CN115727715A - Chiral wave absorber based on magnetic medium and preparation method thereof - Google Patents
Chiral wave absorber based on magnetic medium and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a chiral wave absorber based on a magnetic medium and a preparation method thereof. Firstly, arranging a metal coil on the surface of ferrite ceramic to obtain a chiral wave-absorbing element; and then fixing the plurality of chiral wave absorbing elements on the metal bottom plate according to a certain arrangement mode to obtain the chiral wave absorber. The metal coil is arranged in a mode that the metal coil is wound on the surface of the ferrite ceramic; or, firstly etching a coil-shaped groove on the surface of the ferrite ceramic, and then spraying or scraping metal electrode materials in the groove to form the metal coil. The chiral wave absorber based on the magnetic medium has excellent P-band low-frequency wave absorbing performance, good high-temperature resistance and flexible performance adjustability, and also has the process characteristic of simple construction operation.
Description
Technical Field
The invention belongs to the technical field of wave absorbers and wave absorbing materials, and particularly relates to a chiral wave absorber based on a magnetic medium and a preparation method thereof.
Background
With the rapid development of modern electronic information technology, radar detection means are continuously improved, and the battlefield viability of future war land, sea, air and space weaponry is greatly threatened. The stealth technology is an effective means for improving the survival capability and the operational capability of weaponry on a battlefield, and becomes a hot spot pursued in the military field, wherein the wave-absorbing material is more widely concerned, and the spelling of the stealth technology of each country is actually competition of the wave-absorbing material. In recent years, wave-absorbing materials of different systems are developed rapidly, stealth performance is gradually improved, and the wave-absorbing materials are widely applied in the military field. However, it is worth mentioning that the development and improvement of the low-frequency stealth performance are limited by the wave-absorbing material, and especially the wave-absorbing performance of the P-band meets the bottleneck problem and is difficult to be greatly improved. The wave-absorbing material of the low-frequency P wave band becomes a research hotspot in the next years and has very important significance.
At present, the most researched low-frequency wave-absorbing materials mainly comprise amorphous alloy, ferrite wave-absorbing materials, metal micro powder and other traditional wave-absorbing materials, and the materials have high magnetic conductivity and good wave-absorbing performance in a low-frequency band. However, in a lower P band, the thickness of the wave-absorbing material is inevitably increased to have better performance, and the thickness and weight of the material cannot be infinitely increased due to the limitation of application scenarios, so that the conventional wave-absorbing material has the defects of poor performance and poor controllability in the P band.
The patent ' a magnetic broadband electromagnetic wave-absorbing metamaterial ' (202010318043. X) ' invents an array wave-absorbing metamaterial, the scheme uses a magnetic powder material, ceramic treatment is not carried out, and the low-frequency magnetic conductivity is not too high; in addition, in the scheme, electrode materials are not machined on the surface of the magnetic material, and key electromagnetic coupling loss is lacked, so that the scheme only aims at a 2-18GHz frequency band, and difficult P wave band research is not carried out. The patent 'a broadband metamaterial wave absorber' (201910225972.3) invents a wave-absorbing metamaterial, and the scheme also adopts an array structure, but does not use a magnetic medium material, but adopts a metamaterial combination of a dielectric material and a metal pattern, and aims at the terahertz frequency band. The patent 'a multilayer ultra wide band absorber of electric loss material and magnetic material complex' (201910769579.0) invents a multilayer absorber of combination electric and magnetic loss material, and this scheme design is complicated, and the number of layers is more, leads to overall thickness thicker, sees P wave band performance poor from the performance.
The prior art is more specific to the frequency range of 2-18GHz, and has less research on 0.3-1GHz (P waveband), although part of the technology relates to the frequency range below 1GHz, and a magnetic loss medium is also used, and the thickness is thicker, the magnetic loss of the material is obviously lower, so that the low-frequency wave-absorbing performance is poor, and particularly, the P waveband wave-absorbing performance is difficult to effectively improve. In addition, in the prior art, the target frequency band needs to be designed by means of designing complex patterns or shapes, the structure is complex, and the construction difficulty is high.
Disclosure of Invention
The invention aims to provide a chiral wave absorber based on a magnetic medium and a preparation method thereof.
In order to achieve the purpose, the invention provides the following technical scheme:
in the first aspect, the invention provides a preparation method of a chiral wave absorber based on a magnetic medium, which mainly comprises two steps, wherein the first step is used for preparing a chiral wave absorbing element, and the second step is used for constructing the wave absorber. The method comprises the following steps:
arranging a metal coil on the surface of the ferrite ceramic to obtain a chiral wave-absorbing element;
and fixing a plurality of chiral wave absorbing elements on a metal bottom plate according to a certain arrangement mode to obtain the chiral wave absorber.
Preferably, the metal coil is arranged on the surface of the ferrite ceramic in a manner of one of the following:
the first mode is as follows: winding a metal coil on the surface of the ferrite ceramic, for example, winding a metal coil or an enameled wire coil on the surface of the rectangular ferrite ceramic in a direction perpendicular to the length direction;
the second mode is as follows: firstly, etching a coil-shaped groove on the surface of ferrite ceramic, and then spraying or blade-coating a metal electrode material in the groove to form a metal coil.
Preferably, the ferrite ceramic is prepared by the following method:
and (3) putting the ferrite powder into a specific mould, putting the special mould into a press for compression molding, and then sintering the special mould at a high temperature by adopting a high-temperature furnace to prepare the ferrite ceramic.
Preferably, the ferrite ceramic may be in the shape of a rectangular parallelepiped, a cylinder, or the like. When the metal coil is wound on the surface of the ferrite ceramic, the metal coil is wound on the surface of the ferrite ceramic in a direction perpendicular to the longitudinal direction.
Preferably, the fixing the plurality of chiral wave absorbing elements on the metal base plate according to a certain arrangement mode to obtain the chiral wave absorber, includes:
patterns are printed on a metal base plate (namely a reflecting layer), and a plurality of chiral wave absorbing elements are fixed on the metal base plate in a gluing mode according to the patterns in a certain arrangement mode, so that the chiral wave absorber with excellent low-frequency wave absorbing performance is obtained.
Preferably, the crystal form of the ferrite powder is one or more of spinel type, garnet type and magnetoplumbite type.
Preferably, the sintering temperature of the ferrite ceramic is 850-1200 ℃, and the sintering time of the ferrite ceramic is 1-10 hours.
Preferably, when the ferrite ceramic is a cuboid ferrite ceramic, the length of the cuboid ferrite ceramic is 10-50mm, the width of the cuboid ferrite ceramic is 1-10mm, and the thickness of the cuboid ferrite ceramic is 1-5mm.
Preferably, the material of the metal coil is one of copper, silver, aluminum and enameled wire (such as gold enameled wire).
Preferably, the diameter of the enamel wire is 0.1-1mm.
Preferably, the winding manner of the metal coil is single-layer winding.
Preferably, the number of winding turns of the metal coil is 10 to 500.
Preferably, the chiral wave-absorbing elements are arranged in an equidistant and orderly manner, and the distance between the two chiral wave-absorbing elements is 1-10mm.
Preferably, the metal base plate is one of aluminum, iron, copper or a carbon material.
In a second aspect, the invention provides a chiral wave absorber based on a magnetic medium, which is prepared by the method.
The technical scheme of the invention has the following advantages:
according to the scheme provided by the invention, the chiral wave absorbing element is constructed by preparing the ferrite ceramic, and then the wave absorbing material is combined with the structural design in an array arrangement and combination mode to prepare the chiral wave absorber with enhanced magnetism. The chiral wave absorbing element in the invention is a wave absorbing structure body formed by spirally winding a coil on ferrite ceramic, so that the wave absorbing structure body has chiral characteristics. The wave absorber constructed by a plurality of chiral wave absorbing elements in an array form is called a chiral wave absorber. The wave absorber can generate strong electromagnetic coupling loss under an electromagnetic field due to the chiral characteristic, thereby being beneficial to enhancing the wave absorbing performance.
The magnetic ferrite in the wave absorbing element has the advantages of strong magnetic loss and high temperature resistance, the electromagnetic coupling loss is increased after the metal coil is wound on the surface, and the wave absorbing device is endowed with excellent low-frequency P-band wave absorbing performance after an array wave absorbing structure is constructed by orderly combination. Compared with the traditional wave-absorbing material form, the wave-absorbing material is prepared into the wave-absorbing elements in the scheme and then is combined with the array design, so that excellent performance is obtained, the larger bright spot is that the array structure is strong in designability, and the wave-absorbing elements and the array structure can be flexibly designed according to the application requirements of different scenes so as to meet the regulation and control requirements of various performances.
The wave absorber provided by the invention has the advantages of simple structure, simple and feasible preparation method, mature and stable process, convenience in construction, low production cost and capability of large-scale production.
Drawings
FIG. 1 is a flow chart of the steps for preparing the chiral wave absorber based on magnetic medium.
FIG. 2 is a graph showing the reflectance test curve of the chiral filter obtained in example 1, wherein the abscissa shows frequency in GHz and the ordinate shows reflectance in dB.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention shall be described in further detail with reference to the following detailed description and accompanying drawings.
The invention provides a chiral wave absorber based on a magnetic medium and a preparation method thereof. The method provided by the invention adopts the combination of high-temperature sintering technology and array structure design to prepare the chiral wave absorber with enhanced magnetism.
Specifically, a method for preparing a chiral wave absorber based on a magnetic medium according to an embodiment of the present invention is shown in fig. 1, and includes the following steps:
(1) The preparation method of the chiral wave-absorbing element comprises the following steps: and (2) putting a certain amount of ferrite powder into a specific mould, putting the special mould into a press for compression molding, then putting the special mould into a high-temperature furnace for high-temperature sintering for a certain time, cooling and demoulding to prepare the cuboid ferrite ceramic plate. And then winding a metal coil on the surface of the cuboid ferrite ceramic chip in the direction vertical to the length direction to prepare the chiral wave-absorbing element.
(2) The wave absorber preparation step: printing a checkered pattern on a metal base plate according to the size of the chiral wave-absorbing elements and the designed intervals, then pasting double-sided adhesive or brushing adhesive on all the wave-absorbing elements prepared in the step (1) in parallel with the base plate, and then pasting a plurality of chiral wave-absorbing units on the metal base plate at fixed intervals according to the patterns to obtain the chiral wave absorber.
In some preferred embodiments, the crystal form of the ferrite powder is one or more of spinel type, garnet type, and magnetoplumbite type.
In some preferred embodiments, the ferrite ceramic is sintered at a temperature of 850 to 1200 ℃ for a time of 1 to 10 hours.
In some preferred embodiments, when the ferrite ceramic is a rectangular parallelepiped ferrite ceramic, the length of the rectangular parallelepiped ferrite ceramic is 10 to 50mm, the width of the rectangular parallelepiped ferrite ceramic is 1 to 10mm, and the thickness of the rectangular parallelepiped ferrite ceramic is 1 to 5mm.
In some preferred embodiments, the material of the metal coil is one of copper, silver, aluminum, and enameled wire (e.g., gold enameled wire).
In some preferred embodiments, the enameled wire has a diameter of 0.1 to 1mm.
In some preferred embodiments, the metal coil is wound in a single layer.
In some preferred embodiments, the number of winding turns of the metal coil is 10 to 500.
In some preferred embodiments, the chiral wave-absorbing elements are arranged in an orderly manner at equal intervals, and the interval between two pieces is 1-10mm.
In some preferred embodiments, the metal base plate is one of aluminum, iron, copper, or carbon material.
When only ferrite ceramic is used and a coil is not wound, the wave-absorbing material lacks an electromagnetic coupling effect, so that the wave-absorbing performance is remarkably reduced due to weak loss; when the array structure is not formed, the P-band wave-absorbing performance of the single ferrite wave-absorbing material is also obviously reduced. According to the invention, the ferrite ceramic and the coil are combined to prepare the chiral wave-absorbing element, and the chiral wave-absorbing element is arrayed, so that the electromagnetic loss can be obviously improved, and the P-band wave-absorbing performance can be improved.
The wave absorber prepared by the invention not only has excellent low-frequency P-band wave absorbing performance, but also has good high-temperature resistance, and also has the advantages of thin thickness, flexible and adjustable performance, and the process characteristic of simple construction operation.
According to the invention, the ferrite is ceramized in a high-temperature sintering manner, so that the low-frequency magnetic loss characteristic is improved; electromagnetic cross coupling loss is realized through the simple and feasible process of winding the coil on the surface, and the wave absorbing performance of the P wave band is improved; the wave-absorbing bandwidth is adjusted by designing the size and the distance of the wave-absorbing elements.
The key points of the invention include:
1. in the invention, the ferrite is firstly ceramized, and then the chiral wave-absorbing element is prepared, so that the magnetic loss characteristic is improved to the greatest extent, and the low-frequency P-band wave-absorbing performance is improved.
2. Compared with the prior technical scheme, the ferrite ceramic has the characteristic of high temperature resistance and can be applied to high-temperature environments.
3. A metal coil is wound on the surface of ferrite ceramic, a chiral element is prepared, and under the action of an electromagnetic field, a dielectric medium induces magnetic loss and a magnetic medium induces electric loss to form electromagnetic coupling loss, so that the loss capacity of the wave absorber is further improved. The method is simple and effective.
4. The array structure of the invention is simple in design and strong in controllability of the wave absorption performance.
The chiral wave-absorbing element in the invention can be prepared by etching a coil-shaped groove on the surface of ferrite ceramic and then spraying or blade-coating a metal electrode material in the groove, besides the preparation method of winding a metal coil on the surface.
The ferrite ceramic of the invention can be prepared into a cuboid or a cylinder.
In one embodiment of the invention, the preparation method of the chiral wave absorber based on the magnetic medium comprises the following steps:
(1) 10g of ferrite powder is added into a die, then the die is placed into a press for compression molding, the ferrite sheet is taken out after demolding, and the steps are repeated to prepare 1000 identical samples. And (3) putting the pressed ferrite sheet into a high-temperature furnace, sintering for 4 hours at 1200 ℃, and taking out the ferrite ceramic after complete cooling. And winding a copper enameled wire with the diameter of 0.2mm in the length direction of the surface of the ferrite ceramic chip, wherein the number of turns is 60, and preparing the chiral wave-absorbing element with the size of 38mm multiplied by 8 mm.
(2) And (2) printing uniform lattice patterns on an aluminum plate with the side length of 1000mm, wherein the length of each lattice is 40mm, the width of each lattice is 10mm, brushing epoxy resin adhesive on one surface of each chiral wave-absorbing element prepared in the step (1), and then adhering the chiral wave-absorbing elements on a metal plate at fixed intervals according to the patterns to obtain the magnetic-enhanced chiral wave absorber. The reflectivity test curve of the chiral absorber prepared in this example is shown in fig. 2.
The particular embodiments of the present invention disclosed above are illustrative only and not intended to be limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all modifications and variations which may be apparent to those skilled in the art may be resorted to without departing from the spirit and scope of the invention. The invention should not be limited to the disclosure of the embodiments in the present specification, but the scope of the invention is defined by the appended claims.
Claims (10)
1. A preparation method of a chiral wave absorber based on a magnetic medium is characterized by comprising the following steps:
arranging a metal coil on the surface of the ferrite ceramic to obtain a chiral wave-absorbing element;
and fixing a plurality of chiral wave absorbing elements on a metal bottom plate according to a certain arrangement mode to obtain the chiral wave absorber.
2. The method of claim 1, wherein the metal coil is disposed on the surface of the ferrite ceramic in a manner selected from the group consisting of:
winding a metal coil on the surface of the ferrite ceramic;
firstly, etching a coil-shaped groove on the surface of the ferrite ceramic, and then spraying or blade-coating a metal electrode material in the groove to form the metal coil.
3. The method as claimed in claim 2, wherein the metal coil is wound on the surface of the ferrite ceramic in a single layer, and the number of winding turns is 10-500.
4. The method of claim 1, wherein the ferrite ceramic is prepared by filling ferrite powder into a specific mold, performing compression molding, and then performing high-temperature sintering; the crystal form of the ferrite powder is at least one of spinel type, garnet type and magnetoplumbite type; the sintering temperature of the ferrite ceramic is 850-1200 ℃, and the sintering time is 1-10 hours.
5. The method of claim 1, wherein the ferrite ceramic is a cuboid or cylinder; the length of the cuboid ferrite ceramic is 10-50mm, the width is 1-10mm, and the thickness is 1-5mm.
6. The method according to claim 1, wherein the fixing of the plurality of chiral absorbing elements on the metal substrate in a certain arrangement comprises: patterns are printed on the metal base plate, and the plurality of chiral wave absorbing elements are fixed on the metal base plate in a gluing mode according to the patterns to obtain the chiral wave absorber with excellent low-frequency wave absorbing performance.
7. The method according to claim 6, wherein the chiral wave absorbing elements are arranged in an equidistant and ordered manner, and the distance between two chiral wave absorbing elements is 1-10mm.
8. The method of claim 1, wherein the metal coil is made of one of copper, silver, aluminum and enameled wire; the diameter of the enameled wire is 0.1-1mm.
9. The method of claim 1, wherein the metal base plate is one of aluminum, iron, copper, or a carbon material.
10. A magnetic media-based chiral wavesucker prepared according to the method of any one of claims 1 to 9.
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