Laminated inductor and preparation method and application thereof

Abstract

The invention provides a laminated inductor and a preparation method and application thereof. The laminated inductor comprises a base body, an inner electrode embedded in the base body, an outer electrode connected with the side end of the base body and a magnetic conductive layer embedded in the laminated inductor. The outer electrode comprises a lead-in outer electrode and a lead-out outer electrode, and the inner electrode comprises a middle electrode arranged in the magnetic conductive layer, and a first lead-out electrode and a second lead-out electrode which are respectively connected with the top and the bottom of the middle electrode; and the first extraction electrode and the second extraction electrode respectively penetrate through a through groove formed in the side surface of the magnetic conductive layer and are electrically contacted with the extraction outer electrode and the introduction outer electrode. According to the laminated inductor, mutual interference between an external circuit and the inductor winding can be effectively reduced, signal integrity and transmission efficiency are improved, the system failure rate and the risk of performance reduction are reduced, and the preparation method is simple and suitable for commercial application.

Description

Technical Field

[0001] The invention belongs to the technical field of inductor components and relates to a laminated inductor and a preparation method and application thereof. Background Art

[0002] Due to the increasing complexity of modern circuit system design, the market's functional requirements for inductors are becoming more and more diverse, and different circuit designs and application scenarios may require different inductance values ​​and characteristics. In electronic devices, especially in mobile devices and wireless sensor networks with increasing miniaturization and integration requirements, mutual interference between electronic components has become an increasingly concerning issue.

[0003] Anti-interference inductors are inductors that use a layer of magnetic conductive material to reduce external electromagnetic interference and prevent internal magnetic field leakage. Magnetic conductive materials can effectively isolate the inductor windings from external electromagnetic fields, thereby reducing the impact of external interference on the inductor and preventing the magnetic field generated by the inductor from interfering with other circuit parts; at the same time, anti-interference inductors can effectively filter noise and interference, thus helping to maintain signal integrity and stability, especially in high-frequency applications. Anti-interference inductors can improve the stability and performance of the entire electronic device, reduce failures or performance degradation caused by electromagnetic interference, and help ensure the stable operation of electronic systems in complex environments by reducing electromagnetic interference and improving signal integrity.

[0004] For example, CN218769059U discloses an inductor with anti-interference function, including an inductor structure, an anti-interference component is arranged on the outside of the inductor structure, and the shielding cover can be installed inside the anti-interference shell through the setting of a limit plate, an anti-magnetic plate, a connecting column, a shielding cover, a positioning groove, a connecting rod, a connecting spring, a positioning column and an anti-interference shell. At the same time, the inductor structure can be subjected to anti-interference treatment to avoid electromagnetic influence on the normal use of the inductor structure.

[0005] However, the above-mentioned anti-interference inductor preparation method is complicated, which greatly increases the size of the original inductor and has limited magnetic shielding effect on high-inductance inductor devices, which is not conducive to commercial application. As a non-winding inductor, the stacked inductor has significant advantages over the traditional winding inductor, such as compact structure, no mutual interference and no directionality. Therefore, how to make a highly stable, high-inductance anti-interference stacked inductor under the existing material performance and size conditions is a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a laminated inductor and its preparation method and application. The laminated inductor provided by the present invention, by embedding the magnetic conductive layer into the laminated inductor and surrounding the middle electrode, effectively changes the distribution of the electromagnetic field, reduces the influence of external electromagnetic waves on the inductor winding, and prevents external noise from entering the inductor; especially in high-speed and high-frequency applications, it can effectively reduce signal distortion, improve signal integrity and transmission efficiency, and ensure the accuracy of data transmission; at the same time, it can also suppress the interference of the magnetic field generated by the inductor on the surrounding circuits, reduce the system failure rate and the risk of performance degradation, thereby improving the reliability and stability of the overall equipment; and the laminated inductor preparation method provided by the present invention is simple and suitable for commercial applications.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a stacked inductor, comprising a substrate, an inner electrode buried in the substrate, an outer electrode connected to a side end of the substrate, and a magnetic conductive layer embedded in the stacked inductor; the outer electrode comprises an introduction outer electrode and an extraction outer electrode, the inner electrode comprises an intermediate electrode arranged inside the magnetic conductive layer and a first extraction electrode and a second extraction electrode respectively connected to a top and a bottom of the intermediate electrode, the first extraction electrode and the second extraction electrode respectively pass through a through groove opened on a side surface of the magnetic conductive layer to electrically contact the extraction outer electrode and the introduction outer electrode.

[0009] In the present invention, by embedding a magnetic conductive layer surrounding the middle electrode in the laminated inductor, the distribution of the electromagnetic field can be effectively changed, the influence of external electromagnetic waves on the inductor winding can be reduced, and external noise can be prevented from entering the inductor; at the same time, the interference of the magnetic field generated by the inductor itself on the surrounding circuit can be suppressed, and the risk of system failure rate and performance degradation can be reduced, thereby improving the reliability and stability of the overall equipment; and, the present invention arranges the magnetic conductive layer inside the laminated inductor, avoiding a large area of ​​the magnetic conductive layer being exposed in the circuit, which can effectively prevent the phenomenon of short circuit due to contact between the magnetic conductive layer and external metal, thereby greatly improving safety.

[0010] As a preferred technical solution of the present invention, the shape of the magnetic conductive layer includes a rectangular parallelepiped or a curved body with the through grooves opened on the side.

[0011] As a preferred technical solution of the present invention, the center of the magnetic conductive layer coincides with the center of the laminated inductor.

[0012] The vertical distance from the center to the outer wall of the magnetic conductive layer is x times the vertical distance from the center to the edge of the middle electrode, and the vertical distance from the center to the outer wall of the laminated inductor is y times the vertical distance from the center to the edge of the middle electrode, x≥1.3, y≥1.1x, for example, x=1.3, y=1.5, x=1.4, y=1.7, x=1.5, y=2.0, x=1.6, y=2.3, x=1.7, y=2.6 or x=1.8, y=2.9, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] In the present invention, x and y both refer to the proportional relationship of the vertical distance in the same direction. By adjusting the distance between the magnetic conductive layer and the middle electrode and the outer electrode, the anti-interference effect can be further improved, and the safety can be further improved.

[0014] The wall thickness of the magnetic conductive layer is 5% to 10% of the maximum vertical distance from the center to the edge of the intermediate electrode, such as 5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0015] In the present invention, the thickness of the magnetic conductive layer can be adjusted according to the size of the inductor, so that the obtained laminated inductor can better balance the inductance value, anti-interference performance and safety performance.

[0016] As a preferred technical solution of the present invention, the lead-out electrode is a T-shaped thin sheet, which includes an integrally formed contact portion and a connecting portion, the side surface of the contact portion is in electrical contact with the external electrode, and a through hole is provided at the end of the connecting portion.

[0017] The contact portion of the extraction electrode is connected to the external electrode at multiple surfaces.

[0018] The first lead-out electrode and the second lead-out electrode are mirror-image structures.

[0019] The connection portion of the extraction electrode passes through the through groove.

[0020] Taking the width direction of the lead-out electrode connecting portion as the horizontal direction, the length of the through groove along the horizontal direction is 3 to 5 times the width of the lead-out electrode connecting portion, and the length of the through groove along the vertical and horizontal directions is 3 to 5 times the thickness of the lead-out electrode connecting portion, for example, 3.0 times, 3.5 times, 4.0 times, 4.5 times or 5.0 times, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] In the present invention, by adjusting the size of the through slot, a better balance among the three aspects of inductance, anti-interference effect and safety can be achieved.

[0022] As a preferred technical solution of the present invention, the material of the magnetic conductive layer includes metal.

[0023] The material of the magnetic conductive layer includes copper or silver.

[0024] As a preferred technical solution of the present invention, the intermediate electrode comprises a stacked spiral metal layer with the same rotation direction, and a through hole is respectively provided at the head end and the tail end of the spiral metal layer.

[0025] Adjacent spiral metal layers are connected via through-hole columns connected to the through-holes, and the spiral metal layer at the top and the spiral metal layer at the bottom are mirror-image structures.

[0026] The spiral metal layer at the top is connected to the through hole on the first lead-out electrode through a through hole column located at the head end of the spiral metal layer, and the spiral metal layer at the bottom is connected to the through hole on the second lead-out electrode through a through hole column located at the head end of the spiral metal layer.

[0027] The structure of the spiral metal layer includes an elliptical spiral structure.

[0028] In a second aspect, the present invention provides a method for preparing the multilayer inductor according to the first aspect, the method comprising:

[0029] (1) Grooves are formed on the ferrite diaphragm, and a metal conductor is printed in each groove as an inner electrode using a screen printing process;

[0030] (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying the adhesive to obtain a substrate;

[0031] (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor;

[0032] (4) Cutting along the periphery of the inner electrode to form a laminated inductor body, and exposing a portion of the inner electrode on both sides of the inductor body;

[0033] (5) Heating and keeping the inductor body warm to complete the debinding, and then sintering to fully solidify it;

[0034] (6) Chamfer the sintered semi-finished product and electroplate the outer electrodes on the exposed inner electrodes on both sides of the laminated inductor body.

[0035] The preparation method provided by the present invention only needs to embed a magnetic conductive layer during the preparation process of the stacked inductor, so as to improve the signal integrity and transmission efficiency in high-speed and high-frequency applications, reduce the risk of system failure rate and performance degradation, and improve the reliability and stability of the overall equipment; and the preparation method is simple and suitable for commercial applications.

[0036] As a preferred technical solution of the present invention, holes are punched at the beginning and the end of the groove, and a metal conductor is printed in the hole using a screen printing process to form a through-hole column.

[0037] The number of the ferrite diaphragms is at least two, such as 2, 3, 4, 5, 6, 7 or 8, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] The ferrite diaphragms are stacked and subjected to warm water isostatic pressing to obtain a laminate.

[0039] The inner electrodes on two adjacent ferrite diaphragms are connected through the through-hole column.

[0040] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0041] (1) grooves are formed on at least two ferrite diaphragms, holes are punched at the beginning and end of each groove, a metal conductor is printed in each groove as an inner electrode by a screen printing process, and a metal conductor is printed in each hole to form a through-hole column;

[0042] (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying it, then stacking the at least two ferrite diaphragms, connecting the inner electrodes on each ferrite diaphragm through the through-hole column, and then performing warm water isostatic pressing to obtain a laminate;

[0043] (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor;

[0044] (4) cutting along the periphery of the inner electrode to form at least two laminated inductor bodies, and exposing a portion of the inner electrode on both sides of each inductor body;

[0045] (5) heating and keeping warm at least two inductor bodies to complete debinding, and then sintering to fully solidify them;

[0046] (6) The sintered semi-finished product is chamfered and external electrodes are electroplated on the exposed internal electrodes on both sides of each laminated inductor body.

[0047] In a third aspect, the present invention further provides an application of the multilayer inductor as described in the first aspect in a high-frequency circuit.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The laminated inductor provided by the present invention, by embedding the magnetic conductive layer inside the laminated inductor and surrounding the middle electrode, effectively changes the distribution of the electromagnetic field, reduces the influence of external electromagnetic waves on the inductor winding, and prevents external noise from entering the inductor. Especially in high-speed and high-frequency applications, it can effectively reduce signal distortion, improve signal integrity and transmission efficiency, and ensure the accuracy of data transmission; at the same time, it can also suppress the interference of the magnetic field generated by the inductor on the surrounding circuits, reduce the system failure rate and the risk of performance degradation, thereby improving the reliability and stability of the overall equipment; and the laminated inductor provided by the present invention is simple to prepare the method, which is suitable for commercial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of the structure of the multilayer inductor provided in Example 1.

[0051] Figure 2 It is a schematic diagram of the structure of the magnetic conductive layer provided in Example 1.

[0052] Figure 3 This is a first structural schematic diagram of the intermediate electrode provided in Example 1.

[0053] Figure 4 This is a second structural schematic diagram of the intermediate electrode provided in Example 1.

[0054] Figure 5 It is a schematic diagram of the structure of the first lead-out electrode provided in Example 1.

[0055] Figure 6 It is a schematic diagram of the structure of the second lead-out electrode provided in Example 1.

[0056] Figure 7 3 is a performance curve diagram of the multilayer inductor provided in Example 1.

[0057] In the figure:

[0058] 1-substrate; 2-magnetic conductive layer; 3-introduction external electrode; 4-extraction external electrode; 5-intermediate electrode; 6-first extraction electrode; 7-second extraction electrode; 8-through groove; 9-through hole column; 10-contact part; 11-connection part. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0061] Example 1

[0062] This embodiment provides a stacked inductor, such as Figure 1 As shown, the shape of the multilayer inductor is a rectangular parallelepiped, including a substrate 1, an inner electrode buried in the substrate, an introduction external electrode 3 and an extraction external electrode 4 connected to both side ends of the substrate, and a magnetic conductive layer 2 embedded in the multilayer inductor; the inner electrode includes an intermediate electrode 5 arranged on the inner side of the magnetic conductive layer and a first extraction electrode 6 and a second extraction electrode 7 respectively connected to the top and bottom of the intermediate electrode, and the first extraction electrode 6 and the second extraction electrode 7 respectively pass through a through groove 8 opened on the side of the magnetic conductive layer to electrically contact the extraction external electrode 4 and the introduction external electrode 3.

[0063] The specific structure of the magnetic conductive layer is as follows: Figure 2 As shown; the specific structure of the intermediate electrode is as follows Figure 3 and Figure 4 As shown, it includes elliptical spiral metal layers stacked and rotating in the same direction, adjacent spiral metal layers are connected by through-hole columns 9, the spiral metal layer at the top and the spiral metal layer at the bottom are mirror images, and are connected to the through holes on the first lead-out electrode 6 and the second lead-out electrode 7 respectively through the through-hole columns 9 located at the head end of the spiral metal layer; the specific structures of the first and second lead-out electrodes are shown in Figure 5 and Figure 6 As shown, it includes an integrally formed contact portion 10 and a connecting portion 11 , and a side surface of the contact portion 10 is in electrical contact with an external electrode.

[0064] Among them, taking the outer wall of the stacked inductor as the standard, the size of the stacked inductor is 2.0mm×1.2mm×1.0mm, the overall size of the spiral metal layer is 1.1mm×0.7mm×0.6mm, the number of layers is 4, the number of coil turns is 4, the coil width is 50μm, and the wire thickness is 20μm; the material of the magnetic conductive layer is copper, and taking the outer wall of the magnetic conductive layer as the standard, the size of the magnetic conductive layer is 1.7mm×1.0mm×0.9mm, and the wall thickness is 0.03mm; the width of the lead-out electrode connecting part is 0.2mm, the thickness of the lead-out electrode is 0.05mm, and the size of the through groove is 0.8mm×0.2mm×0.03mm.

[0065] The preparation method is as follows:

[0066] (1) Prepare four ferrite diaphragms.

[0067] (2) A groove is formed on each ferrite diaphragm, and a hole is punched at the bottom of each groove to facilitate the subsequent connection between metal layers.

[0068] (3) A metal conductor is printed in each groove as an electrode by a silk-screen printing process. The metal conductor before curing is preferably a silver paste. The single-layer inner electrode includes a metal layer and a through-hole column. The surface of the metal layer is printed to form an electrode pattern, and the punched area is printed to form a through-hole column.

[0069] (4) Glue spraying: Use a diluted adhesive liquid to spray the printed electrode surface of the single-layer inner electrode and dry it to solidify the liquid silver paste for subsequent operations.

[0070] (5) The four ferrite diaphragms are stacked and pressed together in a spiral direction so that the inner electrodes on each two adjacent ferrite diaphragms are connected one by one to form a laminate.

[0071] (6) After four ferrite diaphragms are stacked and initially fixed, they are made into a laminate under warm water isostatic pressing to initially fix several layers of internal electrodes.

[0072] (8) After the laminate is completed, a metal magnetic conductor with a through slot on the side is embedded. The slot hole should be placed away from the silver paste layer to prevent short circuit. Cut along the inner electrode to form a single laminated inductor body, and expose part of the inner electrode on both sides of each inductor body. After the ferrite film is stacked, the electrodes in the layers are connected one by one to form several connected laminated inductor bodies in the laminate. Cut along the body to expose part of the inner electrode on both sides of each body, which is convenient for the subsequent attachment of external electrodes.

[0073] (8) Debinding and sintering: The main body is heated and then kept warm for a certain period of time to complete the debinding, and then sintered to make it completely solidified.

[0074] (9) The sintered semi-finished product is chamfered, and the exposed inner electrodes on both sides of each single-body laminated inductor body are silver-coated and then electroplated with metal outer electrodes.

[0075] Example 2

[0076] This embodiment provides a multilayer inductor, the structure of which is the same as that of the first embodiment.

[0077] Among them, taking the outer wall of the stacked inductor as the standard, the size of the stacked inductor is 2.5mm×2.0mm×1.0mm, the overall size of the spiral metal layer is 1.1mm×0.7mm×0.6mm, the number of layers is 4, the number of coil turns is 4, the coil width is 50μm, and the wire thickness is 20μm; the material of the magnetic conductive layer is copper, and taking the outer wall of the magnetic conductive layer as the standard, the size of the magnetic conductive layer is 2.2mm×1.8mm×0.9mm, and the wall thickness is 0.03mm; the width of the lead-out electrode connecting part is 0.2mm, the thickness of the lead-out electrode is 0.05mm, and the size of the through groove is 0.8mm×0.2mm×0.03mm.

[0078] The preparation method is consistent with that in Example 1.

[0079] Example 3

[0080] This embodiment provides a multilayer inductor. The shape of the multilayer inductor is a rectangular parallelepiped, the shape of the magnetic conductive layer is an ellipsoid, and the rest of the structure is the same as that of the first embodiment.

[0081] Among them, taking the outer wall of the stacked inductor as the standard, the size of the stacked inductor is 3.2mm×2.5mm×1.0mm, the overall size of the spiral metal layer is 1.1mm×0.7mm×0.6mm, the number of layers is 4, the number of coil turns is 4, the coil width is 50μm, and the wire thickness is 20μm; the material of the magnetic conductive layer is silver, and taking the outer wall of the magnetic conductive layer as the standard, the size of the magnetic conductive layer is 2.9mm×2.2mm×0.9mm, and the wall thickness is 0.03mm; the width of the lead-out electrode connecting part is 0.2mm, the thickness of the lead-out electrode is 0.05mm, and the size of the through groove is 0.8mm×0.2mm×0.03mm.

[0082] The preparation method is consistent with that in Example 1.

[0083] Example 4

[0084] The difference between this embodiment and embodiment 1 is that the thickness of the magnetic conductive layer in this embodiment is 0.015 mm.

[0085] The rest of the preparation methods and parameters were consistent with those in Example 1.

[0086] Example 5

[0087] The difference between this embodiment and embodiment 1 is that the thickness of the magnetic conductive layer in this embodiment is 0.07 mm.

[0088] The rest of the preparation methods and parameters were consistent with those in Example 1.

[0089] Comparative Example 1

[0090] The difference between this embodiment and embodiment 1 is that no magnetic conductive layer is provided.

[0091] The rest of the preparation methods and parameters were consistent with those in Example 1.

[0092] Performance Testing

[0093] The performance of the laminated inductors provided in Examples 1-5 and Comparative Example 1 was tested under the test condition of 1 MHz. The test results are shown in Table 1:

[0094] Table 1

[0095]

[0096] Depend on Figure 7 From the comparison between Examples 1 to 3 in Table 1 and Comparative Example 1, it can be seen that by providing magnetic conductive layers of different sizes in laminated inductors of different sizes, while achieving an anti-interference effect, the inductance value and quality factor of the inductor are not significantly affected, compared with the laminated inductor without the magnetic conductive layer. This also shows that the laminated inductor provided by the present invention can effectively reduce the mutual interference between the external circuit and the inductor winding without affecting the inductance value and its quality factor, improve the integrity and transmission efficiency of the signal, reduce the risk of system failure rate and performance degradation, and the preparation method is simple and suitable for commercial applications.

[0097] From the comparison between Examples 4-5 and Example 1 in Table 1, it can be seen that the thickness of the magnetic conductive layer will affect the inductance of the laminated inductor. When the wall thickness of the magnetic conductive layer is within the range of 5%-10% of the maximum vertical distance from the center to the edge of the middle electrode, a better balance between the inductance value and the anti-interference effect can be achieved. In practical applications, different magnetic conductive layer thicknesses can be selected as needed.

[0098] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A multilayer inductor, characterized in that: The laminated inductor comprises a substrate, an inner electrode buried in the substrate, an outer electrode connected to a side end of the substrate, and a magnetic conductive layer embedded in the laminated inductor; The external electrode includes an introduction external electrode and an extraction external electrode, the internal electrode includes an intermediate electrode arranged inside the magnetic conductive layer and a first extraction electrode and a second extraction electrode respectively connected to the top and bottom of the intermediate electrode, the first extraction electrode and the second extraction electrode respectively pass through the through grooves opened on the side of the magnetic conductive layer to electrically contact the extraction external electrode and the introduction external electrode.

2. The multilayer inductor according to claim 1, characterized in that: The shape of the magnetic conductive layer includes a rectangular parallelepiped or a curved body with the through grooves opened on the side.

3. The multilayer inductor according to claim 1, characterized in that: The center of the magnetic conductive layer coincides with the center of the laminated inductor; The vertical distance from the center to the outer wall of the magnetic conductive layer is x times the vertical distance from the center to the edge of the middle electrode, and the vertical distance from the center to the outer wall of the laminated inductor is y times the vertical distance from the center to the edge of the middle electrode, x≥1.3, y≥1.1x; The wall thickness of the magnetic conductive layer is 5% to 10% of the maximum vertical distance from the center to the edge of the middle electrode.

4. The multilayer inductor according to claim 1, characterized in that: The lead-out electrode is a T-shaped thin sheet, and the T-shaped thin sheet includes an integrally formed contact portion and a connecting portion, the side surface of the contact portion is in electrical contact with the external electrode, and a through hole is provided at the end of the connecting portion; The contact portion of the extraction electrode is connected to the external electrode on multiple surfaces; The first lead-out electrode and the second lead-out electrode are mirror-image structures; The connecting portion of the lead-out electrode passes through the through groove; Taking the width direction of the lead-out electrode connecting portion as the horizontal direction, the length of the through groove along the horizontal direction is 3 to 5 times the width of the lead-out electrode connecting portion, and the length of the through groove along the vertical and horizontal directions is 3 to 5 times the thickness of the lead-out electrode connecting portion.

5. The multilayer inductor according to claim 1, characterized in that: The material of the magnetic conductive layer includes metal; The material of the magnetic conductive layer includes copper or silver.

6. The multilayer inductor according to claim 1, characterized in that: The intermediate electrode comprises a stacked spiral metal layer with the same rotation direction, and a through hole is respectively provided at the head end and the tail end of the spiral metal layer; The adjacent spiral metal layers are connected via a through-hole column connected to the through-hole, and the spiral metal layer at the top and the spiral metal layer at the bottom are mirror-image structures; The spiral metal layer at the top is connected to the through hole on the first lead-out electrode through a through hole column located at the head end of the spiral metal layer, and the spiral metal layer at the bottom is connected to the through hole on the second lead-out electrode through a through hole column located at the head end of the spiral metal layer; The structure of the spiral metal layer includes an elliptical spiral structure.

7. A method for preparing a multilayer inductor as claimed in claim 1, characterized in that: The preparation method comprises: (1) Grooves are formed on the ferrite diaphragm, and a metal conductor is printed in each groove as an inner electrode using a screen printing process; (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying the adhesive to obtain a substrate; (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor; (4) Cutting along the periphery of the inner electrode to form a laminated inductor body, and exposing a portion of the inner electrode on both sides of the inductor body; (5) Heating and keeping the inductor body warm to complete the debinding, and then sintering to fully solidify it; (6) Chamfer the sintered semi-finished product and electroplate the outer electrodes on the exposed inner electrodes on both sides of the laminated inductor body.

8. The method for preparing a multilayer inductor according to claim 7, characterized in that: Drill holes at the beginning and the end of the groove, and print metal conductors in the holes using a screen printing process to form through-hole columns; The number of the ferrite diaphragms is at least two; The ferrite diaphragms are stacked and subjected to warm water isostatic pressing to obtain a laminate; The inner electrodes on two adjacent ferrite diaphragms are connected through the through-hole column.

9. The method for preparing a multilayer inductor according to claim 7, characterized in that: The preparation method comprises: (1) grooves are formed on at least two ferrite diaphragms, holes are punched at the beginning and end of each groove, a metal conductor is printed in each groove as an inner electrode by a screen printing process, and a metal conductor is printed in each hole to form a through-hole column; (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying it, then stacking the at least two ferrite diaphragms, connecting the inner electrodes on each ferrite diaphragm through the through-hole column, and then performing warm water isostatic pressing to obtain a laminate; (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor; (4) cutting along the periphery of the inner electrode to form at least two laminated inductor bodies, and exposing a portion of the inner electrode on both sides of each inductor body; (5) heating and keeping warm at least two inductor bodies to complete debinding, and then sintering to fully solidify them; (6) The sintered semi-finished product is chamfered and external electrodes are electroplated on the exposed internal electrodes on both sides of each laminated inductor body.

10. Use of the multilayer inductor according to any one of claims 1 to 6 in a high-frequency circuit.

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