CN112886264A

CN112886264A - Electromagnetic scattering film

Info

Publication number: CN112886264A
Application number: CN201911199858.4A
Authority: CN
Inventors: 苏陟; 高强
Original assignee: Guangzhou Fangbang Electronics Co Ltd
Current assignee: Guangzhou Fangbang Electronics Co Ltd
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2021-06-01

Abstract

The invention relates to an electromagnetic scattering film which comprises a conductive layer, wherein a plurality of grooves are formed in the first surface of the conductive layer at intervals, the inner walls of the grooves are spherical, at least one first through hole is formed in the inner wall of each groove, the other end of each first through hole penetrates through the second surface opposite to the first surface, and the maximum value of the distance S between any two points on the outline of the section of each first through hole is smaller than the wavelength lambda of electromagnetic waves incident to the first through hole. The electromagnetic scattering film is provided with the spherical groove on the first surface, and the first through hole communicated with the groove is arranged on the second surface, so that the electromagnetic waves are diffracted and reflected when passing through the electromagnetic scattering film, the propagation direction of the electromagnetic waves is diffused, and the propagation range is expanded.

Description

Electromagnetic scattering film

Technical Field

The invention relates to the technical field of communication, in particular to an electromagnetic scattering film.

Background

In radio communication, since an electromagnetic wave has a physical property of propagating straight, it is necessary to place a receiving device in a propagation direction of the electromagnetic wave, and thus the installation position of the device is limited.

Therefore, there is a need for an electromagnetic scattering film that can change the propagation direction of electromagnetic waves during propagation and expand the propagation range.

Disclosure of Invention

The invention aims to provide an electromagnetic scattering film which can diffract and reflect electromagnetic waves when the electromagnetic waves pass through a first through hole and a groove, so that the propagation direction of the electromagnetic waves is diffused, and the propagation range is expanded.

In order to achieve the purpose, the invention adopts the following technical scheme:

the electromagnetic scattering film comprises a conductive layer, wherein a plurality of grooves are formed in the first surface of the conductive layer at intervals, the inner walls of the grooves are spherical, at least one first through hole is formed in the inner wall of each groove, the other end of each first through hole penetrates through the second surface opposite to the first surface, and the maximum value of the distance S between any two points on the outline of the section of each first through hole is smaller than the wavelength lambda of electromagnetic waves incident to the first through hole.

Further, the first through hole comprises one or more of a combination of a round hole, a square hole, an elliptical hole or a special-shaped hole.

Further, the distance between any two points on the profile of the cross section of the first through hole is smaller than 1/100 of the wavelength λ of the electromagnetic wave.

Further, along at least one direction of the first surface, the distance between two adjacent grooves tends to be large in the middle and small in the two sides.

Further, a grounding layer for grounding is arranged on the second surface of the conductive layer, and the grounding layer is electrically connected with the conductive layer.

Furthermore, a plurality of first through holes are formed in the inner wall of each groove.

Further, along at least one direction of the first surface, the number of the first through holes in each groove is arranged in a trend that the middle part is less, two sides are more.

Further, in each groove, the distance H from the intersection point of the axes of the plurality of first through holes and the inner wall of the groove to the first surface is greater than half of the maximum value of the depth H of the groove.

Further, the groove is filled with a medium.

Further, the electromagnetic scattering film further comprises an insulating layer, and the insulating layer is arranged on the first surface of the conducting layer.

Compared with the prior art, the invention has the beneficial effects that:

according to the electromagnetic scattering film, the spherical groove is formed in the first surface, the first through hole communicated with the groove is formed in the second surface, so that electromagnetic waves are diffracted and reflected when passing through the electromagnetic scattering film, the propagation direction of the electromagnetic waves is diffused, and the propagation range is expanded.

Drawings

Fig. 1 is a sectional view of an electromagnetic scattering film of an embodiment of the present invention.

Fig. 2 is a top view of an electromagnetic scattering film of an embodiment of the present invention.

Fig. 3 is a sectional view of an electromagnetic scattering film according to another embodiment of the present invention.

Fig. 4 is a top view of an electromagnetic scattering film according to another embodiment of the present invention.

Fig. 5 is an enlarged view of a portion of the recess and the first through-hole of fig. 3 according to the present invention.

Fig. 6 is a sectional view of an electromagnetic scattering film according to still another embodiment of the present invention.

In the figure:

1. a conductive layer; 10. a groove; 11. a first through hole; 2. an insulating layer; 3. a ground plane; 31. a second through hole; 4. and (5) a film layer.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings.

As shown in fig. 1, the electromagnetic scattering film provided by the present invention includes a conductive layer 1, a plurality of grooves 10 are disposed on a first surface of the conductive layer 1, inner walls of the grooves 10 are spherical, at least one first through hole 11 is disposed on an inner wall of each groove 10, another end of the first through hole 11 penetrates through a second surface opposite to the first surface, and a maximum value of a distance S between any two points on a profile of a cross section of the first through hole 11 is smaller than a wavelength λ of an electromagnetic wave incident to the first through hole 11. It is understood that the wavelength λ of the electromagnetic wave used for communication is generally between 0.1 mm and 1 m, and the electromagnetic wave has the characteristic of straight propagation, resulting in a relatively narrow signal propagation range. When the electromagnetic wave passes through the small hole with the wavelength lambda smaller than the wavelength lambda, the electromagnetic wave is diffracted and is randomly propagated to the periphery, and the propagation range can be further expanded. In this embodiment, when the electromagnetic wave is incident on the second surface, the electromagnetic wave passes through the first through hole 11 and is diffracted, the electromagnetic wave passing through the first through hole 11 propagates to the periphery, and a part of the electromagnetic wave is incident on the inner wall of the groove 10. The inner wall of the groove 10 is spherical, and the electromagnetic wave is reflected after being incident on the inner wall of the groove 10, so that the propagation direction is further changed, and the electromagnetic wave is propagated to one side of the first surface in disorder. In the embodiment, the spherical groove 10 is arranged on the first surface, and the first through hole 11 communicated with the groove 10 is arranged on the second surface, so that the electromagnetic wave is secondarily diffracted and reflected when passing through the electromagnetic scattering film, and the propagation direction of the electromagnetic wave is diverged and is sequentially propagated, thereby expanding the propagation range.

Note that the distance S between any two points on the contour of the cross section of the first through hole 11 is a straight line distance between any two points on the hole contour line on the radial cross section of the first through hole 11. For example, when the first through hole 11 is a circular hole, the radial cross section is circular, and the distance S between any two points is a straight-line distance between any two points on the circle; when the first through hole 11 is a rectangular hole, the radial cross section is rectangular, and the distance S between any two points is a straight-line distance between any two points on the rectangle.

Specifically, the conductive layer 1 is required to have conductivity and electromagnetic shielding performance. The material of the conductive layer 1 is one or a combination of more of copper, nickel, silver, gold, tin, zinc, lead, chromium and molybdenum, or a conductive rubber material, or other conductive materials. In this embodiment, the conductive layer 1 is a metal layer, preferably a copper foil.

Specifically, the first through hole 11 includes one or a combination of more of a circular hole, a square hole, an elliptical hole, or a special-shaped hole. It can be understood that the first through hole 11 can be flexibly selected according to the difficulty of processing, and only the condition that the electromagnetic wave is diffracted after being incident on the first through hole 11 is satisfied. In the present embodiment, the maximum value of the distance S between any two points on the profile of the cross section of the first through hole 11 is smaller than the wavelength λ of the electromagnetic wave, that is, the size of the first through hole 11 is smaller than the wavelength λ. For example, when the first through hole 11 is a circular hole, the maximum value of the distance S between any two points is the diameter of the first through hole 11; when the first through hole 11 is a rectangular hole, the maximum value of the distance S between any two points is the diagonal distance of the first through hole 11; when the first through hole 11 is a combination of a circular hole and a rectangular hole, the maximum value of the distance S between any two points is the larger of the diameter of the circular hole and the diagonal distance of the rectangular hole. Preferably, the first through hole 11 of the present embodiment is a circular hole.

Specifically, the distance S between any two points on the profile of the cross section of the first through hole 11 is smaller than 1/100 of the wavelength λ of the electromagnetic wave. It is understood that when the distance S between any two points on the cross section of the first through hole 11 is much smaller than the wavelength λ of the electromagnetic wave, the diffraction effect of the electromagnetic wave is more significant. For example: in the present embodiment, the first through hole 11 is a circular hole, the cross section of the circular hole is a circle, the diameter of the circle is the maximum value of the distances S between any two points on the circle, and when the diameter of the circle is smaller than 1/100 of the wavelength λ, the distances S between the other two points are also smaller than 1/100 of the wavelength λ. Therefore, the diameter of the first through hole 11 may be 1/150 or 1/200 of the wavelength λ or other 1/100 size smaller than the wavelength λ. Of course, in other embodiments, a suitable size range of the first through hole 11 may be selected according to an actual use environment.

Specifically, the groove 10 is provided coaxially with the first through hole 11. It is understood that the groove 10 is coaxial with the first through hole 11 such that the central axis of the first through hole 11 is collinear with the central axis of the groove 10. When the electromagnetic wave passes through the first through hole 11 to be diffracted, the electromagnetic wave is transmitted to the periphery by taking the first through hole 11 as the center, and the groove 10 and the first through hole 11 are coaxially arranged, so that more electromagnetic waves can be incident on the spherical surface of the inner wall of the groove 10 and can be reflected.

As shown in fig. 2, the distance between two adjacent grooves 10 in the Y direction of the first surface tends to be larger in the middle and smaller in the two sides. It will be appreciated that the grooves 10 are distributed sparsely at the middle position and more densely at the two side positions on the first surface in the Y direction. The diffraction intensity of the electromagnetic wave is in a trend that the middle part is weak and the two sides are strong, so that more electromagnetic waves can be diffracted at the two sides in the Y direction, and the propagation range of the electromagnetic wave is expanded.

It should be noted that the distance between two adjacent grooves 10 is the straight-line distance between the nearest two points on the contour line of the two adjacent grooves 10 on the first surface.

In another embodiment, the distance between two adjacent grooves 10 along the X direction and the Y direction of the first surface is set in a trend of larger middle part and smaller two sides. In this embodiment, the intensity distribution of the electromagnetic wave is similar to a circle, and the diffraction intensity of the electromagnetic wave is a trend that the middle weak periphery is strong, which is beneficial to causing more electromagnetic waves to diffract at the periphery of the electromagnetic scattering film and expanding the propagation range at the periphery of the electromagnetic scattering film.

As shown in fig. 6, the second surface of the conductive layer 1 is provided with a ground layer 3 for grounding, and the ground layer 3 is electrically connected to the conductive layer 1. In this embodiment, the ground layer 3 is provided to facilitate guiding out the interference charges accumulated in the conductive layer 1 when the electromagnetic scattering film is used, so as to avoid the interference source caused by the accumulation of the interference charges. The ground layer 3 is provided with a second through hole 31 corresponding to the first through hole 11, and the size of the second through hole 31 is not smaller than that of the first through hole 11, so that the electromagnetic wave can enter the first through hole 11 through the second through hole 31. The grounding layer 3 is electrically connected with the conductive layer 1, conductive adhesive can be arranged between the grounding layer 3 and the conductive layer 1, and the grounding layer 3 and the conductive layer 1 are fixedly connected through the conductive adhesive to form an electric path. In other embodiments, the ground layer 3 may be made of conductive material and connected to the conductive layer 1 by soldering. Alternatively, the ground layer 3 and the conductive layer 1 may be integrally formed of the same material.

In another embodiment, the ground layer 3 is formed with a second through hole 31 corresponding to the groove 10, and along the vertical direction of the second surface, the projection of the first through hole 11 is located inside the projection of the second through hole 31, so that the ground layer 3 does not interfere the electromagnetic wave incident to the first through hole 11.

Specifically, the ground layer 3 is required to have conductivity and electromagnetic shielding performance. The material of the ground layer 3 is one or a combination of more of copper, nickel, silver, gold, tin, zinc, lead, chromium, and molybdenum, or a conductive rubber material, or other conductive materials. In the present embodiment, the ground layer 3 is a metal layer, preferably a copper foil.

Specifically, as shown in fig. 3, a plurality of first through holes 11 are opened on the inner wall of each groove 10. It can be understood that the provision of the plurality of first through holes 11 increases the aperture ratio of the conductive layer 1, thereby increasing the diffraction intensity of the electromagnetic wave. Specifically, the opening ratio of the conductive layer 1 is 1% to 99%. It is understood that the opening ratio is a ratio of the sum of areas of cross sections of the plurality of first through holes 11 on the conductive layer 1 to the area of the conductive layer 1. To realize the multi-directional propagation of the electromagnetic wave, it is necessary to ensure that a large amount of the electromagnetic wave passes through the first through hole 11 and is diffracted. If the total area of the first through holes 11 is too large, the remaining amount of the conductive layer 1 is small, easily causing the conductive layer 1 to be broken. If the total area of the first through holes 11 is too small, the diffracted electromagnetic waves are insufficient to achieve multi-azimuth coverage. Therefore, in practical applications, the area ratio of the first through holes 11 can be reasonably designed according to the application scenarios of the circuit board.

In the present embodiment, the plurality of first through holes 11 in each groove 10 includes one or a combination of more of circular holes, square holes, elliptical holes, or irregularly shaped holes. Preferably, the present embodiment uses a circular hole. The size of the plurality of first through holes 11 is smaller than 1/100 of the wavelength of the incident electromagnetic wave. Of course, the plurality of first through holes 11 in each groove 10 may also be set to different sizes, for example, three circular holes are provided in each groove 10, one of which has a diameter of 1/110, the other of which has a diameter of 1/130, and the other of which has a diameter of 1/200. Preferably, the first through holes 11 of the present embodiment have the same size.

In one embodiment, as shown in fig. 4, the number of the first through holes 11 in each groove 10 is set in a trend of a smaller middle part and more sides along the X direction of the first surface. It can be understood that, if the number of the first through holes 11 arranged in the grooves 10 on the two sides of the first surface in the X direction is large, the intensity of the diffraction of the electromagnetic wave in the range is large, which is beneficial to causing more diffraction of the electromagnetic wave on the two sides and expanding the propagation range of the electromagnetic wave.

In another embodiment, the number of the first through holes 11 in each groove 10 is set in a trend of a smaller middle part and more sides along the X direction and the Y direction of the first surface. In this embodiment, the number of the first through holes 11 in each groove 10 is set in a trend of fewer middle parts and more sides along two directions, so that the intensity distribution of the electromagnetic wave diffraction is similar to a circle, the diffraction intensity of the electromagnetic wave in the peripheral region of the first surface is greater than that in the middle region, and the propagation range of the electromagnetic wave is further expanded.

Specifically, as shown in fig. 5, in each groove 10, the distance H from the first surface to the intersection of the axes of the plurality of first through holes 11 and the inner wall of the groove 10 is greater than one-half of the maximum value of the depth H of the groove 10. It is understood that the depth H of the groove 10 is a vertical distance from any point on the inner wall of the groove 10 to the opening end face of the groove 10, and since the groove 10 is spherical, the maximum value of the depth H of the groove 10 is a vertical distance from the intersection point of the central axis of the groove 10 and the inner wall to the opening end face of the groove 10. The distance h from the intersection point of the axis of the first through hole 11 and the inner wall of the groove 10 to the first surface is the depth h of the first through hole 11 along the opening end face of the inner wall of the groove 10. The depth H of the opening end surface of the first through hole 11 is greater than one half of the maximum depth H of the groove 10, and it can also be understood that the first through hole 11 is located in the lower half area of the inner wall of the groove 10 along the opening end surface of the groove 10, i.e. the bottom area of the groove 10. In this embodiment, the plurality of first through holes 11 are disposed in the bottom region of the groove 10, so that the diffracted electromagnetic waves can be reflected in the top region of the groove 10. The first through hole 11 is disposed at a position lower than half of the maximum depth H of the groove 10, which is beneficial to providing a sufficient reflection surface for electromagnetic waves.

Specifically, the groove 10 is filled with a medium. It will be appreciated that the grooves 10 are filled with a medium, and that the propagation direction of the electromagnetic wave can be further changed by the electromagnetic wave being refracted when passing through the medium after being reflected along the spherical surface of the grooves 10. Meanwhile, the grooves 10 are filled with media, so that the strength of the conductive layer 1 is improved, and the conductive layer 1 is prevented from deforming when being extruded by external force. In this embodiment, the electromagnetic wave is incident on the second surface of the conductive layer 1, passes through the first through hole 11, and is diffracted, and the electromagnetic wave is divergently propagated from one end of the first through hole 11 away from the second surface to the surroundings. A part of the electromagnetic wave propagates to the first surface side of the conductive layer 1 along the open end of the groove 10, and another part of the electromagnetic wave is incident on the inner wall of the groove 10. Since the inner wall of the recess 10 is a spherical surface, the reflection normal at each point on the surface of the inner wall has a different mean square direction, and thus the electromagnetic waves incident on the spherical inner wall have different directions after reflection and propagate disorderly to the first surface side of the conductive layer 1. Meanwhile, the electromagnetic wave diffracted by the first through hole 11 and reflected by the inner wall of the groove 10 passes through the medium filled in the groove 10 and is refracted, and the propagation direction of the electromagnetic wave can be further changed by deflection.

In another embodiment, the refractive index of the medium in the recess 10 is arranged with a tendency to be smaller in the middle and larger on both sides in at least one direction of the first surface. It is understood that the greater the refractive index of the medium, the greater the deflection that occurs when an electromagnetic wave passes through the medium. In this embodiment, the refractive indexes of the media at the two sides are large, so that the electromagnetic waves at the two sides are greatly deflected when passing through the media, which is beneficial to scattering the electromagnetic waves toward the peripheral direction of the electromagnetic scattering film, thereby further expanding the propagation range.

Specifically, the electromagnetic scattering film further includes an insulating layer 2, and the insulating layer 2 is provided on the first surface of the conductive layer 1. An insulating layer 2 is provided on the first surface, on the one hand to protect the conductive layer 1 and on the other hand for connection to other components.

Specifically, the insulating layer 2 is provided with concave portions or convex portions distributed in a net shape on the side away from the conductive layer 1. The concave or convex part can increase the bonding area of the surface, and is beneficial to connecting the surface with other components.

Specifically, the insulating layer 2 and the conductive layer 1 are connected by adhesion.

Specifically, referring to fig. 6, the second surface of the conductive layer 1 is further provided with a glue film layer 4, the ground layer 3 is embedded in the glue film layer 4, and a surface of the ground layer 3 on a side away from the conductive layer 1 is flush with a surface of the glue film layer 4 on a side away from the conductive layer 1. The adhesive film layer 4 is used for connection with other components.

The remarkable effects of the embodiment are as follows: the electromagnetic scattering film is provided with the spherical groove 10 on the first surface and the first through hole 11 communicated with the groove 10 on the second surface, so that the electromagnetic waves are diffracted and reflected when passing through the electromagnetic scattering film, the propagation direction of the electromagnetic waves is diffused, and the propagation range is expanded.

The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.

Claims

1. The electromagnetic scattering film is characterized by comprising a conductive layer (1), wherein a plurality of grooves (10) are formed in the first surface of the conductive layer (1) at intervals, the inner walls of the grooves (10) are spherical, at least one first through hole (11) is formed in the inner wall of each groove (10), the other end of each first through hole (11) penetrates through the second surface opposite to the first surface, and the maximum value of the distance S between any two points on the outline of the cross section of each first through hole (11) is smaller than the wavelength lambda of electromagnetic waves incident to the first through hole (11).

2. The electromagnetic scattering film of claim 1, wherein the first through holes (11) comprise one or a combination of round holes, square holes, elliptical holes, or profiled holes.

3. The electromagnetic scattering film according to claim 1, wherein the distance S between any two points on the profile of the cross section of the first through-hole (11) is smaller than 1/100 of the wavelength λ of the electromagnetic wave.

4. The electromagnetic scattering film according to claim 1, wherein the distance between two adjacent grooves (10) is set in a trend of larger middle part and smaller sides along at least one direction of the first surface.

5. The electromagnetic scattering film of claim 1, wherein the second surface of the conductive layer (1) is provided with a ground layer (3) for grounding, and the ground layer (3) is electrically connected to the conductive layer (1).

6. The electromagnetic scattering film of claim 1, wherein the inner wall of each groove (10) is provided with a plurality of first through holes (11).

7. The electromagnetic scattering film of claim 6, wherein the number of first through holes (11) in each groove (10) is set in a tendency of a smaller middle part and more sides in at least one direction of the first surface.

8. The electromagnetic scattering film according to claim 6, wherein in each groove (10), the distance H from the intersection point of the axis of the first through-hole (11) and the inner wall of the groove (10) to the first surface is greater than half of the maximum value of the depth H of the groove (10).

9. The electromagnetic scattering film of claim 1, wherein the grooves (10) are filled with a medium.

10. The electromagnetic scattering film of claim 1, further comprising an insulating layer (2), wherein the insulating layer (2) is disposed on the first surface of the conductive layer (1).