阅读说明：本技术 一种柔性电阻膜-金属复合型频率选择表面、其制备和应用 (flexible resistive film-metal composite frequency selective surface, preparation and application thereof ) 是由 江建军 贺云 缪灵 别少伟 黄泽 于 2019-08-16 设计创作，主要内容包括：本发明属于柔性FSS吸波结构领域,更具体地,涉及一种柔性电阻膜-金属复合型频率选择表面、其制备和应用。将表面印有频率选择表面图案的感光膜贴覆在柔性覆铜板上,依次进行曝光和显影,得到显影后的柔性覆铜版；对显影后的柔性覆铜板进行刻蚀,得到刻蚀后的柔性覆铜板；对刻蚀后的柔性覆铜板进行脱膜干燥处理；脱膜后获得具有铜质表面的频率选择表面图案；采用丝网印刷技术将导电碳浆从丝网印版的网孔中挤压至所述脱膜后的柔性覆铜板表面或背面,烧结固化后得到电阻膜；获得所述柔性电阻膜-金属复合型频率选择表面。本发明提出的制备方法操作简单,可以制作应用于曲面的大面积柔性电阻膜-金属复合型FSS。(the invention belongs to the field of flexible FSS wave-absorbing structures, and particularly relates to a flexible resistive film-metal composite frequency selective surface, and preparation and application thereof. Pasting a photosensitive film with a frequency selective surface pattern printed on the surface on a flexible copper-clad plate, and sequentially carrying out exposure and development to obtain a developed flexible copper-clad plate; etching the developed flexible copper clad laminate to obtain an etched flexible copper clad laminate; carrying out demoulding and drying treatment on the etched flexible copper-clad plate; obtaining a frequency selective surface pattern with a copper surface after demoulding; adopting a screen printing technology to extrude conductive carbon paste to the surface or the back of the stripped flexible copper-clad plate from meshes of a screen printing plate, and sintering and curing to obtain a resistance film; and obtaining the flexible resistive film-metal composite type frequency selection surface. The preparation method provided by the invention is simple to operate, and can be used for manufacturing the large-area flexible resistive film-metal composite FSS applied to the curved surface.)

1. A preparation method of a flexible resistive film-metal composite frequency selection surface is characterized by comprising the following steps:

S1: pasting a photosensitive film with a frequency selection surface pattern printed on the surface on a flexible copper-clad plate, and sequentially carrying out exposure and development to obtain a developed flexible copper-clad plate and expose a copper surface and the frequency selection surface pattern;

s2: etching the developed flexible copper clad laminate to obtain an etched flexible copper clad laminate; the etching is used for removing copper on the copper surface, exposing the surface of the copper-clad plate substrate layer, and simultaneously reserving a photosensitive film attached on the copper-clad plate, wherein the photosensitive film presents a preset frequency selection surface pattern;

s3: performing stripping and drying treatment on the etched flexible copper clad laminate to obtain a stripped flexible copper clad laminate; obtaining a frequency selective surface pattern with a copper surface after demoulding;

S4: adopting a screen printing technology to extrude conductive carbon paste to the surface or the back of the stripped flexible copper-clad plate from meshes of a screen printing plate, and sintering and curing to obtain a resistance film; the screen plate comprises a pre-designed resistive film pattern, and the flexible resistive film with the pre-designed pattern is prepared on the surface or the back surface of the stripped flexible copper-clad plate, so that the flexible resistive film-metal composite type frequency selection surface is obtained.

2. the preparation method according to claim 1, wherein the substrate layer material of the flexible copper clad laminate is glass fiber reinforced epoxy resin or polyimide.

3. the preparation method according to claim 1, wherein the thickness of the flexible copper clad laminate is 0.025 mm-0.8 mm, and the thickness of the copper clad laminate on the surface of the copper clad laminate is 0.01 mm-0.02 mm.

4. The preparation method according to claim 1, wherein the step S2 is to etch the developed flexible copper clad laminate by weak base solution, wherein the etching temperature is 40-60 ℃; the weak base solution is a sodium carbonate solution, and the concentration of the weak base solution is 30-60 g/L.

5. the method according to claim 1, wherein step S4 specifically comprises:

S401: placing the surface or the back of the stripped flexible copper clad laminate on a screen printing workbench in a horizontal mode, and exhausting air to fix the flexible copper clad laminate;

s402: placing the screen printing plate above the flexible copper-clad plate in an aligned manner with the flexible copper-clad plate, pouring conductive carbon slurry at one end, applying certain pressure to the carbon slurry part of the screen printing plate by using a scraper, moving towards the other end of the screen printing plate at a constant speed, and extruding the carbon slurry onto the flexible copper-clad plate from meshes of the screen printing plate by using the scraper in the moving process to obtain the flexible copper-clad plate coated with the conductive carbon slurry;

S403: and sintering and curing the flexible copper clad laminate coated with the conductive carbon paste, wherein the cured conductive carbon paste is the resistance film, the screen printing plate comprises a pre-designed resistance film pattern, and thus the flexible resistance film with the pre-designed pattern is prepared on the surface or the back of the stripped flexible copper clad laminate to obtain the flexible resistance film-metal composite frequency selection surface.

6. The production method according to claim 1, wherein the conductive carbon paste comprises a carbon material and a resin, the carbon material being one or more of carbon black, graphene and graphite; the resin is epoxy resin or polyamide resin; the conductive carbon paste is used for providing a certain square resistance for the flexible resistive film-metal composite type frequency selection surface, and the square resistance range is 20-1000 omega.

7. the preparation method according to claim 1, wherein the sintering and curing temperature is 150 ℃ to 200 ℃ and the time is 30min to 60 min.

8. the flexible resistive film-metal composite frequency selective surface prepared by the preparation method according to any one of claims 1 to 7.

9. Use of a flexible resistive film-metal composite frequency selective surface as claimed in claim 7 for the preparation of an electromagnetic wave absorbing device.

10. An electromagnetic wave absorbing device, characterized in that its functional layer comprises the flexible resistive film-metal composite frequency selective surface of claim 8.

Technical Field

The invention belongs to the field of flexible FSS wave-absorbing structures, and particularly relates to a flexible resistive film-metal composite frequency selective surface, and preparation and application thereof.

Background

A Frequency Selective Surface (FSS) is a periodic-effect device that has Selective reflection, absorption, or transmission functions for incident electromagnetic waves. Structurally, FSS is classified into a patch type and an aperture type, and exhibits band-stop and band-pass characteristics for electromagnetic waves, respectively. FSS is widely used in the microwave field because of its selective properties for incident electromagnetic waves.

In the technical field of electromagnetic wave absorption, the novel wave absorption structure based on the FSS can realize broadband absorption and can effectively absorb electromagnetic wave energy. In the field of electromagnetic shielding, a mobile phone may generate signal interference to a precision electronic device, and radio waves may interfere with a communication environment of an airport, so that it is necessary to reduce or even shield external electromagnetic waves. In the field of communications, the MIMO antenna technology is one of the core technologies of a mobile base station, and a half-wave antenna and a microstrip antenna are one of patch-type FSS.

In the traditional metal FSS wave absorber design, in order to realize broadband wave absorption, lumped devices such as a chip resistor, a chip inductor, a chip capacitor and the like are mostly welded, the production period of the preparation method is long, and the wave absorber has poor stability under extreme working conditions (such as the working temperature of the chip capacitor is lower than 100 ℃) because soldering tin and the devices cannot resist high temperature. On the other hand, in the traditional resistance film type FSS wave absorber design, the pure resistance film design is adopted, so that the working stability is improved relative to a metal type FSS wave absorber, but the impedance adjusting range of the wave absorber is relatively small, and the wave absorbing bandwidth is relatively reduced. Therefore, a novel wave absorber with high stability and wide bandwidth is very important.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a flexible resistive film-metal composite frequency selection surface, and preparation and application thereof.

to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a flexible resistive film-metal composite type frequency selective surface, comprising the steps of:

s1: pasting a photosensitive film with a frequency selection surface pattern printed on the surface on a flexible copper-clad plate, and sequentially carrying out exposure and development to obtain a developed flexible copper-clad plate and expose a copper surface and the frequency selection surface pattern;

S2: etching the developed flexible copper clad laminate to obtain an etched flexible copper clad laminate; the etching is used for removing copper on the copper surface, exposing the surface of the copper-clad plate substrate layer, and simultaneously reserving a photosensitive film attached on the copper-clad plate, wherein the photosensitive film presents a preset frequency selection surface pattern;

s3: performing stripping and drying treatment on the etched flexible copper clad laminate to obtain a stripped flexible copper clad laminate; obtaining a frequency selective surface pattern with a copper surface after demoulding;

s4: adopting a screen printing technology to extrude conductive carbon paste to the surface or the back of the stripped flexible copper-clad plate from meshes of a screen printing plate, and sintering and curing to obtain a resistance film; the screen plate comprises a pre-designed resistive film pattern, and the flexible resistive film with the pre-designed pattern is prepared on the surface or the back surface of the stripped flexible copper-clad plate, so that the flexible resistive film-metal composite type frequency selection surface is obtained.

Preferably, the substrate layer material of the flexible copper clad laminate is glass fiber reinforced epoxy resin or polyimide.

Preferably, the thickness of the flexible copper clad laminate is 0.025 mm-0.8 mm, wherein the thickness of the copper clad laminate on the surface of the copper clad laminate is 0.01 mm-0.02 mm.

Preferably, step S2 is to etch the developed flexible copper clad laminate by weak base solution, wherein the etching temperature is 40-60 ℃; the weak base solution is a sodium carbonate solution, and the concentration of the weak base solution is 30-60 g/L.

Preferably, step S4 is specifically:

S401: placing the surface or the back of the stripped flexible copper clad laminate on a screen printing workbench in a horizontal mode, and exhausting air to fix the flexible copper clad laminate;

S402: placing the screen printing plate above the flexible copper-clad plate in an aligned manner with the flexible copper-clad plate, pouring conductive carbon slurry at one end, applying certain pressure to the carbon slurry part of the screen printing plate by using a scraper, moving towards the other end of the screen printing plate at a constant speed, and extruding the carbon slurry onto the flexible copper-clad plate from meshes of the screen printing plate by using the scraper in the moving process to obtain the flexible copper-clad plate coated with the conductive carbon slurry;

S403: and sintering and curing the flexible copper clad laminate coated with the conductive carbon paste, wherein the cured conductive carbon paste is the resistance film, the screen printing plate comprises a pre-designed resistance film pattern, and thus the flexible resistance film with the pre-designed pattern is prepared on the surface or the back of the stripped flexible copper clad laminate to obtain the flexible resistance film-metal composite frequency selection surface.

Preferably, the conductive carbon paste comprises a carbon material and a resin, the carbon material being one or more of carbon black, graphene and graphite; the resin is epoxy resin or polyamide resin; the conductive carbon paste is used for providing a certain square resistance for the flexible resistive film-metal composite type frequency selection surface, and the square resistance range is 20-1000 omega.

preferably, the sintering and curing temperature is 150-200 ℃ and the time is 30-60 min.

According to another aspect of the invention, the flexible resistive film-metal composite type frequency selective surface prepared by the preparation method is provided.

According to another aspect of the invention, the application of the flexible resistive film-metal composite type frequency selective surface is provided for preparing an electromagnetic wave absorbing device.

According to another aspect of the invention, an electromagnetic wave absorbing device is provided, wherein a functional layer comprises the flexible resistive film-metal composite type frequency selective surface.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

(1) the invention combines photoetching, wet etching and screen printing technologies to prepare the resistive film-metal composite FSS, has simple process operation, and can prepare the large-area flexible FSS applied to curved surfaces. A 600mm by 600mm flexible resistive film-metal composite FSS has been successfully prepared.

(2) The invention adopts the screen printing technology to introduce the resistive film into the preparation process of the FSS wave absorber, thereby eliminating the defect that the metal FSS wave absorber needs to be welded with devices, greatly simplifying the preparation process flow of the FSS wave absorber, shortening the preparation period of the FSS wave absorber and effectively improving the working stability of the FSS wave absorber.

(3) the invention adopts the screen printing technology to introduce the resistive film into the metal FSS wave absorber, and can set the pattern of the screen printing plate according to the requirement, thereby obtaining the required resistive film pattern, the resistive film pattern is matched with the metal FSS pattern, the impedance adjusting range of the wave absorber can be effectively expanded, good impedance matching can be realized in a wider bandwidth range, and broadband wave absorption is realized.

(4) The invention adopts the screen printing technology to introduce the resistive film into the FSS wave absorber, not only can prepare the resistive film with a certain pattern on the surface of the metal FSS, but also can prepare the resistive film with a specific pattern on the back of the metal FSS, and the single-sided and double-sided design can fully embody the application flexibility of the resistive film, improve the compatibility of the resistive film with other technologies and greatly expand the engineering application range of the resistive film.

Drawings

FIG. 1 is a process flow diagram of a method of making an embodiment of the invention;

Fig. 2 is a schematic diagram of a 600mm by 600mm single-sided flexible resistive film-metal composite FSS resistive film pattern according to embodiment 1 of the present invention;

fig. 3 is a schematic diagram of a metal pattern of a 600mm by 600mm single-sided flexible resistive film-metal composite FSS according to embodiment 1 of the present invention;

fig. 4 is a schematic diagram of a 600mm by 600mm double-sided flexible resistive film-metal composite FSS resistive film pattern according to embodiment 2 of the present invention;

Fig. 5 is a schematic diagram of a metal pattern of a 600mm by 600mm double-sided flexible resistive film-metal composite FSS according to embodiment 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The invention provides a preparation method of a flexible resistive film-metal composite type frequency selection surface, as shown in figure 1, comprising the following steps:

S1: pasting a photosensitive film with a frequency selection surface pattern printed on the surface on a flexible copper-clad plate, and sequentially carrying out exposure and development to obtain a developed flexible copper-clad plate and expose a copper surface and the frequency selection surface pattern;

S2: etching the developed flexible copper clad laminate to obtain an etched flexible copper clad laminate; etching to remove copper on the copper surface, exposing the surface of the copper-clad plate, and simultaneously reserving a photosensitive film attached on the copper-clad plate, wherein the photosensitive film presents a preset frequency selection surface pattern;

S3: performing stripping and drying treatment on the etched flexible copper clad laminate to obtain a stripped flexible copper clad laminate; obtaining a frequency selective surface pattern with a copper surface after demoulding;

S4: adopting a screen printing technology to extrude conductive carbon paste to the surface or the back of the stripped flexible copper-clad plate from meshes of a screen printing plate, and sintering and curing to obtain a resistance film; the screen plate comprises a pre-designed resistive film pattern, and the flexible resistive film with the pre-designed pattern is prepared on the surface or the back surface of the stripped flexible copper-clad plate, so that the flexible resistive film-metal composite type frequency selection surface is obtained.

In some embodiments, during the developing step of step S1, the unexposed areas of the photosensitive film are removed by developing to expose the copper surface; the photosensitive film remains in the illuminated area, revealing the frequency selective surface pattern.

in some embodiments, in step S1, a predetermined frequency selective surface pattern is printed on the photosensitive film to obtain a photosensitive film printed with the frequency selective surface pattern; the method specifically comprises the following steps: printing a preset frequency selection surface pattern on a film, wherein the film is transparent and can be sprayed and printed with ink; then, transferring the pattern on the film to a photosensitive film to obtain the photosensitive film printed with the frequency selection surface pattern; the film is preferably a film.

In some embodiments, the photosensitive film in step S1 is a blue photosensitive film or a photosensitive resist.

in some embodiments, the substrate material layer of the flexible copper clad laminate is glass fiber reinforced epoxy resin or polyimide.

in some embodiments, the thickness of the flexible copper clad laminate is 0.025 mm-0.2 mm, and the thickness of the copper clad laminate on the surface of the copper clad laminate is 0.01 mm-0.02 mm.

In some embodiments, step S2 is to etch the developed flexible copper-clad plate with a weak base solution, where the weak base solution is a sodium carbonate solution, and the concentration of the sodium carbonate solution is 30g/L to 60 g/L. Step S2, etching the developed flexible copper clad laminate into chemical etching, wherein the etching temperature is 40-60 ℃.

in some embodiments, step S4 specifically includes:

S401: placing the surface or the back of the stripped flexible copper clad laminate on a screen printing workbench in a horizontal mode, and exhausting air to fix the flexible copper clad laminate;

S402: flatly placing the screen printing plate above the flexible copper-clad plate and aligning the screen printing plate with the flexible copper-clad plate, pouring conductive carbon slurry into one end of the screen printing plate, applying certain pressure to the carbon slurry part of the screen printing plate by using a scraper, moving the screen printing plate towards the other end of the screen printing plate at a constant speed, and extruding the carbon slurry onto the flexible copper-clad plate from meshes of the screen printing plate by using the scraper in the moving process to obtain the flexible copper-clad plate coated with the conductive carbon slurry;

s403: and sintering and curing the flexible copper clad laminate coated with the conductive carbon paste, wherein the cured conductive carbon paste is the resistance film, the screen printing plate comprises a pre-designed resistance film pattern, and thus the flexible resistance film with the pre-designed pattern is prepared on the surface or the back of the stripped flexible copper clad laminate to obtain the flexible resistance film-metal composite frequency selection surface.

The conductive carbon paste adopted by the invention can be obtained commercially and can also be prepared by self. In some embodiments, the conductive carbon paste is a commercially available model number SW-760 conductive carbon paste. The carbon material is one or more of carbon black, graphene and graphite; the resin is epoxy resin or polyamide resin; the conductive carbon paste is used for providing a certain square resistance for the flexible resistive film-metal composite type frequency selection surface, and the square resistance range is 20-1000 omega.

In some embodiments, the sintering and curing temperature is 150-200 ℃ and the time is 30-60 min.

In some embodiments, the thickness of the resistive film in the composite frequency selective surface is 10-30 microns.

The invention also provides the flexible resistive film-metal composite frequency selection surface prepared by the preparation method. The flexible resistive film-metal composite frequency selective surface can be used for preparing an electromagnetic wave absorbing device.

the invention also provides an electromagnetic wave absorbing device, and a functional layer of the electromagnetic wave absorbing device comprises the flexible resistive film-metal composite frequency selective surface.

when the FSS sample cutting device is used, different FSS sample profiles can be cut according to different application parts, and different shapes and specifications can be manufactured according to use requirements so as to meet the requirements of a plane patch and a curved surface patch. The flexible copper clad laminate selected by the invention has the requirements of flexibility and stress.

The following are examples: