A vortex suppression structure and a method of making the same

Abstract

This invention relates to an eddy current suppression structure, comprising a magnetostrictive layer and an insulating dielectric layer disposed within the magnetostrictive layer to interrupt eddy currents and thus suppress eddy current losses in a bulk acoustic wave magnetoelectric antenna. This invention reduces eddy current losses by inserting an insulating dielectric layer into the magnetostrictive layer, thereby improving the radiation efficiency of the bulk acoustic wave magnetoelectric antenna. It solves the problem of stress discontinuity and low radiation efficiency of the magnetoelectric antenna caused by air gaps between the magnetostrictive layer and existing technologies. Using an insulating dielectric layer as a spacer improves the soft magnetic properties of the magnetostrictive layer, effectively reduces its coercivity, and increases the sensitivity of the radiation region. Simulation analysis shows that this solution can effectively reduce eddy current losses by more than 65%, significantly improving the radiation efficiency of the magnetoelectric antenna.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microelectromechanical systems, specifically to an eddy current suppression structure and its fabrication method. Background Technology

[0002] Currently, antennas commonly used in devices such as smartphones, tablets, radio frequency devices, and radar are electrically small antennas based on the principle of current conduction. These antennas are typically large in size, making miniaturization difficult, and also suffer from drawbacks such as impedance matching difficulties and low radiation efficiency. Bulk acoustic wave magnetoelectric antennas utilize the principle of bulk acoustic wave resonance and the magnetoelectric effect to radiate electromagnetic signals, fundamentally solving the problems of impedance matching difficulties and low radiation efficiency of electrically small antennas. Furthermore, the use of acoustic wave resonance principles allows for device miniaturization. Bulk acoustic wave magnetoelectric antennas are composed of a cross-composite structure of a piezoelectric layer and a magnetostrictive layer.

[0003] In bulk acoustic wave (SAW) magnetoelectric antennas, the magnetostrictive layer serves as the radiating layer of the transmitting antenna. Within this layer, electromagnetic signals are generated through the mechatronic effect, radiating electromagnetic waves to the outside world. Its energy utilization directly determines the radiation efficiency of the transmitting antenna. The magnetostrictive layer is often made of FeGaB magnetic thin film with high conductivity. Under the excitation of the internal magnetic field, it generates significant eddy current losses, affecting the radiated power of the transmitting antenna. Reducing eddy current losses while ensuring the good soft magnetic properties of the magnetostrictive layer will greatly improve the radiation efficiency of the magnetoelectric antenna. When SAW magnetoelectric antennas are used in radio frequency systems, eddy current losses cause excessive energy loss, leading to reduced antenna radiation efficiency and limiting its application range.

[0004] In their paper titled "3D ADI-FDTD Modeling of Platform Reduction with Thin Film Ferromagnetic Material," Zhi Yao and Yuanxun Ethan Wang proposed an eddy current suppression method based on 3D ADI-FDTD. This method utilizes the segmentation of the magnetostrictive layer into long strips to break eddy current loops, thereby suppressing eddy current losses. The key technologies of this method are: (i) the width of the segmented strips should be comparable to the thickness, ensuring that the broken eddy current loops are sufficiently small; (ii) the longitudinal direction of the strips should be along the magnetic flux direction. An air gap exists between adjacent strips. Due to the high conductivity of the magnetostrictive layer, most of the electromagnetic field is concentrated in the air gap. The structure is shown in the attached figure. Figure 1 and 2 .

[0005] The proposed eddy current loss suppression method, while effectively suppressing eddy current loss, also significantly reduces the radiation efficiency of the magnetoelectric antenna. The main problems are: (i) Using air gaps as the left-right gaps (along the y-axis) and top-bottom gaps (along the z-axis) between the segmented strips results in stress not being continuously transmitted between the left-right and top-bottom layers during actual operation. Only the lower magnetostrictive film is active; there is no stress transmission in the upper magnetostrictive layer, preventing the generation of electromagnetic waves and thus greatly reducing the overall radiation efficiency of the magnetostrictive layer. (ii) In this scheme, each air gap along the y-axis is 0.2 μm wide, accounting for 1 / 5 of the width of a single magnetic strip, and each air gap along the z-axis is 0.3 μm thick, accounting for 1 / 2 of the width of a single magnetic strip. While larger air gaps can effectively suppress eddy current loss, they reduce the soft magnetic properties of the entire magnetostrictive layer, leading to excessively low radiation efficiency of the magnetoelectric antenna. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an eddy current suppression structure and its preparation method.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: an eddy current suppression structure, including a magnetostrictive layer and an insulating dielectric layer, wherein the insulating dielectric layer is disposed within the magnetostrictive layer for interrupting eddy currents.

[0008] The beneficial effects of this invention are as follows: By inserting an insulating dielectric layer into the magnetostrictive layer, this invention reduces eddy current losses, thereby improving the radiation efficiency of the bulk acoustic wave magnetoelectric antenna. This solves the problem of stress discontinuity and low radiation efficiency of the magnetoelectric antenna caused by air gaps separating the magnetostrictive layer in existing technologies. Using an insulating dielectric layer as a spacer improves the soft magnetic properties of the magnetostrictive layer, effectively reduces its coercivity, and increases the sensitivity of the radiation region. Simulation analysis shows that this solution can effectively reduce eddy current losses by more than 65%, significantly improving the radiation efficiency of the magnetoelectric antenna.

[0009] Based on the above technical solution, the present invention can be further improved as follows:

[0010] Furthermore, a first insulating dielectric layer is disposed within the magnetostrictive layer along its thickness direction and / or a second insulating dielectric layer is disposed within the magnetostrictive layer along its width direction.

[0011] The beneficial effect of adopting the above-mentioned further solution is that the present invention divides eddy currents into volume eddy currents and surface eddy currents based on the skin effect of the induced current in the magnetostrictive layer. The first insulating dielectric layer can effectively suppress volume eddy currents, thereby reducing eddy current losses; the second insulating dielectric layer can effectively suppress surface eddy currents, thereby reducing eddy current losses.

[0012] Furthermore, at least one layer of the first insulating dielectric layer is disposed within the magnetostrictive layer along its thickness direction.

[0013] The beneficial effect of adopting the above-mentioned further solution is that the first insulating dielectric layer can effectively suppress bulk eddy currents, thereby reducing eddy current losses.

[0014] Furthermore, the first insulating dielectric layer consists of three parallel layers, each with a thickness of 5-100 nm. The magnetostrictive layer is made of FeGaB thin film with a total thickness of 1 μm. The conductivity of the first insulating dielectric layer ranges from 0-100 S / m. The first insulating dielectric layer is made of one or more of Al2O3, Si3N4, and AlN.

[0015] The beneficial effects of adopting the above-mentioned further scheme are that, as shown by simulation results, three layers are sufficient to solve the problem of volume eddy current suppression; the first insulating dielectric layer is 5-100nm, and the volume eddy current can be well suppressed; FeGaB thin film is a high-quality magnetostrictive layer material; when the insulating dielectric layer is the above-mentioned material, it has a very good eddy current suppression effect.

[0016] Furthermore, at least one second insulating dielectric layer is disposed within the magnetostrictive layer along its width direction.

[0017] The beneficial effect of adopting the above-mentioned further solution is that the second insulating dielectric layer can effectively suppress surface eddy currents, thereby reducing eddy current losses.

[0018] Furthermore, the second insulating dielectric layer consists of three parallel layers, each with a thickness of 5-30 nm. The magnetostrictive layer is made of FeGaB thin film with a total thickness of 1 μm. The conductivity of the second insulating dielectric layer ranges from 0-100 S / m. The second insulating dielectric layer is made of one or more of Al2O3, Si3N4, and AlN.

[0019] The beneficial effects of adopting the above-mentioned further scheme are that, as shown by simulation results, three layers are sufficient to solve the surface eddy current suppression problem; the second insulating dielectric layer is 5-30nm, and surface eddy currents can be well suppressed; FeGaB thin film is a high-quality magnetostrictive layer material; when the insulating dielectric layer is the above-mentioned material, it has a very good eddy current suppression effect.

[0020] Furthermore, at least one first insulating dielectric layer is disposed within the magnetostrictive layer along its thickness direction, and at least one second insulating dielectric layer is disposed within the magnetostrictive layer along its width direction, with the first insulating dielectric layer and the second insulating dielectric layer being disposed alternately.

[0021] The beneficial effect of the above-mentioned further solution is that by inserting insulating dielectric layers that are alternately spaced along the thickness and width directions into the magnetostrictive layer, the bulk eddy current and surface eddy current losses are reduced. A comprehensive insulating dielectric layer isolation structure considering both bulk and surface eddy currents is proposed, minimizing the eddy current loss of the magnetostrictive layer. This solves the problem of stress discontinuity and low radiation efficiency of the magnetoelectric antenna caused by air gaps in existing solutions. Using insulating dielectric layers as spacers improves the soft magnetic properties of the magnetostrictive layer, effectively reduces its coercivity, and increases the sensitivity of the radiation region. Simulation analysis shows that this solution can effectively reduce eddy current losses by more than 65%, significantly improving the radiation efficiency of the magnetoelectric antenna.

[0022] Furthermore, the first insulating dielectric layer consists of three parallel layers, and the second insulating dielectric layer consists of three parallel layers. The thickness of each first insulating dielectric layer is 5-100 nm, and the thickness of each second insulating dielectric layer is 5-30 nm. The magnetostrictive layer is made of FeGaB thin film with a total thickness of 1 μm. The conductivity range of the first and second insulating dielectric layers is 0-100 S / m. Both the first and second insulating dielectric layers are made of one or more of Al2O3, Si3N4, and AlN.

[0023] The beneficial effect of adopting the above-mentioned further scheme is that, as shown by simulation results, three layers are sufficient to solve the surface eddy current suppression problem. The thickness of the first insulating dielectric layer is 5-100 nm, and the thickness of the second insulating dielectric layer is 5-30 nm. Surface eddy currents can be well suppressed. The above limits the suppression of eddy current losses in the magnetic film while ensuring that the size of the insulating dielectric layer is as small as possible. A magnetic film structure with a minimum-sized insulating dielectric inserted to suppress eddy currents is proposed. This structure can effectively suppress eddy current losses in the magnetostrictive layer while effectively ensuring the good soft magnetic properties of the magnetostrictive layer, improving the radiation efficiency of the magnetoelectric antenna, and making the bulk acoustic wave magnetoelectric antenna more suitable for wireless communication applications. FeGaB thin film is a high-quality magnetostrictive layer material; when the insulating dielectric layer is made of the above material, it has a good eddy current suppression effect.

[0024] The present invention also relates to a magnetoelectric antenna, including an upper electrode and the eddy current suppression structure, wherein the eddy current suppression structure is disposed on the upper electrode.

[0025] This invention also relates to a method for preparing the eddy current suppression structure, comprising: Step 1: depositing a magnetostrictive layer on a body (upper electrode of a bulk acoustic resonator) using magnetron sputtering; Step 2: depositing a first insulating dielectric layer along its thickness direction on the magnetostrictive layer formed in Step 1 using magnetron sputtering; Step 3: depositing another magnetostrictive layer on the first insulating dielectric layer formed in Step 2; Step 4: directly obtaining the eddy current suppression structure, or repeating Steps 2-3 at least once to obtain the eddy current suppression structure; or, Step a: depositing a magnetostrictive layer on a body (upper electrode of a bulk acoustic resonator) using magnetron sputtering. Step b: Deposit a magnetostrictive layer using magnetron sputtering; Step c: Uniformly coat the magnetostrictive layer with a layer of photoresist using a spin coater, then sequentially perform pre-baking, exposure, and development; Step d: Etch at least one groove in the thickness direction of the magnetostrictive layer on the structure formed in step b using dry etching; Step e: Sputter at least one second insulating dielectric layer in the thickness direction of the magnetostrictive layer on the structure formed in step c using magnetron sputtering; Step f: Remove the photoresist from the surface of the magnetostrictive layer using a metal lift-off process; Step f: Remove the first insulating dielectric layer protruding above the surface of the magnetostrictive layer using chemical mechanical polishing. The insulating dielectric layer is ground smooth; or, step A: deposit a magnetostrictive layer on the body (upper electrode of the bulk acoustic resonator) using magnetron sputtering; step B: deposit a first insulating dielectric layer in the thickness direction of the magnetostrictive layer formed in step A on the magnetostrictive layer formed in step A using magnetron sputtering; step C: deposit a magnetostrictive layer on the first insulating dielectric layer formed in step B; step D: directly obtain the first insulating dielectric layer structure, or repeat steps B and C at least once to obtain the first insulating dielectric layer structure; step E: uniformly cover the first insulating dielectric layer structure with a spin coater. A layer of photoresist is applied, followed by pre-baking, exposure, and development. Step F: At least one groove in the width direction of the magnetostrictive layer is etched on the structure formed in step E using dry etching. Step G: At least one second insulating dielectric layer in the width direction of the magnetostrictive layer is formed by magnetron sputtering on the structure formed in step F. Step H: The photoresist on the surface of the first insulating dielectric layer structure formed in step D is removed using a metal lift-off process. Step I: The second insulating dielectric layer that protrudes above the surface of the first insulating dielectric layer structure formed in step D is smoothed using chemical mechanical polishing.

[0026] The advantage of adopting the above-mentioned further solution is that the above method can be used to produce eddy current suppression structures simply, quickly, and while ensuring the eddy current suppression function, thereby improving the radiation efficiency of the magnetoelectric antenna. Attached Figure Description

[0027] Figure 1For existing eddy current loss suppression structures Figure 1 ;

[0028] Figure 2 For existing eddy current loss suppression structures Figure 2 ;

[0029] Figure 3 This is a schematic diagram of the magnetostrictive layer eddy current suppression structure of the present invention;

[0030] Figure 4 This is a diagram of the magnetostrictive layer eddy current suppression structure of the present invention;

[0031] Figure 5 This invention relates to a 3×3 eddy current suppression structure for the magnetostrictive layer;

[0032] Figure 6 This is a process flow diagram of the eddy current suppression structure of the present invention;

[0033] Figure 7 This is a schematic diagram illustrating the effect of Al2O3 film thickness on surface loss according to the present invention;

[0034] Figure 8 This is a schematic diagram illustrating the effect of the number of Al2O3 film layers on surface loss in this invention;

[0035] Figure 9 This is a schematic diagram illustrating the effect of Al2O3 film thickness on bulk loss in this invention.

[0036] Figure 10 This is a schematic diagram illustrating the effect of the number of Al2O3 film layers on bulk loss in this invention;

[0037] Figure 11 This is a schematic diagram of the total loss density corresponding to different Al2O3 thicknesses in this invention.

[0038] The attached diagram lists the components represented by each number as follows:

[0039] 1. Magnetostrictive layer, 2. First insulating dielectric layer, 3. Second insulating dielectric layer, 4. Upper pole of bulk acoustic resonator, 5. Photoresist, 6. Mask, 7. Air gap. Detailed Implementation

[0040] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0041] The surface eddy currents and volume eddy currents of the magnetostrictive layer were simulated using Comsol simulation software, and the verification results are shown in the figures.

[0042] like Figure 7As shown, the surface loss density decreases significantly when the Al2O3 thickness (insulating dielectric layer) is within 5 nm. Although it gradually decreases thereafter, the rate of decrease remains within 5%, effectively suppressing surface eddy currents. Therefore, surface eddy current losses are well suppressed when the Al2O3 thickness is within 5 nm, and the Al2O3 thickness can be appropriately increased according to process conditions. While keeping the total thickness of the inserted Al2O3 insulating layer constant, it is divided into 2, 3, 4, and 5 layers, uniformly spaced within the FeGaB metal layer. Figure 8 When the total thickness is 100 nm (which can be appropriately increased according to process conditions), the surface eddy current density variation trend corresponding to different Al2O3 insulating layer numbers shows that as the number of layers increases, the surface loss density decreases significantly, but the reduction rate after 3 layers is less than 20%, and the reduction rate gradually flattens out. Therefore, 3 layers are sufficient to solve the problem of surface eddy current suppression.

[0043] Based on the simulation results, the variation trend of bulk loss density corresponding to different Al2O3 thicknesses is as follows: Figure 9 As shown, after adding 5 nm of Al2O3, the bulk loss density decreased by more than 60%. The eddy current loss density was lowest when the Al2O3 thickness was around 30 nm, followed by a slight increase at a rate of less than 1%. Therefore, bulk eddy currents can be well suppressed for Al2O3 insulating layer thicknesses between 5 and 30 nm. Setting the total Al2O3 layer thickness to 30 nm, where the bulk eddy current loss density is minimum, and dividing it into 2, 3, 4, and 5 layers, the results are as follows... Figure 10 As shown, the bulk eddy current loss density decreases significantly with the increase of the number of Al2O3 insulating layers. Similar to the surface loss density, the rate of decrease gradually slows down after three layers.

[0044] Taking into account the optimal isolation methods for both surface vortices and volume vortices, the following method was adopted: Figure 6 The 3×3 cross-interval method was used to calculate surface eddies and volume eddies, and the simulation results of the total loss density are as follows: Figure 11 As shown, it is clear that the total loss density is lowest when using a cross-spacer. With an Al₂O₃ thickness of 10 nm along both the thickness direction (z-axis) and width direction (y-axis), inserting three Al₂O₃ insulating layers along the thickness direction (z-axis) and three along the width direction (y-axis) reduces the total loss density by approximately 10% and 47%, respectively. The 3×3 cross-spacer method achieves a reduction of 65%, demonstrating the highest eddy current suppression efficiency. Therefore, the 3×3 cross-spacer method is the optimal method for eddy current suppression.

[0045] Example 1

[0046] like Figure 3-11As a basic solution of the present invention, an eddy current suppression structure includes a magnetostrictive layer 1 and an insulating dielectric layer. The insulating dielectric layer is disposed within the magnetostrictive layer 1 and is used to interrupt eddy currents, thereby suppressing eddy current loss of the bulk acoustic wave magnetoelectric antenna.

[0047] like Figure 3 As a further embodiment, at least one layer of the first insulating dielectric layer 2 is disposed within the magnetostrictive layer 1 along its thickness direction.

[0048] As a further embodiment, the first insulating dielectric layer 2 consists of three parallel layers, each with a thickness of 5-100 nm. The magnetostrictive layer 1 is made of FeGaB thin film with a total thickness of 1 μm. The conductivity of the first insulating dielectric layer 2 ranges from 0-100 S / m. The first insulating dielectric layer 2 is made of one or more of Al2O3, Si3N4, and AlN.

[0049] Specifically, such as Figure 3 The arrow indicates the direction of magnetic flux. The first insulating dielectric layer is set parallel to the XOY plane (thickness direction) to achieve its function of interrupting eddy currents.

[0050] like Figure 3 and 6 The method for preparing the eddy current suppression structure includes the following steps: Step 1: Depositing a magnetostrictive layer 1 on the upper electrode of the body acoustic resonator using magnetron sputtering; Step 2: Depositing a first insulating dielectric layer 2 along its thickness direction on the magnetostrictive layer 1 formed in Step 1 using magnetron sputtering; Step 3: Depositing a magnetostrictive layer 1 again on the first insulating dielectric layer 2 formed in Step 2; Step 4: Repeating Step 2 above to obtain the eddy current suppression structure.

[0051] Example 2

[0052] like Figure 3-11 As a basic solution of the present invention, an eddy current suppression structure includes a magnetostrictive layer 1 and an insulating dielectric layer. The insulating dielectric layer is disposed within the magnetostrictive layer 1 and is used to interrupt eddy currents, thereby suppressing eddy current loss of the bulk acoustic wave magnetoelectric antenna.

[0053] like Figure 4 As a further embodiment, at least one layer of the second insulating dielectric layer 3 is disposed within the magnetostrictive layer 1 along its width direction.

[0054] As a further embodiment, the second insulating dielectric layer 3 consists of three parallel layers, each with a thickness of 5-30 nm. The magnetostrictive layer 1 is made of FeGaB thin film with a total thickness of 1 μm. The conductivity of the second insulating dielectric layer 3 ranges from 0-100 S / m. The second insulating dielectric layer 3 is made of one or more of Al2O3, Si3N4, and AlN.

[0055] Specifically, such as Figure 4 As mentioned above, the arrow indicates the direction of magnetic flux, and the second insulating dielectric layer is set parallel to the XOZ plane (width direction) to achieve its function of interrupting eddy currents; while if the insulating layer is set parallel to the ZOY plane (length direction), it cannot interrupt eddy currents.

[0056] like Figure 4 and 6 The method for fabricating the eddy current suppression structure includes the following steps: Step a: Depositing a magnetostrictive layer 1 on the upper electrode of the bulk acoustic wave resonator using magnetron sputtering; Step b: Uniformly covering the magnetostrictive layer 1 with a photoresist 5 using a spin coater, followed by pre-baking, exposure, and development; Step c: Etching three grooves in the thickness direction of the magnetostrictive layer 1 onto the structure formed in step b using dry etching; Step d: Sputtering three second insulating dielectric layers 3 in the thickness direction of the magnetostrictive layer 1 onto the structure formed in step c using magnetron sputtering; Step e: Removing the photoresist 5 from the surface of the magnetostrictive layer 1 using a metal stripping process; Step f: Flattening the second insulating dielectric layers 3 that protrude above the surface of the magnetostrictive layer 1 using chemical mechanical polishing. In this method, a mask 6 is placed on the photoresist before etching to ensure that the non-grooved areas are not etched.

[0057] Example 3

[0058] like Figure 3-11 As a basic solution of the present invention, an eddy current suppression structure includes a magnetostrictive layer 1 and an insulating dielectric layer. The insulating dielectric layer is disposed within the magnetostrictive layer 1 and is used to interrupt eddy currents, thereby suppressing eddy current loss of the bulk acoustic wave magnetoelectric antenna.

[0059] like Figure 5 and 6 As a further embodiment, at least one first insulating dielectric layer 2 is disposed in the magnetostrictive layer 1 along its thickness direction, and at least one second insulating dielectric layer 3 is disposed in the magnetostrictive layer 1 along its width direction, with the first insulating dielectric layer 2 and the second insulating dielectric layer 3 being disposed alternately.

[0060] like Figure 5 and 6As a further embodiment, the first insulating dielectric layer 2 consists of three parallel layers, and the second insulating dielectric layer 3 consists of three parallel layers. The thickness of each first insulating dielectric layer 2 layer is 5-100 nm, and the thickness of each second insulating dielectric layer 3 layer is 5-30 nm. The magnetostrictive layer 1 is made of FeGaB thin film with a total thickness of 1 μm. The conductivity range of the first insulating dielectric layer 2 and the second insulating dielectric layer 3 is 0-100 S / m. Both the first insulating dielectric layer 2 and the second insulating dielectric layer 3 are made of one or more of Al2O3, Si3N4, and AlN.

[0061] Specifically, such as Figure 5 As mentioned above, the arrow indicates the direction of magnetic flux. The first insulating dielectric layer is set parallel to the XOY plane (thickness direction) to achieve its function of interrupting eddy currents. The second insulating layer is set parallel to the ZOX plane (width direction) to achieve its function of interrupting eddy currents. However, if the insulating layer is parallel to the ZOY plane (length direction), it cannot interrupt eddy currents.

[0062] like Figure 5 and 6 The method for fabricating the eddy current suppression structure includes step A: depositing a magnetostrictive layer 1 on the upper electrode of a bulk acoustic wave resonator using magnetron sputtering; step B: depositing a first insulating dielectric layer 2 in the thickness direction of the magnetostrictive layer 1 formed in step A on the magnetostrictive layer 1 formed in step A using magnetron sputtering; step C: depositing a magnetostrictive layer 1 on the first insulating dielectric layer 2 formed in step B; step D: repeating steps B and C twice to obtain the first insulating dielectric layer structure; step E: uniformly covering the first insulating dielectric layer structure with a photoresist 5 using a spin coater, and then... The process involves pre-baking, exposure, and development in sequence; Step F: At least one groove in the width direction of the magnetostrictive layer 1 is etched onto the structure formed in step E using dry etching; Step G: At least one second insulating dielectric layer 4 in the width direction of the magnetostrictive layer 1 is formed by magnetron sputtering onto the structure formed in step F; Step H: The photoresist 5 on the surface of the first insulating dielectric layer structure formed in step D is removed using a metal lift-off process; Step I: The second insulating dielectric layer 3, which protrudes above the surface of the first insulating dielectric layer structure formed in step D, is smoothed using chemical mechanical polishing. In this method, a mask 6 is placed on the photoresist before etching to ensure that the non-grooved portions are not etched.

[0063] The methods used in Examples 1-3 are all existing technologies in the field.

[0064] Methods for suppressing eddy current loss in bulk acoustic magnetoelectric antennas: The method for suppressing bulk eddy current in a magnetostrictive layer involves inserting an insulating dielectric layer along the thickness direction (z-axis direction), as shown in the attached... Figure 3 As shown; the method for suppressing surface eddy currents in the magnetostrictive layer involves inserting an insulating dielectric layer along the width direction (y-axis direction), as illustrated in the attached figure. Figure 4 As shown; the overall eddy current suppression method in the magnetostrictive layer involves simultaneously inserting an insulating dielectric layer along both the thickness direction (z-axis direction) and the width direction (y-axis direction), as illustrated in the attached figure. Figure 5 As shown.

[0065] The magnetic material in the magnetostrictive layer is an FeGaB thin film with a thickness of 1 μm and a surface area of ​​100 μm × 100 μm.

[0066] The conductivity of the insulating dielectric layer is in the range of 0-100 S / m, such as Al2O3, Si3N4, and AlN.

[0067] The number of insulating dielectric layers inserted along the thickness direction and the width direction are 3×3, respectively.

[0068] The volume eddy current suppression method inserts an insulating dielectric layer with a thickness of 5-30 nm along the thickness direction, and the number of separation layers is 3.

[0069] The surface eddy current suppression method involves inserting an insulating dielectric layer with a width of 5-100 nm along the width direction, with three separating layers. (See attached image.) Figure 6 As shown.

[0070] The insertion of the insulating dielectric layer along the width direction involves etching a central groove using photolithography, followed by filling the insulating dielectric layer using physical vapor deposition. The photolithography process employs reactive ion etching.

[0071] The following is in conjunction with the appendix Figure 6 Detailed description of the embodiments of the present invention:

[0072] Figure 6 This is a process flow diagram for the eddy current suppression structure.

[0073] Step 1: A FeGaB magnetic thin film with a thickness of 500 nm is deposited on the upper electrode of the bulk acoustic resonator using magnetron sputtering.

[0074] Step 2: Deposit an Al2O3 insulating layer on the FeGaB magnetic thin film using magnetron sputtering. The thickness of the Al2O3 insulating layer is 5-30 nm.

[0075] Step 3: Deposit a FeGaB magnetic film on the Al2O3 insulating layer, the magnetic film having a thickness of 500 nm.

[0076] Step 4: Apply a uniform layer of photoresist to the FeGaB magnetic thin film using a spin coater, followed by pre-baking, exposure, and development. The photoresist is a positive photoresist.

[0077] Step 5: Use dry etching to etch grooves into the magnetostrictive layer.

[0078] Step 6: Sputter an Al2O3 insulating layer into the magnetostrictive layer using magnetron sputtering.

[0079] Step 7: Remove the photoresist from the surface of the FeGaB magnetic thin film using a metal stripping process.

[0080] Step 8: Use chemical mechanical polishing to smooth the Al2O3 insulating layer 3 that protrudes above the surface of the FeGaB magnetic film.

[0081] To address the aforementioned technical deficiencies, this invention proposes a method and structure for suppressing eddy current loss in bulk acoustic wave magnetoelectric antennas. This method suppresses eddy current loss by inserting alternating transverse and longitudinal insulating media into the magnetostrictive layer. While ensuring the insulating media layer size is minimized, eddy current loss in the magnetic film is suppressed, and a magnetic film structure with a minimum-sized insulating media insertion for eddy current suppression is proposed. This structure effectively suppresses eddy current loss in the magnetostrictive layer while maintaining its good soft magnetic properties, improving the radiation efficiency of the magnetoelectric antenna and making the bulk acoustic wave magnetoelectric antenna more suitable for wireless communication applications. Based on the skin effect of the induced current in the magnetostrictive layer, this invention classifies eddy currents into bulk eddy currents and surface eddy currents, proposing a method that comprehensively considers both by inserting an insulating media layer for isolation, and constructing a magnetic film structure with a minimum-sized insulating media insertion for eddy current suppression, ensuring that eddy current loss reaches a minimum value.

[0082] This invention reduces bulk and surface eddy current losses by inserting alternating Al2O3 insulating layers along the thickness and width directions into the magnetostrictive layer, minimizing eddy current losses. This solves the problem of stress discontinuity and low radiation efficiency of magnetoelectric antennas caused by air gaps between the magnetostrictive layers in existing technologies. Using Al2O3 insulating layers as spacers improves the soft magnetic properties of FeGaB, effectively reducing its coercivity and increasing the sensitivity of the radiation region. Simulation analysis shows that this solution can effectively reduce eddy current losses by more than 65%, significantly improving the radiation efficiency of the magnetoelectric antenna.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vortex suppression structure comprising a magnetostrictive layer (1), characterized in that, It also includes an insulating dielectric layer disposed within the magnetostrictive layer (1) for interrupting eddy currents; A first insulating dielectric layer (2) is provided in the magnetostrictive layer (1) along its thickness direction and / or a second insulating dielectric layer (3) is provided in the magnetostrictive layer (1) along its width direction. At least one first insulating dielectric layer (2) is disposed within the magnetostrictive layer (1) along its thickness direction. The first insulating dielectric layer (2) consists of three parallel layers, each with a thickness of 5-100 nm. The magnetostrictive layer (1) is made of FeGaB thin film with a total thickness of 1 μm. The conductivity of the first insulating dielectric layer (2) ranges from 0 to 100 S / m. The first insulating dielectric layer (2) is made of any one or more of Al2O3, Si3N4 and AlN. At least one second insulating dielectric layer (3) is disposed within the magnetostrictive layer (1) along its width direction; The second insulating dielectric layer (3) consists of three parallel layers. The thickness of each second insulating dielectric layer (3) is 5-30 nm. The conductivity of the second insulating dielectric layer (3) ranges from 0-100 S / m. The second insulating dielectric layer (3) is made of one or more of Al2O3, Si3N4 and AlN.

2. The vortex suppression structure of claim 1, wherein At least one first insulating dielectric layer (2) is provided in the magnetostrictive layer (1) along its thickness direction, and at least one second insulating dielectric layer (3) is provided in the magnetostrictive layer (1) along its width direction. The first insulating dielectric layer (2) and the second insulating dielectric layer (3) are provided at intervals.

3. A magnetoelectric antenna comprising an upper electrode, characterized in that It also includes the eddy current suppression structure according to any one of claims 1-2, wherein the eddy current suppression structure is disposed on the upper electrode.

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