Magneto-dependent sensor based on acoustic surface wave modal localization

Abstract

The invention provides a magneto-dependent sensor based on acoustic surface wave modal localization, and belongs to the technical field of magneto-dependent sensors. The interdigital transduction units are arranged on the end surface of the piezoelectric substrate at intervals along a first preset direction; the first preset direction is the length direction of the piezoelectric substrate; the coupling grid is arranged on the end surface of the piezoelectric substrate and is positioned on one side adjacent to the interdigital transduction unit; the two reflecting gratings are arranged on the end face of the piezoelectric substrate and located on the non-adjacent sides of the interdigital transduction units respectively. Wherein the mass of the interdigital transduction units distributed on the two sides of the central surface of the piezoelectric substrate is not equal. According to the invention, through reasonable arrangement of the interdigital electrodes, the coupling gates and the reflecting gates, when the magnetically sensitive interdigital transduction unit senses the change of an external magnetic field, the original symmetry of the device can be changed, so that the resonance state is interfered, and then the change condition of the external magnetic field is sensitively identified through the output of the interdigital electrodes according to the modal localization principle.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic sensors, and in particular to a magnetic sensor based on surface acoustic wave mode localization. Background Art

[0002] With the continuous advancement of technology, especially in materials science and micro-processing technology, new materials have significantly improved the sensitivity and stability of sensors. The advancement of micro-electromechanical system technology has also promoted the miniaturization and integration of magnetic sensors, but there are still some challenges, such as the impact of the external environment on sensor performance, and the stability and reliability of sensors in long-term use.

[0003] Modal localization refers to a phenomenon in which energy is spatially trapped after disorder is introduced into a coupled oscillating system, which means that the vibration amplitude in some areas increases significantly, while the vibration amplitude in other areas decreases or almost disappears. This is the phenomenon of modal energy being localized in space.

[0004] Therefore, it is necessary to provide a magnetic sensor based on surface acoustic wave modal localization, introduce modal localization on the basis of traditional magnetic sensors, so as to detect tiny changes in magnetic field intensity and achieve high-sensitivity sensing detection. Summary of the invention

[0005] In view of this, the present invention proposes a magnetic sensor based on surface acoustic wave modal localization, which introduces modal localization to detect tiny changes in magnetic field intensity and achieve high-sensitivity sensing detection.

[0006] The technical solution of the present invention is implemented as follows: The present invention provides a magnetic sensitive sensor based on surface acoustic wave mode localization, comprising:

[0007] Piezoelectric substrate;

[0008] The interdigital transducer units are arranged at different positions on the end surface of the piezoelectric substrate at intervals along a first preset direction; the first preset direction is the length direction of the piezoelectric substrate;

[0009] A coupling gate, arranged on the end surface of the piezoelectric substrate and located on a side adjacent to the interdigital transducer unit;

[0010] Two reflection gratings are arranged on the end surface of the piezoelectric substrate and are respectively located on the non-adjacent sides of the interdigital transducer unit;

[0011] The masses of the interdigital transducer units distributed on both sides of the central plane of the piezoelectric substrate are unequal.

[0012] Based on the above technical solutions, preferably, the interdigital transducer unit includes a first interdigital transducer, a second interdigital transducer, a third interdigital transducer, and a fourth interdigital transducer. The first interdigital transducer and the second interdigital transducer are adjacent and located on one side of the end face of the piezoelectric substrate, and the third interdigital transducer and the fourth interdigital transducer are adjacent and located on the other side of the end face of the piezoelectric substrate; the resistances of the first interdigital transducer, the second interdigital transducer, the third interdigital transducer, and the fourth interdigital transducer are the same, and the material of the fourth interdigital transducer is different from that of the first interdigital transducer, the second interdigital transducer, and the third interdigital transducer.

[0013] Preferably, the distances from the second interdigital transducer and the third interdigital transducer to the central plane of the piezoelectric substrate are equal; the distances from the first interdigital transducer and the fourth interdigital transducer to the central plane of the piezoelectric substrate are equal.

[0014] Further preferably, the first interdigital transducer, the second interdigital transducer, the third interdigital transducer, the coupling grating, and the two reflection gratings are all made of non-magnetic sensitive metal materials; the material of the fourth interdigital transducer is a magnetic sensitive metal material.

[0015] Even more preferably, the non-magnetic sensitive metal material is aluminum, copper, silver, or gold, and the magnetic sensitive metal material is nickel, iron, or cobalt.

[0016] Preferably, the interdigital transducer unit and the coupling grating are both configured with a plurality of metal electrode pairs, and each of the plurality of metal electrode pairs includes a first electrode and a second electrode arranged in an interleaved manner, and the lengths, widths, and spacings of adjacent first electrodes and second electrodes are equal.

[0017] Further preferably, the two reflection gratings each include a plurality of third electrodes, and the plurality of third electrodes are arranged at intervals along a first preset direction; the length and width of the third electrode are equal to the length and width of the second electrode, and the spacing between adjacent third electrodes is also equal to the spacing between adjacent first electrodes and second electrodes.

[0018] Even more preferably, the widths of the first interdigital transducer, the second interdigital transducer, the third interdigital transducer, and the fourth interdigital transducer along the first preset direction are equal, and the width of each interdigital transducer along the first preset direction is less than the width of the coupling grating along the first preset direction.

[0019] Even more preferably, the ratio of the width of a single reflection grating along the first preset direction to the width of the coupling grating along the first preset direction is 1:2.

[0020] Further preferably, the number of metal electrode pairs of the first interdigital transducer, the second interdigital transducer, the third interdigital transducer, and the fourth interdigital transducer is 10 pairs.

[0021] A magnetosensitive sensor based on surface acoustic wave mode localization provided by the present invention has the following beneficial effects compared with the prior art:

[0022] (1) Based on the mode localization principle on the basis of a traditional surface acoustic wave magnetosensitive sensor, by using the sensitive characteristics of this principle to symmetry, when the magnetic sensitive metal material of the interdigital transducer unit on one side of the piezoelectric substrate senses a magnetic field change, it will break the original resistance symmetry and thus change the output characteristics, which can be recognized, and high sensitivity to the magnetic field can be reflected;

[0023] (2) Specifically set the relationship between the width of the unilateral reflection grating and the width of the coupling grating to be 1:2, so that the overall sensor has good magnetic sensitivity characteristics, especially better sensitivity to magnetic fields in the range of 0-50 nT. Changing the width ratio constraint relationship will affect the magnetic sensitivity characteristics of the sensor. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for description in the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 Spring model diagram of mode localization related to a magnetosensitive sensor based on surface acoustic wave mode localization of the present invention;

[0026] Figure 2 Variation diagram of vector X1 with parameter δ under different coupling amounts of a magnetosensitive sensor based on surface acoustic wave mode localization of the present invention;

[0027] Figure 3 Structural schematic diagram of a magnetosensitive sensor based on surface acoustic wave mode localization of the present invention;

[0028] Figure 4 Structural diagram corresponding to Embodiment 1 of a magnetosensitive sensor based on surface acoustic wave mode localization of the present invention;

[0029] Figure 5 Test result diagram corresponding to Embodiment 1 of a magnetosensitive sensor based on surface acoustic wave mode localization of the present invention;

[0030] Figure 6 Relationship diagram between the applied magnetic field and the peak voltage of Embodiment 1 of a magnetosensitive sensor based on surface acoustic wave mode localization of the present invention;

[0031] Figure 7Schematic diagram of a comparative example of a magnetic sensor based on surface acoustic wave mode localization according to the present invention;

[0032] Figure 8 Test result diagram of a comparative example of a magnetic sensor based on surface acoustic wave mode localization according to the present invention.

[0033] Reference numerals: 01, piezoelectric substrate; 100, interdigital transducer unit; 03, first interdigital transducer; 04, second interdigital transducer; 06, third interdigital transducer; 07, fourth interdigital transducer; 05, coupling grating; 02, first reflection grating; 08, second reflection grating; 09, ground terminal; 200, first electrode; 300, second electrode; 400, third electrode. Detailed implementation manners

[0034] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] As Figure 1 、 Figure 2 and Figure 3 shown, the present invention provides a magnetic sensor based on surface acoustic wave mode localization, including:

[0036] Piezoelectric substrate 01;

[0037] Interdigital transducer unit 100, which is arranged at different positions on the end face of the piezoelectric substrate 01 at intervals along a first preset direction; the first preset direction is the length direction of the piezoelectric substrate 01, that is, Figure 3 the corresponding screen width direction in

[0038] Coupling grating 05 is arranged on the end face of the piezoelectric substrate 01 and is located on one side adjacent to the interdigital transducer unit 100;

[0039] Two reflection gratings are arranged on the end face of the piezoelectric substrate 01 and are respectively located on one side not adjacent to the interdigital transducer unit 100;

[0040] Among them, the masses of the interdigital transducer unit 100 distributed on both sides of the central plane in the horizontal direction of the piezoelectric substrate 01 are not equal.

[0041] Now in combination with the attached Figure 1 for illustration, Figure 1Starting from the simplest modal localization spring model, only considering the basic force conditions, analyze the forces on each part of the basic spring model and list the equations.

[0042] Taking the right as the positive direction and only considering one-dimensional motion, with k1, k2, and k C The coupling amounts of the three springs, and the mass blocks M1 and M2; for the left mass block, the force acting on it is: F1 = k C (x2 - x1) - k1x1;

[0043] For the right mass block, the force acting on it is: F2 = -k C (x2 - x1) - k2x2; x1 and x2 are the displacements of the mass blocks M1 and M2;

[0044] According to Newton's second law, it satisfies: k C (x2 - x1) - k1x1 = M1x″3(t); -k C (x2 - x1) - k2x2 = M2x″2(t); x″1(t) and x″2(t) are the second derivatives of the displacements respectively; the form directly solved from this equation is too complex, and in the stable mode, the solutions of x1 and x2 are in the form of wave functions, so let them be: After taking the second derivative, we get: Among them, when the two blocks are in the stable mode, their angular frequencies of motion must be equal, so let ω1 = ω2 = ω. The characteristic equation can be obtained:

[0045]

[0046] To further simplify, normalize each parameter, and at this time the masses of the two mass blocks are exactly the same, let k1 = k2 = k, k C / k = κ, M1 = M2 = M; the characteristic equation is rewritten as:

[0047] We can solve for λ and X: λ1 = 1, λ2 = 1 + 2κ, It can be seen that when the masses of the mass blocks are exactly equal, the system has two modes: in-phase and out-of-phase. In the in-phase state, their amplitudes and directions are the same, and in the out-of-phase state, their amplitudes are the same but the directions are opposite.

[0048] When the two mass blocks are not equal, assuming that the mass deviation ΔM of the two mass blocks is small, ΔM / M = δ << 1; then the characteristic equation becomes:

[0049] At this time, the solved λ and X eigenvalues are relatively complex, and the calculation is as follows:

[0050] To more clearly see the influence of the changes in parameters κ and δ on the formula, Figure 2 describes the first value in vector X1 of the curve. It can be seen that when the parameter δ = 0, regardless of the value of the parameter κ, the value of vector X1 is 1, that is, when the two mass blocks are exactly equal, their motion amplitudes are also exactly equal, regardless of the coupling amount k C is how much.

[0051] When the parameter δ takes a very small value, the value of the formula will change in the direction less than 1, and the smaller the parameter κ, the more obvious this change is, that is, as long as there is a slight difference between the two mass blocks, the kinetic energy of the system will be concentrated on the mass block with the larger mass.

[0052] As Figure 3 shown, the interdigital transducer unit 100 includes a first interdigital transducer 03, a second interdigital transducer 04, a third interdigital transducer 06, and a fourth interdigital transducer 07. The first interdigital transducer 03 and the second interdigital transducer 04 are adjacent and located on one side of the end face of the piezoelectric substrate 01. The third interdigital transducer 06 and the fourth interdigital transducer 07 are adjacent and located on the other side of the end face of the piezoelectric substrate 01; the resistances of the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, and the fourth interdigital transducer 07 are the same, and the material of the fourth interdigital transducer 07 is different from that of the first interdigital transducer 03, the second interdigital transducer 04, and the third interdigital transducer 06. It should be noted that the position of the fourth interdigital transducer 07 and the other three interdigital transducers can be interchanged, which does not affect the effect of this solution. For example, the fourth interdigital transducer 07 can be exchanged with any one of the first interdigital transducer, the second interdigital transducer, and the third interdigital transducer. The described position of the fourth interdigital transducer 07 is only used to illustrate the structure of the interdigital transducer unit 100 and is not regarded as a limitation of the solution.

[0053] Furthermore, in the present invention, the distances from the second interdigital transducer 04 and the third interdigital transducer 06 to the central plane in the horizontal direction of the piezoelectric substrate 01 are equal; the distances from the first interdigital transducer 03 and the fourth interdigital transducer 07 to the central plane in the horizontal direction of the piezoelectric substrate 01 are equal. Such a structure is to define the relative symmetry relationship of the positions of the four interdigital transducers.

[0054] The first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, the coupling grating 05, and the two reflection gratings, namely the first reflection grating 02 and the second reflection grating 08, are all made of non-magnetic sensitive metal materials; the fourth interdigital transducer 07 is made of magnetic sensitive metal materials. Specifically, the non-magnetic sensitive metal materials are aluminum, copper, silver or gold, and aluminum is selected as an example in this embodiment; the magnetic sensitive metal materials are nickel, iron or cobalt, and nickel is selected as an example in this embodiment. In this way, when the external magnetic field changes, only the fourth interdigital transducer 07 made of magnetic sensitive metal materials is affected, while other parts are not directly affected by the magnetic field.

[0055] The interdigital transducer unit 100 and the coupling grating 05 are both configured with a plurality of metal electrode pairs. The plurality of metal electrode pairs all include a first electrode 200 and a second electrode 300 arranged in an interleaved manner. The lengths, widths and spacings of adjacent first electrodes 200 and second electrodes 300 are equal. Each of the two reflection gratings includes a plurality of third electrodes 400, and the plurality of third electrodes 400 are all arranged at intervals along a first preset direction; the length and width of the third electrode 400 are equal to the length and width of the second electrode 300, and the spacing between adjacent third electrodes 400 is also equal to the spacing between adjacent first electrodes 200 and second electrodes 300. The first electrode 200 and the second electrode 300 of the metal electrode pair extend relatively and do not contact each other, and there is a gap therebetween. Here, it is stipulated that the gap is equivalent to the width of the first electrode or the second electrode.

[0056] The widths of the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06 and the fourth interdigital transducer 07 along the first preset direction are all equal, and the width of each interdigital transducer along the first preset direction is less than the width of the coupling grating 05 along the first preset direction.

[0057] In order to ensure the magnetic sensitivity of the sensor, the present invention further defines that the ratio of the width of a single reflection grating along the first preset direction to the width of the coupling grating 05 along the first preset direction is 1:2.

[0058] The number of metal electrode pairs of the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06 and the fourth interdigital transducer 07 is 10 pairs. It can be increased or decreased according to actual needs.

[0059] The technical effects of the present invention will be described below through Example 1 and Comparative Example.

[0060] Embodiment 1: A grounding end 09 is prepared on the surface of a piezoelectric substrate 01 made of 128° YX-LiNbO₃ along the crystal orientation; then a first interdigital transducer 03, a second interdigital transducer 04, a third interdigital transducer 06, and a fourth interdigital transducer 07 are prepared along the first preset direction of the piezoelectric substrate 01 and the extension direction of the grounding end 09; a coupling grating 05 is prepared on the surface of the piezoelectric substrate 01 between the second interdigital transducer 04 and the third interdigital transducer 06, and a first reflection grating 02 and a second reflection grating 08 are respectively prepared outside the first interdigital transducer 03 and the fourth interdigital transducer 07. As Figure 4 shown, the widths of the first electrode, the second electrode, and the third electrode and the pitch p between adjacent electrodes are all 5 μm; the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, the coupling grating 05, the first reflection grating 02, and the second reflection grating 08 are all made of metallic aluminum and have a thickness of 100 nm; the fourth interdigital transducer 07 is made of metallic nickel with a metallization rate of 50% and a thickness of 250 nm. The widths of the first reflection grating 02 and the second reflection grating 08 along the first preset direction are d1 = d7 = 400p = 2 mm. The widths of the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, and the fourth interdigital transducer 07 along the first preset direction are all d2 = d3 = d5 = d6 = 40p = 200 μm; the width of the middle coupling grating 05 along the first preset direction is d4 = 800p = 4 mm. Ensure that the width of a single reflection grating: the width of the coupling grating = 1:2.

[0061] According to the above parameters, radio frequency voltages are applied to the first interdigital transducer 03 and the fourth interdigital transducer 07 on both sides, and Rayleigh waves of about 196 MHz can be excited in the piezoelectric substrate 01, and the direction of sound wave propagation is perpendicular to the length extension direction of each electrode. When the fourth interdigital transducer 07 senses a change in the external magnetic field, its resistance will change, which will change the originally symmetric pattern of the device, and thus can be very sensitively identified by the electrical signal output by the third interdigital transducer 06 according to the principle of mode localization.

[0062] When there is no external magnetic field, a spike appears in the test voltage near the resonant frequency. As the external magnetic field continues to increase, the original symmetry of the device is destroyed, resulting in the interference of the resonant state, and the originally sharp spike shows a decrease in the peak frequency, and its induced sensitivity can reach the order of nT. The test results are as Figure 5 shown.

[0063] After multiple groups of measurements, the relationship between the externally applied magnetic field and the induced voltage is finally obtained, as Figure 6 . It can be seen that this mode localization sensor is more sensitive to magnetic field changes within 50 nT, especially in the range of 0 to 20 nT.

[0064] Comparative Example: The first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, and the fourth interdigital transducer 07 are fabricated on the surface of a piezoelectric substrate 01 made of 128° YX-LiNbO3; a coupling grating 05 is fabricated on the surface of the piezoelectric substrate 01 between the second interdigital transducer 04 and the third interdigital transducer 06, and a first reflection grating 02 and a second reflection grating 08 are respectively fabricated outside the first interdigital transducer 03 and the fourth interdigital transducer 07. The content is exactly the same as that of Example 1. As Figure 7 shown, the widths of the first electrode, the second electrode, and the third electrode and the pitch p between adjacent electrodes are all 5 μm; the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, the coupling grating 05, the first reflection grating 02, and the second reflection grating 08 are all made of metallic aluminum and have a thickness of 100 nm; the fourth interdigital transducer 07 is made of metallic nickel with a metallization rate of 50% and a thickness of 250 nm.

[0065] The difference is that the widths of the first reflection grating 02 and the second reflection grating 08 along the first preset direction are d1 = d7 = 400p = 2 mm. The widths of the first interdigital transducer 03, the second interdigital transducer 04, the third interdigital transducer 06, and the fourth interdigital transducer 07 along the first preset direction are all d2 = d3 = d5 = d6 = 40p = 200 μm; the width of the middle coupling grating 05 along the first preset direction is d4 = 400p = 2 mm. Ensure that the width of a single reflection grating: the width of the coupling grating = 1:1.

[0066] According to the above parameters, radio frequency voltages are applied to the first interdigital transducer 03 and the fourth interdigital transducer 07 on both sides, and Rayleigh waves of about 196 MHz can be excited in the piezoelectric substrate 01. The propagation direction of the acoustic waves is perpendicular to the length extension direction of each electrode. At this time, the ability of the device to sense the magnetic field intensity decreases significantly, as Figure 8 shown. It can be seen that only when the width of a single reflection grating: the width of the coupling grating = 1:2, the magnetosensitive sensor based on surface acoustic wave mode localization of this embodiment has better sensitivity.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A magnetosensitive sensor based on surface acoustic wave mode localization, characterized in that, Comprising: A piezoelectric substrate (01); Interdigital transducer units (100) are arranged at different positions on the end face of the piezoelectric substrate (01) at intervals along a first preset direction; the first preset direction is the length direction of the piezoelectric substrate (01); A coupling grating (05) is arranged on the end face of the piezoelectric substrate (01) and is located on one side adjacent to the interdigital transducer units (100); Two reflection gratings are arranged on the end face of the piezoelectric substrate (01) and are respectively located on the non-adjacent sides of the interdigital transducer units (100); Wherein, the masses of the interdigital transducer units (100) distributed on both sides of the central plane of the piezoelectric substrate (01) are not equal.

2. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 1, characterized in that, The interdigital transducer unit (100) includes a first interdigital transducer (03), a second interdigital transducer (04), a third interdigital transducer (06) and a fourth interdigital transducer (07). The first interdigital transducer (03) and the second interdigital transducer (04) are adjacent and located on one side of the end face of the piezoelectric substrate (01). The third interdigital transducer (06) and the fourth interdigital transducer (07) are adjacent and located on the other side of the end face of the piezoelectric substrate (01). The resistances of the first interdigital transducer (03), the second interdigital transducer (04), the third interdigital transducer (06) and the fourth interdigital transducer (07) are the same, and the material of the fourth interdigital transducer (07) is different from that of the first interdigital transducer (03), the second interdigital transducer (04) and the third interdigital transducer (06).

3. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 2, characterized in that, The distances from the second interdigital transducer (04) and the third interdigital transducer (06) to the central plane of the piezoelectric substrate (01) are equal; the distances from the first interdigital transducer (03) and the fourth interdigital transducer (07) to the central plane of the piezoelectric substrate (01) are equal.

4. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 3, characterized in that, The first interdigital transducer (03), the second interdigital transducer (04), the third interdigital transducer (06), the coupling grating (05) and the two reflection gratings are all made of non-magnetic sensitive metal materials; the material of the fourth interdigital transducer (07) is a magnetic sensitive metal material.

5. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 4, characterized in that, The non-magnetic sensitive metal material is aluminum, copper, silver or gold, and the magnetic sensitive metal material is nickel, iron or cobalt.

6. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 2, wherein Both the interdigital transducer unit (100) and the coupling grating (05) are configured with a plurality of metal electrode pairs, and the plurality of metal electrode pairs all include a first electrode (200) and a second electrode (300) arranged alternately. The lengths, widths and spacings of adjacent first electrodes (200) and second electrodes (300) are equal.

7. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 6, characterized in that, Both of the two reflection gratings include a plurality of third electrodes (400), and the plurality of third electrodes (400) are all arranged at intervals along the first preset direction; the length and width of the third electrode (400) are equal to the length and width of the second electrode (300), and the spacing between adjacent third electrodes (400) is also equal to the spacing between adjacent first electrodes (200) and second electrodes (300).

8. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 7, characterized in that, The widths of the first interdigital transducer (03), the second interdigital transducer (04), the third interdigital transducer (06), and the fourth interdigital transducer (07) along the first preset direction are all equal, and the width of each interdigital transducer along the first preset direction is less than the width of the coupling grating (05) along the first preset direction.

9. The magnetosensitive sensor based on surface acoustic wave mode localization according to claim 7, wherein The ratio of the width of a single reflection grating along the first preset direction to the width of the coupling grating (05) along the first preset direction is 1:

2.

10. A magnetosensitive sensor based on surface acoustic wave mode localization according to claim 6, characterized in that, The number of metal electrode pairs of the first interdigital transducer (03), the second interdigital transducer (04), the third interdigital transducer (06), and the fourth interdigital transducer (07) is 10 pairs.

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