Ultra-wideband radar cross section reduction structure and apparatus

Abstract

The application discloses a radar cross section reduction structure and equipment of ultra-wideband, comprising a metal floor, a metal surface layer formed on the metal floor; wherein the metal surface layer comprises a plurality of sub-surfaces arranged in the direction away from the metal floor, each layer of the sub-surfaces is composed of a plurality of metal sheets and a plurality of gaps arranged alternately, the number of the metal sheets in the sub-surfaces increases layer by layer in the preset increasing mode along the direction away from the metal floor, and the area of each metal sheet in the sub-surfaces decreases layer by layer in the preset area decreasing mode along the direction away from the metal floor; the distance between each metal sheet in each layer of the sub-surfaces and the metal sheet of the next layer or the metal floor is the same, and the height of each metal sheet in each layer of the sub-surfaces and the metal sheet of the next layer or the metal floor decreases layer by layer in the preset height decreasing mode along the direction away from the metal floor. The structure is not sensitive to the polarization direction and has good work frequency band portability.

Description

Technical Field

[0001] This invention relates to the field of radar cross section reduction technology, and in particular to an ultra-wideband radar cross section reduction structure and device. Background Technology

[0002] Since the advent of radar detection technology, radar cross-section (RCS) reduction technology has also developed. With the increase in the operating bandwidth of radar antennas, broadband RCS reduction technology has become increasingly important.

[0003] Currently, there are many methods for achieving broadband RCS reduction, such as methods based on absorbing materials, methods based on shape technology, and methods based on electromagnetic metasurface technology. Methods based on absorbing materials have advantages such as wide operating bandwidth and good reduction effect, but they are bulky, have low strength, and are difficult to conform to airborne equipment, so they are often used to build microwave anechoic chambers, limiting their application in the defense field. Methods based on shape technology mainly achieve RCS reduction by controlling the direction and path of the induced current, mainly including slotting and using various special structures represented by biomimetic and fractal methods. The main drawback of this method is its narrow operating bandwidth and small reduction magnitude. The main methods for achieving broadband RCS reduction based on electromagnetic metasurface technology can be divided into three categories: converting the polarization direction of the incident wave through polarization conversion metasurfaces; absorbing the energy of the incident wave through absorbers; and achieving phase destructive through checkerboard metasurfaces.

[0004] Methods based on electromagnetic metasurface technology offer a wide operating bandwidth and are easy to integrate with other devices, thus attracting widespread attention. However, compared to demanding requirements, the operating bandwidth of the currently achieved RCS reduction still needs further improvement to reduce the probability of radar detection of targets using RCS reduction structures. Summary of the Invention

[0005] To address the aforementioned technical problems, embodiments of the present invention provide an ultra-wideband radar cross section reduction structure and device to solve the technical problem of insufficient bandwidth in existing radar cross section reduction technologies.

[0006] This invention provides an ultra-wideband radar cross-section reduction structure, the structure comprising:

[0007] Metal flooring;

[0008] A metal surface layer formed on a metal floor;

[0009] The metal surface layer includes several sub-surfaces stacked sequentially away from the metal floor. Each sub-surface is composed of several metal sheets and several gaps arranged alternately. Along the direction away from the metal floor, the number of metal sheets in the sub-surface increases layer by layer according to a preset increasing method. Along the direction away from the metal floor, the area of ​​each metal sheet in the sub-surface decreases layer by layer according to a preset area decreasing method.

[0010] Each metal sheet on each sub-surface is equidistant from the metal sheet or metal floor of the next layer. Along the direction away from the metal floor, the height of each metal sheet on each sub-surface from the metal sheet or metal floor of the next layer decreases layer by layer according to a preset height reduction method.

[0011] In one possible implementation of the first aspect, a dielectric layer is also included, which is disposed between the metal sheet on each sub-surface and the metal sheet or metal ground of the next layer.

[0012] The medium layer is composed of several medium boards stacked sequentially facing away from the metal floor, or it is composed of foam boards.

[0013] One possible implementation of the first aspect also includes:

[0014] If the surface of the substrate is connected to the metal sheet, it is not covered with metal; if the surface of the substrate is not connected to the metal sheet, it is covered with a layer of metal.

[0015] If the bottom surface of the dielectric substrate is connected to the surface of the dielectric substrate of the next layer, no metal is used. If the bottom surface of the dielectric substrate is connected to the surface of the metal floor, a layer of metal is used as the metal floor.

[0016] One possible implementation of the first aspect also includes:

[0017] The metal sheets and gaps in each sub-surface are squares of equal area, and the number of metal sheets and gaps in each sub-surface is equal.

[0018] In one possible implementation of the first aspect, the preset method of increasing the number of metal sheets in each sub-surface is to calculate the number of sub-surface layers, wherein the formula for calculating the number of metal sheets in the sub-surface is:

[0019] n=2 (2p-1)

[0020] In the formula, n is the number of metal sheets in the p-th sub-surface, and p is the number of layers in which the sub-surface is located.

[0021] In one possible implementation of the first aspect, the preset area reduction method is that the area of ​​each metal sheet in the sub-surface is calculated based on the side length of the metal sheet, wherein the side length of each metal sheet in the sub-surface is:

[0022]

[0023] In the formula, L is the side length of the metal floor, and p is the number of layers in which the metal sheet is located.

[0024] In one possible implementation of the first aspect, the preset height reduction method is that, along the direction away from the metal floor, the height of each metal sheet in each sub-surface and the metal sheet of the previous layer is half the height of the sub-surface and the metal sheet of the next layer or the metal floor.

[0025] In one possible implementation of the first aspect, the height of each metal sheet in the first sub-surface from the metal floor is 25 mm.

[0026] In one possible implementation of the first aspect, the metal floor, the metal sheet, and the metal are made of copper.

[0027] In one possible implementation of the first aspect, the dielectric constant of the foam board is 1.05.

[0028] This invention provides a device for applying an ultra-wideband radar cross-section reduction structure as provided in this invention.

[0029] The technical solution of this invention has the following advantages:

[0030] The ultra-wideband radar cross section reduction structure provided in this invention includes a metal floor and a metal surface layer formed on the metal floor. The metal surface layer comprises several sub-surfaces stacked sequentially away from the metal floor. Each sub-surface consists of several metal sheets and several gaps arranged alternately. Along the direction away from the metal floor, the number of metal sheets in the sub-surface increases layer by layer according to a preset increasing method, and the area of ​​each metal sheet in the sub-surface decreases layer by layer according to a preset decreasing method. The distance between each metal sheet in each sub-surface and the metal sheet or metal floor in the next layer is the same. Along the direction away from the metal floor, the height between each metal sheet in each sub-surface and the metal sheet or metal floor in the next layer decreases layer by layer according to a preset decreasing method. This structure solves the problem of insufficient bandwidth in existing radar cross section reduction technologies and is insensitive to polarization direction, exhibiting good portability in the operating frequency band. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a structural diagram of the ultra-wideband radar cross-section reduction structure in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the dielectric substrate structure of the ultra-wideband radar cross section reduction structure in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the copper-clad substrate layers of the ultra-wideband radar cross section reduction structure in an embodiment of the present invention;

[0035] Figure 4 This is a diagram of the first sub-surface structure of the ultra-wideband radar cross section reduction structure in an embodiment of the present invention;

[0036] Figure 5 This is a diagram of the second sub-surface structure of the ultra-wideband radar cross section reduction structure in an embodiment of the present invention;

[0037] Figure 6 This is a structural diagram of a two-layer sub-surface stacked structure for an ultra-wideband radar cross-section reduction structure in an embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram of the RCS value of the ultra-wideband radar cross section reduction structure in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram illustrating the RCS reduction effect of the ultra-wideband radar cross section reduction structure in an embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The ultra-wideband radar cross-section reduction structure provided in the embodiments of the present invention, such as... Figure 1 As shown, Figure 1 The diagram shows a reduced radar cross section structure for ultra-wideband radar, including:

[0042] Metal flooring;

[0043] A metal surface layer formed on a metal floor;

[0044] The metal surface layer includes several sub-surfaces stacked sequentially away from the metal floor. Each sub-surface is composed of several metal sheets and several gaps arranged alternately. Along the direction away from the metal floor, the number of metal sheets in the sub-surface increases layer by layer according to a preset increasing method. Along the direction away from the metal floor, the area of ​​each metal sheet in the sub-surface decreases layer by layer according to a preset area decreasing method.

[0045] Each metal sheet on each sub-surface is equidistant from the metal sheet or metal floor of the next layer. Along the direction away from the metal floor, the height of each metal sheet on each sub-surface from the metal sheet or metal floor of the next layer decreases layer by layer according to a preset height reduction method.

[0046] In this embodiment, the ultra-wideband radar cross section reduction structure includes a metal floor and a metal surface layer formed by stacking m sub-surfaces on the metal floor, wherein the sub-surfaces of each layer in this special metal surface layer are formed by alternating metal sheets and voids.

[0047] Using the metal floor surface as a plane, sub-surfaces are stacked vertically upwards from the metal floor surface. The number of metal sheets in the sub-surface increases layer by layer, while the area of ​​each metal sheet in the sub-surface decreases layer by layer. The height of each metal sheet in each layer of the sub-surface relative to the metal sheet or metal floor of the next layer decreases layer by layer according to a preset height reduction method.

[0048] The final radar cross section reduction structure is composed of Composed of a metal sheet and a metal floor, the final radar cross section reduction structure can achieve RCS reduction effect within the structure.

[0049] In one embodiment, a dielectric layer is disposed between a metal sheet on each sub-surface and a metal sheet or metal floor of the next layer.

[0050] The medium layer is composed of several medium boards stacked sequentially facing away from the metal floor, or it is composed of foam boards.

[0051] In this embodiment, during stacking, a dielectric layer is used instead of an air plate to support each metal floor layer and the next metal floor layer, or to support each metal floor layer and the previous metal floor layer. This dielectric layer is formed by stacking multiple copper-coated dielectric substrates.

[0052] The dielectric layer can also be made of foam board with a dielectric constant of 1.05. This makes the dielectric layer very similar to air, which makes the propagation of radar waves in the dielectric board more uniform and avoids the spread of radar wave energy in unexpected directions due to scattering. This helps to control the scattering of radar waves in a specific low-threat direction and improve the stealth effect.

[0053] In one embodiment, if the surface of the dielectric substrate is connected to the metal sheet, it is not covered with metal; if the surface of the dielectric substrate is not connected to the metal sheet, it is covered with a layer of metal.

[0054] If the bottom surface of the dielectric substrate is connected to the surface of the dielectric substrate of the next layer, no metal is used. If the bottom surface of the dielectric substrate is connected to the surface of the metal floor, a layer of metal is used as the metal floor.

[0055] In this embodiment, if the bottom dielectric substrate in the radar cross-section reduction structure has a copper backing as a ground plane and a copper top layer as a sub-surface, while the other dielectric substrates only have a copper top layer as a sub-surface and no copper backing, the dielectric substrate structure diagram is as follows. Figure 2 As shown. Specifically, if the surface of the dielectric substrate is to be connected to the metal sheet, then no metal is covered, and the metal sheet is used as the surface of the dielectric substrate. If the surface of the dielectric substrate is not connected to the metal sheet, then a layer of metal is covered, and then it is connected to the bottom surface of the dielectric substrate above.

[0056] If the bottom surface of the dielectric substrate is connected to the surface of the next dielectric substrate, no metal cover is required. If the bottom surface of the dielectric substrate is to be connected to the surface of the metal floor, a metal cover is applied, and the substrate directly becomes the metal floor. Figure 3 As shown.

[0057] In one embodiment, the metal sheets and gaps in each sub-surface are squares of equal area, and the number of metal sheets and gaps in each sub-surface is equal.

[0058] In this embodiment, the metal sheets and gaps on each sub-surface are square, with equal areas, and the number of metal sheets and gaps is also equal, such as... Figure 4 As shown, the first sub-surface consists of 2 (2p-1) = 2 sides with length It consists of a square metal sheet PEC1 and two square gaps of equal area arranged alternately.

[0059] In one embodiment, the preset addition method is that the number of metal sheets in each sub-surface is calculated based on the number of sub-surface layers, wherein the formula for calculating the number of metal sheets in the sub-surface is:

[0060] n=2 (2p-1)

[0061] In the formula, n is the number of metal sheets in the p-th sub-surface, and p is the number of layers in which the sub-surface is located.

[0062] In this embodiment, the number of metal sheets in the sub-surface of the p-th layer is 2. (2p-1) One, such as Figure 4 As shown, the first sub-surface consists of 2 (2p-1) = It consists of two square metal sheets PEC1 and two square gaps of equal area arranged alternately;

[0063] like Figure 5 As shown, the second sub-surface consists of 2 (2p-1) = It consists of 8 square metal sheets PEC2 and 8 gaps of equal area to the metal sheets arranged alternately;

[0064] like Figure 6 As shown, the two sub-surface layers are stacked on a square metal floor GND with a side length of L = 200 mm. Note that S 金属地板面积 =S 金属片面积 +S 空隙面积 =2S 金属片面积 The final RCS values ​​for the equal-area metal floor and the radar cross section reduction structure are as follows: Figure 7 The dashed and solid lines are shown, and the RCS reduction effect of the radar cross section reduction structure is obtained as follows: Figure 8 As shown. By Figure 8 It can be seen that the radar cross section reduction structure can achieve the RCS reduction effect within the structure.

[0065] In one embodiment, the preset area reduction method is that the area of ​​each metal sheet in the sub-surface is calculated based on the side length of the metal sheet, wherein the side length of each metal sheet in the sub-surface is:

[0066]

[0067] In the formula, L is the side length of the metal floor, and p is the number of layers in which the metal sheet is located.

[0068] In this embodiment, the area of ​​each metal sheet in the sub-surface is calculated based on the side length of the metal sheet, wherein the side length of each metal sheet in the sub-surface is:

[0069]

[0070] In the formula, L is the side length of the metal floor, and p is the number of layers in which the metal sheet is located.

[0071] As an example of this embodiment, the first sub-surface consists of two sides with a length of... It consists of a square metal sheet PEC1 and two square gaps of equal area arranged alternately.

[0072] like Figure 5As shown, the second sub-surface consists of 8 edges with a length of... It consists of a square metal sheet PEC2 and eight gaps of equal area arranged alternately.

[0073] like Figure 6 As shown, the two sub-surface layers are stacked on a square metal floor GND with a side length of L = 200 mm. Note that S 金属地板面积 =S 金属片面积 +S 空隙面积 =2S 金属片面积 .

[0074] In one embodiment, the preset height reduction method is that, along the direction away from the metal floor, the height of each metal sheet in each sub-surface and the metal sheet of the previous layer is half the height of the sub-surface and the metal sheet of the next layer or the metal floor.

[0075] In this embodiment, the preset height reduction method is that, along the direction away from the metal floor, the height of each metal sheet in each sub-surface and the metal sheet of the previous layer is half the height of the sub-surface and the metal sheet of the next layer or the metal floor.

[0076] In one embodiment, the height of each metal sheet on the first sub-surface from the metal floor is 25 mm.

[0077] In this embodiment, the stacking rule is to ensure that the distance between all metal sheets PEC1 constituting the first sub-surface and the nearest metal sheet (i.e., the metal ground plane) below them is always h1 = 25 mm; the distance between all metal sheets PEC2 constituting the second sub-surface and the nearest metal sheet below them (some metal sheets are below the metal ground plane, and some metal sheets are below the metal sheet PEC1) is always h2 = 12.5 mm.

[0078] In one embodiment, the metal floor, the metal sheet, and the metal are made of copper.

[0079] In this embodiment,

[0080] In one embodiment, the dielectric constant of the foam board is 1.05.

[0081] In this embodiment, a foam board with a dielectric constant of 1.05 is used, which is very close to air.

[0082] This invention provides a device for applying an ultra-wideband radar cross-section reduction structure as provided in this invention.

[0083] ​The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A structure for reducing the radar cross section of an ultra-wideband radar, characterized in that, include: Metal flooring; A metal surface layer formed on the metal floor; The metal surface layer includes several sub-surfaces stacked sequentially away from the metal floor. Each sub-surface is composed of several metal sheets and several gaps arranged alternately. Along the direction away from the metal floor, the number of metal sheets in the sub-surface increases layer by layer according to a preset increasing method. Along the direction away from the metal floor, the area of ​​each metal sheet in the sub-surface decreases layer by layer according to a preset area decreasing method. In each of the sub-surface layers, the distance between each metal sheet and the metal sheet or metal floor of the next layer is the same. Along the direction away from the metal floor, the height between each metal sheet and the metal sheet or metal floor of the next layer decreases layer by layer according to a preset height reduction method.

2. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, It also includes a dielectric layer disposed between the metal sheet on each of the sub-surfaces and the metal sheet or metal floor of the next layer; The dielectric layer is composed of a stack of dielectric plates arranged sequentially away from the direction of the metal floor, or it is composed of foam boards with a dielectric constant of 1.

05.

3. The ultra-wideband radar cross-section reduction structure as described in claim 2, characterized in that, Also includes: If the surface of the dielectric substrate is connected to the metal sheet, it is not covered with metal; if the surface of the dielectric substrate is not connected to the metal sheet, it is covered with a layer of metal. If the bottom surface of the dielectric plate is connected to the surface of the dielectric plate of the next layer, no metal is applied. If the bottom surface of the dielectric plate is connected to the surface of the metal floor, a layer of metal is applied to serve as the metal floor.

4. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, It also includes: the metal sheets and the gaps in each of the sub-surface layers are squares of equal area, and the number of metal sheets and the gaps in each of the sub-surface layers is equal.

5. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, The preset addition method involves calculating the number of metal sheets in each sub-surface layer based on the number of sub-surface layers. The formula for calculating the number of metal sheets in each sub-surface layer is as follows: n＝2 (2p-1) In the formula, n is the number of metal sheets in the p-th layer of the sub-surface, and p is the layer number in which the sub-surface is located.

6. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, The preset area reduction method involves calculating the area of ​​each metal sheet in the sub-surface based on the side length of the metal sheet, wherein the side length of each metal sheet in the sub-surface is: In the formula, L is the side length of the metal floor, and p is the number of layers in which the metal sheet is located.

7. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, The preset height reduction method is that, along the direction away from the metal floor, the height of each metal sheet in each sub-surface and the metal sheet of the previous layer is half the height of the sub-surface and the metal sheet of the next layer or the metal floor.

8. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, The height of each metal sheet in the first layer of the sub-surface relative to the metal floor is 25 mm.

9. The ultra-wideband radar cross-section reduction structure as described in claim 1, characterized in that, The metal floor, the metal sheet, and the metal are made of copper.

10. A device, characterized in that, The device is used to apply an ultra-wideband radar cross-section reduction structure as described in any one of claims 1-9.

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