An ATA-type integrated absorber-permeable structural unit and material with high angular stability

Abstract

An ATA-type integrated absorber-transmitter structure unit with high angular stability includes a first impedance layer, a second impedance layer, and a frequency selective surface layer arranged from top to bottom. The first impedance layer consists of four identical cubic structures with openings at the top and bottom, forming a grid pattern. The sides of each cubic structure are first dielectric layers, and first metal layers are attached to the outer surfaces of two adjacent sides of the same cubic structure. The second impedance layer includes a rectangular second dielectric layer and a square annular second metal layer located on the upper surface of the second dielectric layer. The frequency selective surface layer includes a third dielectric layer and a fourth metal layer located on the upper surface of the third dielectric layer. The fourth metal layer has metal slits with the exact same shape and position as the X-shaped slits. The ATA-type integrated absorber-transmitter material of this invention has symmetrical characteristics, giving the overall material dual-polarization properties and a balanced absorption and transmission effect.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to artificial electromagnetic materials technology, and more specifically to an ATA-type integrated absorber-permeable structural unit and material with high angular stability. Background Technology

[0002] In modern strategic development, with the advancement of stealth technology, radar antenna systems and various radio frequency sensors on stealth aircraft platforms have become major contributors to radar cross-section, making their stealth design crucial to the overall stealth performance of the aircraft. However, as the front end of information exchange, radar antennas must ensure their normal transmission and reception of electromagnetic waves; therefore, stealth design cannot be achieved directly through methods such as shape stealth design or applying radar-absorbing materials.

[0003] Penetration-absorbing integrated materials are a novel type of artificial electromagnetic material. They combine a frequency-selective surface and a circuit-simulated absorber in a composite structure. This allows for the normal transmission and penetration of signals within the operating frequency band, while also absorbing rather than reflecting out-of-band electromagnetic waves, thus comprehensively reducing electromagnetic scattering. Since electromagnetic waves emitted by radar systems often strike aircraft at an oblique angle, penetration-absorbing integrated materials must possess excellent angular stability when operating in the absorbing frequency band. Currently, the angular stability of existing penetration-absorbing integrated materials is generally around 30°, with a few reaching 45°. However, ensuring high angular stability often results in a very narrow absorption bandwidth. Therefore, to achieve better stealth performance, penetration-absorbing integrated materials urgently need to possess higher angular stability within a given absorption bandwidth. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention discloses an ATA-type integrated absorber-permeable structural unit and material with high angular stability.

[0005] The present invention provides an ATA-type integrated absorber structure unit with high angular stability, characterized in that it comprises a first impedance layer, a second impedance layer, and a frequency selective surface layer arranged from top to bottom.

[0006] The first impedance layer is composed of four identical cubic structures with openings at the top and bottom, forming a grid shape. The sides of the cubes are first dielectric layers, and the outer surfaces of two adjacent sides of the same cube are covered with first metal layers.

[0007] The first metal layer includes an array of horizontal metal strips that are progressively longer from top to bottom and are arranged in parallel and equally spaced arrays in an isosceles trapezoidal shape, and a vertical metal strip that vertically connects the midpoints of all the horizontal metal strips.

[0008] The second impedance layer includes a rectangular second dielectric layer, a square annular second metal layer located on the upper surface of the second dielectric layer, and a third metal layer located on the upper surface of the second dielectric layer and surrounded by the second metal layer; the second metal layer has an equal number of identical resistors evenly distributed on each side; the third metal layer has an X-shaped slit in the middle composed of four sub-slits, the sub-slits being formed by multiple right-angled zigzag slits and end slits connected together, the right-angled zigzag slits being perpendicular to each other, the outer ends of the sub-slits being perpendicularly connected to the end slits with a width greater than the width of the right-angled zigzag slits, and the inner ends of the four sub-slits being connected together in a cross shape;

[0009] The frequency selective surface layer includes a third dielectric layer and a fourth metal layer located on the upper surface of the third dielectric layer; the fourth metal layer has metal slots with the same shape and position as the X-shaped slots;

[0010] The first impedance layer and the second impedance layer are connected, and the space between the second impedance layer and the frequency selection surface layer is a gas medium.

[0011] Preferably, the first impedance layer, the second impedance layer, and the frequency selective surface layer have the same planar projection size.

[0012] Preferably, the first dielectric layer is an epoxy fiberglass board, and the second and third dielectric layers are made of Rogers RO4350B.

[0013] Preferably, the first dielectric layer, the second dielectric layer, and the third dielectric layer are all 24mm × 24mm squares; wherein the height of the first dielectric layer is 14mm, and the distance between the second dielectric layer and the third dielectric layer is 8mm.

[0014] Preferably, the length of the top horizontal metal strip in the first metal layer is 3.2 mm, each lower horizontal metal strip is 0.4 mm larger than the upper metal strip, the length of the vertical metal strip is 7.8 mm, the width of each metal strip is 0.2 mm, and the distance from the bottom horizontal metal strip to the second impedance layer is 3.2 mm.

[0015] Preferably, the thickness of the second dielectric layer and the third dielectric layer is 0.254 mm, the side length of the annular square formed by the second metal layer is 20 mm and the width is 1 mm, the gap width of the resistors located inside the second metal layer is 0.5 mm, and the spacing between each resistor is 1.6 mm; the sub-gap is formed by connecting nine right-angled zigzag gaps with a length of 0.9 mm and a width of 0.4 mm end to end, and the end gap has a length of 3 mm and a width of 0.8 mm.

[0016] This invention also discloses an ATA-type absorber-permeable integrated material with high angular stability, comprising N 2 There are 16 structural units arranged in a square shape, where N is an integer greater than 1.

[0017] The ATA-type absorbent-permeable integrated material with high angular stability described in this invention has the following technical advantages and performance characteristics:

[0018] The ATA-type integrated absorber-transmitter material of this invention has symmetrical features, which gives the overall material dual polarization characteristics and balanced wave absorption and wave transmission effects.

[0019] The ATA-type absorbent-permeable integrated material of this invention is composed of a combination of three-dimensional and two-dimensional structures, both of which can be realized by printed PCB boards, resulting in low cost and simple processing.

[0020] The ATA-type integrated absorber-transmitter material of this invention, in TE mode, absorbs waves in the range of 2.21-3.59GHz and 8.43-11.62GHz with a relative bandwidth of 47.59%+31.82%=79.41% when the incident angle is 0°, and transmits waves at 5.65GHz with an insertion loss of 0.88dB.

[0021] When the incident angle is 60°, the absorption bandwidth in the 2.23-3.59GHz and 8.43-10.46GHz range is 46.73%+21.49%=68.22%.

[0022] In TM mode, at an incident angle of 0°, it absorbs waves in the 2.21-3.59GHz and 8.43-11.62GHz ranges with a relative bandwidth of 47.59%+31.82%=79.41%, transmits waves at 5.65GHz, and has an insertion loss of 0.88dB. When the incident angle is 30°, it absorbs waves in the 2.4-3.59GHz and 8.43-11.2GHz ranges with a relative bandwidth of 39.73%+28.22%=67.95%.

[0023] The ATA-type integrated absorber material of this invention has a minimum operating frequency of 2.21 GHz and a maximum operating wavelength of 135.75 mm. The size of the unit is only 0.17 times the wavelength, which has the characteristics of miniaturization. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a specific embodiment of the integrated absorbent-permeable structural unit of the present invention;

[0025] Figure 2 This is a schematic diagram of a specific embodiment of the first impedance layer of the present invention;

[0026] Figure 3 This is a schematic diagram of a specific embodiment of the second impedance layer of the present invention;

[0027] Figure 4 This is a schematic diagram of a specific embodiment of the frequency selective surface layer described in this invention;

[0028] Figure 5 This is a graph showing the S-parameters S11 and S21 of the integrated absorbent and breathable material of the present invention under vertical incidence in a specific embodiment.

[0029] Figure 6 The S11 parameter curves of the integrated absorbent and permeable material of the present invention under two polarizations under incident waves at different angles in a specific embodiment of the material.

[0030] Figure 7 The diagram shows the absorption effect of the integrated absorber-permeable material of the present invention under two polarizations under incident waves at different angles in a specific embodiment.

[0031] Figures 5 to 7 In the diagram, section a on the left shows the TE polarization results curves; section b on the right shows the TM polarization results curves; the horizontal axis represents frequency, in GHz. Figure 5 The vertical axis represents the S-parameters, i.e., the scattering parameters. Figure 6 The ordinate of the middle axis represents the S11 parameter. Figure 7 The vertical axis represents the absorption rate.

[0032] The figures are labeled as follows: 1-First impedance layer, 2-First dielectric layer, 3-First metal layer, 4-Second impedance layer, 5-Second metal layer, 6-Resistor, 7-Third metal layer, 8-Second dielectric layer, 9-Frequency selective surface layer, 10-Fourth metal layer. Detailed Implementation

[0033] The specific embodiments of the present invention will be described in further detail below.

[0034] This invention discloses an ATA-type integrated absorber structure unit with high angular stability, comprising a first impedance layer, a second impedance layer, and a frequency selective surface layer arranged from top to bottom;

[0035] The first impedance layer is composed of four identical cubic structures with openings at the top and bottom, forming a grid shape. The sides of the cubes are first dielectric layers, and the outer surfaces of two adjacent sides of the same cube are covered with first metal layers.

[0036] The first metal layer includes an array of horizontal metal strips that are progressively longer from top to bottom and are arranged in parallel and equally spaced arrays in an isosceles trapezoidal shape, and a vertical metal strip that vertically connects the midpoints of all the horizontal metal strips.

[0037] The second impedance layer includes a rectangular second dielectric layer, a square annular second metal layer located on the upper surface of the second dielectric layer, and a third metal layer located on the upper surface of the second dielectric layer and surrounded by the second metal layer; the second metal layer has an equal number of identical resistors evenly distributed on each side; the third metal layer has an X-shaped slit in the middle composed of four sub-slits, the sub-slits being formed by multiple right-angled zigzag slits and end slits connected together, the right-angled zigzag slits being perpendicular to each other, the outer ends of the sub-slits being perpendicularly connected to the end slits with a width greater than the width of the right-angled zigzag slits, and the inner ends of the four sub-slits being connected together in a cross shape;

[0038] The frequency selective surface layer includes a third dielectric layer and a fourth metal layer located on the upper surface of the third dielectric layer; the fourth metal layer has metal slots with the same shape and position as the X-shaped slots;

[0039] The first impedance layer and the second impedance layer are connected, and the space between the second impedance layer and the frequency selection surface layer is a gaseous medium, such as air.

[0040] In this invention, the cubic unit shape with openings at the top and bottom in the first impedance layer is used to fix the first metal layer. The first metal layer attached to the outer surfaces of two adjacent sides can absorb electromagnetic waves in the high-frequency band. Since metal strips of different lengths affect different resonant frequencies, the shape of the isosceles trapezoid can expand the absorption frequency as much as possible.

[0041] The first impedance layer employs a three-dimensional structure, which reduces the impact of the incident wave angle on the absorption effect, thereby achieving high angular stability.

[0042] The second metal layer with uniformly distributed resistance in the second impedance layer absorbs low-frequency electromagnetic waves, while the X-shaped slit transmits electromagnetic waves, i.e., transmits electromagnetic waves in the middle frequency band that pass through the absorber.

[0043] The first and second impedance layers have absorption effects in different frequency bands, and both have good angular stability within their respective absorption frequency bands.

[0044] The gaps in the third metal layer of the second impedance layer are exactly the same as those in the frequency-selective surface layer, allowing for wave transmission in the same frequency band. By changing the size of the gaps, the transmission frequency can be altered, making the transmission frequency band located between the absorption frequency bands of the first and second impedance layers. Simultaneously, while maintaining the absorption effect of the second impedance layer, the first impedance layer adjusts the impedance matching between the air and the second impedance layer, further improving the relative bandwidth and angular stability of the second impedance layer's absorption, thus achieving absorption characteristics with high angular stability.

[0045] By adjusting the two heights of the first metal layer on the first impedance layer to the frequency selective surface layer and the second impedance layer to the frequency selective surface layer, as well as the dimensional parameters of the specific structure of the breathable integrated material, its impedance characteristics can be well matched with air, achieving good absorption characteristics at low and high frequencies.

[0046] In a preferred configuration, the first dielectric layer, the second dielectric layer, and the third dielectric layer are all the same size, preferably 24mm × 24mm; wherein the height of the first dielectric layer is 14mm, and the distance between the second dielectric layer and the third dielectric layer is preferably 8mm. Specific implementation examples:

[0048] An ATA-type absorber-permeable integrated material with high angular stability comprises n × n structural units, as shown in the schematic diagram of the structural unit. Figure 1 As shown, it consists of a three-layer structure, from top to bottom: a first impedance layer 1, a second impedance layer 4, and a frequency selective surface layer 9. The first impedance layer 1 is directly connected to the second impedance layer 4. The first impedance layer 1 has dimensions of 24 mm × 24 mm and includes a first dielectric layer 2 and a first metal layer located on the upper surface of the first dielectric layer. The first dielectric layer 2 has a thickness of 0.8 mm and a height of 14 mm, and is made of FR4 (glass fiber epoxy resin copper clad laminate). A schematic diagram of the first metal layer is shown below. Figure 2 As shown, there are eight metal grid strip structures 3, printed on the sides of the cubic dielectric layer. Each cube has metal grid strips printed on two sides. The four cubes are identical. Each grid strip consists of 20 horizontal metal strips of progressively increasing length and a vertical metal strip located in the middle of the horizontal metal strips. From top to bottom, the length of the first horizontal metal strip is 3.2 mm, increasing by 0.4 mm each time. The length of the twentieth metal strip is 10.8 mm. The length of the vertical metal strip connecting the 20 metal strips is 7.8 mm. The width of each metal strip is 0.2 mm. The distance from the twentieth metal strip to the second impedance layer 4 is 3.2 mm.

[0049] A schematic diagram of the structure of the second impedance layer 4 is shown below. Figure 3As shown, its dimensions are 24 mm × 24 mm; the second impedance layer 4 includes a second dielectric layer 8, a second metal layer 5 located on the upper surface of the second dielectric layer, a resistor structure 6 located inside the second metal layer 5, and a third metal layer 7 located inside the second metal layer 5. The second dielectric layer 8 has a thickness of 0.254 mm, dimensions of 24 mm × 24 mm, and is made of Rogers RO4350B material. The second metal layer 5 is a square metal ring structure, with a metal portion width of 1 mm and an overall square side length of 20 mm. The resistor structure 6 located inside the second metal layer has a slot width of 0.5 mm, and the spacing between each resistor is 1.6 mm. The third metal layer 7 contains a bent X-shaped slit structure. The slit can be divided into four identical sides. Each side is formed by connecting the ends of a right-angled zigzag slit with a length of 0.9 mm and a width of 0.4 mm. There are a total of 9 right-angled zigzag slits. At the outermost edge of each side is a rectangular end slit. The size of the end slit is larger than the right-angled zigzag slits, with a length of 3 mm and a width of 0.8 mm.

[0050] The frequency selective surface layer 9 includes a third dielectric layer and a fourth metal layer 10 located on the upper surface of the third dielectric layer; wherein, the third dielectric layer is made of Rogers RO4350B material with a thickness of 0.254 mm and a size of 24 mm × 24 mm. The gap structure inside the fourth metal layer is exactly the same as the gap structure inside the third metal layer, corresponding vertically.

[0051] The dimensions mentioned above are specific dimensions that have been calculated and optimized. If the dimensions change, the breathability will deteriorate.

[0052] Figure 5 The electromagnetic simulation results of the integrated absorbent and permeable material of the present invention in electromagnetic simulation software, using periodic boundary conditions, are shown in the figure when electromagnetic waves are incident perpendicularly. Part a is the TE mode and part b is the TM mode. Figure 4 The horizontal axis represents frequency, and the vertical axis represents S-parameters. From Figure 5 As can be seen, the integrated absorber-transmitter material of this invention exhibits dual polarization characteristics when electromagnetic waves are incident perpendicularly. Specific data are as follows: under perpendicular incidence, the integrated absorber-transmitter material of this invention absorbs waves in the ranges of 2.21-3.59 GHz and 8.43-11.62 GHz, with a relative bandwidth of 47.59% + 31.82% = 79.41%, and transmits waves at 5.65 GHz with an insertion loss of 0.88 dB.

[0053] Figure 5 The S11 curve represents the reflection coefficient, and the S21 curve represents the transmission coefficient.

[0054] Figure 6The figures show the electromagnetic simulation results of the integrated absorbent material of the present invention under incident waves at different angles. Part a is the TE mode and part b is the TM mode. Figure 6 The horizontal axis represents frequency, and the vertical axis represents S11 parameters. Specific data is as follows: In TE mode, with an incident angle of 0-60°, the integrated absorber-penetrator material of this invention absorbs waves in the 2.23-3.59GHz and 8.43-10.46GHz ranges, with a relative bandwidth of 46.73% + 21.49% = 68.22%; in TM mode, with an incident angle of 0-30°, the integrated absorber-penetrator material of this invention absorbs waves in the 2.4-3.59GHz and 8.43-11.2GHz ranges, with a relative bandwidth of 39.73% + 28.22% = 67.95%.

[0055] Figure 7 This is a calculation chart showing the absorption rate of the integrated absorber material of this invention under two polarizations for incident waves at different angles. Figure 7 It can be seen that within the operating frequency range where the S11 parameter is below -10dB, the absorption rate is greater than 80%, which meets the absorption requirements.

[0056] The integrated absorber-permeable material proposed in this invention has dimensions of 24 mm × 24 mm and a maximum operating wavelength of 135.75 mm. Its unit size is less than one-fifth of the wavelength, exhibiting miniaturization characteristics. By utilizing the different heights of the two impedance layers to the frequency-selective surface layer, frequency band absorption is achieved. The heights correspond to the center frequencies of the two absorption frequencies, and the absorption frequency band can be shifted by adjusting the heights. The integrated absorber-permeable material proposed in this invention achieves a maximum angular stability of 60°, exhibiting high angular stability characteristics superior to existing reported literature.

[0057] The foregoing descriptions are preferred embodiments of the present invention. Unless there is a clear contradiction between the preferred embodiments or a prerequisite for a particular preferred embodiment, the preferred embodiments can be arbitrarily combined and used. The embodiments and specific parameters described are only for clearly illustrating the inventor's invention verification process and are not intended to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention shall still be determined by its claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. An ATA - type integrated suction and penetration structural unit with high angular stability, characterized in that , including a first impedance layer, a second impedance layer, and a frequency selective surface layer arranged from top to bottom; The first impedance layer is composed of 4 identical cubic structures with upper and lower openings in a cross shape. The side surface of the cube is the first dielectric layer, and the outer surfaces of two adjacent side surfaces of the same cube are attached with a first metal layer; The first metal layer includes a plurality of horizontal metal strip arrays arranged in an isosceles trapezoid shape with increasing lengths from top to bottom and parallel and equally spaced, and vertical metal strips vertically connecting the midpoints of all horizontal metal strips; The second impedance layer includes a rectangular second dielectric layer, a square ring-shaped second metal layer on the upper surface of the second dielectric layer, and a third metal layer on the upper surface of the second dielectric layer and surrounded by the second metal layer; The same number of identical resistors are evenly distributed on each side of the second metal layer; An X-shaped gap composed of four sub-gaps is opened in the middle of the third metal layer. The sub-gap is formed by connecting a plurality of right-angled folded line gaps and end gaps. The connections of the right-angled folded line gaps are perpendicular to each other. The outer ends of the sub-gaps are vertically connected with the end gaps whose width is greater than the width of the right-angled folded line gaps. The inner ends of the four sub-gaps are cross-connected together in a cross shape; The frequency selective surface layer includes a third dielectric layer and a fourth metal layer on the upper surface of the third dielectric layer; A metal gap with the same shape and position as the X-shaped gap is opened on the fourth metal layer; The first impedance layer is connected to the second impedance layer, and the air medium is between the second impedance layer and the frequency selective surface layer.

2. The suction-through integrated structural unit according to claim 1, wherein The planar projection sizes of the first impedance layer, the second impedance layer, and the frequency selective surface layer are the same.

3. The integrated suction and penetration structural unit according to claim 1, characterized in that The first dielectric layer is an epoxy glass fiber board, and the materials of the second dielectric layer and the third dielectric layer are Rogers RO4350B.

4. The integrated suction and penetration structural unit according to claim 1, wherein The first dielectric layer, the second dielectric layer, and the third dielectric layer are all 24mm×24mm squares; The height of the first dielectric layer is 14mm, and the distance between the second dielectric layer and the third dielectric layer is 8mm.

5. The integrated suction and penetration structural unit according to claim 1, wherein The length of the top horizontal metal strip in the first metal layer is 3.2mm, each lower horizontal metal strip is 0.4mm larger than the upper metal strip, the length of the vertical metal strip is 7.8mm, the width of each metal strip is 0.2mm, and the distance from the bottom horizontal metal strip to the second impedance layer (4) is 3.2mm.

6. The integrated suction and penetration structural unit according to claim 1, wherein Among them, the thicknesses of the second dielectric layer (8) and the third dielectric layer are both 0.254mm. The side length of the square ring formed by the second metal layer (5) is 20mm, and the width is 1mm. The gap width of the resistor (6) located inside the second metal layer is 0.5mm, and the distance between each resistor is 1.6mm; The sub-gap is formed by connecting nine right-angled folded line gaps with a length of 0.9mm and a width of 0.4mm end to end. The length of the end gap is 3mm, and the width is 0.8mm.

7. An ATA type integrated suction and penetration material with high angular stability, characterized in that, Including N 2 structural units as described in any one of claims 1 to 6, arranged in a square shape, where N is an integer greater than 1.

Images