength resonator includes a transition portion, and the transition portion is located on a side of the half-wavelength resonator close to the magnetoresistive element;

The width of an end of the transition portion close to the magnetoresistive element is consistent with the width of the magnetoresistive element.
The microwave magnetic sensor according to claim 1, further comprising a coupling unit, characterized in that:

The coupling unit is used to measure the resonant frequency of the microwave magnetic sensor;

The coupling unit is made of a length of transmission line whose characteristic impedance is identical to that of the external measurement line.
The microwave magnetic sensor according to claim 14, characterized in that:

The coupling between the coupling unit and the half-wavelength resonator is end-to-end coupling.
The microwave magnetic sensor according to claim 14, characterized in that:

The coupling between the coupling unit and the half-wavelength resonator is parallel coupling.
The microwave magnetic sensor according to claim 14, characterized in that:

The substrate, the half-wavelength resonator, the coupling unit and the ground are made of non-magnetic material.
The measuring method of a kind of microwave magnetic sensor according to claim 1, comprising:

S1, obtaining the calibration curve between the first resonant frequency of the microwave magnetic sensor and the external magnetic field strength, the first resonant frequency is the lowest resonant frequency of the microwave magnetic sensor, and the calibration curve is passed in the range of interest obtained by measuring the first resonant frequency of the microwave magnetic sensor under external magnetic fields of different strengths;

S2. Measure the first resonant frequency of the microwave magnetic sensor under the magnetic field to be measured, and obtain the strength of the magnetic field to be measured according to the calibration curve.