Polarization conversion wave-absorbing ultra-wideband stealth metasurface structure

Abstract

The invention discloses a polarization conversion wave-absorbing ultra-wideband stealth metasurface structure which comprises a polarization conversion layer, a first filling layer, a frequency selection surface layer, a second filling layer and a wave-absorbing layer which are sequentially arranged from top to bottom. The polarization conversion layer comprises a polarization conversion patch, the polarization conversion patch comprises a plurality of 2 * 2 subarrays, and the angle arrangement difference between adjacent 2 * 2 units is 90 degrees. The frequency selective surface layer comprises a first patch, a second patch and a third patch which are sequentially arranged from top to bottom. The wave absorbing layer comprises a resistive film patch, and the impedance of the wave absorbing layer is matched with that of the second filling layer.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic supersurfaces, and in particular to a polarization conversion wave-absorbing ultra-wideband stealth supersurface structure. Background Art

[0002] Radar Cross Section (RCS) is an important indicator to measure the stealth performance of aircraft. Reducing RCS can reduce the detection distance of the detection system, delay the time for the defense system to find the target, and reduce the probability of stealth aircraft being tracked and intercepted. The use of absorbing materials is an important technical means to reduce the RCS of stealth aircraft, which consumes the absorbed electromagnetic waves by converting them into heat or other forms of energy. Traditional absorbing materials are usually ferrites, carbon black, etc., but absorbing materials have shortcomings such as narrow absorption bandwidth, high density, high weight, and single absorption mechanism. Existing absorbing materials need to increase thickness to improve the stealth capability of low-frequency bands, which inevitably increases the load of stealth aircraft. The use of frequency selective surfaces conformal to the aircraft is another effective way to reduce RCS. The low RCS shape design of the aircraft can reflect the incident electromagnetic waves to the non-incoming direction, effectively reducing the RCS of a single station, but the RCS effect is significantly reduced for dual-warfare or multi-stations.

[0003] The prior art provides a radar stealth absorbing material and a preparation method thereof, which can achieve 5dB in the frequency range of 2.0GHz-12.0GHz. The prior art also provides a broadband metamaterial absorber that is insensitive to the incident angle, and the absorber structure achieves an absorption rate of more than 90% in the frequency band of 8.0GHz-15.0GHz (relative bandwidth is 61%). However, the prior art cannot meet the demand for stealth capabilities above high frequencies of 18.0GHz. Summary of the invention

[0004] The purpose of the present invention is to provide a polarization conversion absorbing ultra-wideband stealth metasurface structure, which has the characteristics of low-frequency broadband diffuse scattering, high-frequency broadband absorption, and large-angle stability. The stealth frequency band covers the 8-30GHz band and can significantly reduce the dual-station RCS.

[0005] In order to achieve the above-mentioned object, the present invention provides a polarization conversion absorbing ultra-wideband stealth metasurface structure, comprising: a polarization conversion layer, a first filling layer, a frequency selective surface layer, a second filling layer, and an absorbing layer arranged in sequence from top to bottom;

[0006] The polarization conversion layer includes a polarization conversion patch, and the polarization conversion patch includes a plurality of 2×2 sub-arrays, and the angle arrangement of adjacent 2×2 sub-arrays differs by 90°;

[0007] The frequency selective surface layer comprises: a first patch, a second patch, and a third patch arranged in sequence from top to bottom;

[0008] The impedance of the absorbing layer matches the impedance of the second filling layer.

[0009] Optionally, each of the 2×2 sub-arrays is composed of four polarization conversion units arranged in the same direction, and the periodic size of each polarization conversion unit is a;

[0010] Each polarization conversion unit includes: a middle microstrip line and two end microstrip lines arranged in parallel, the two end microstrip lines are respectively arranged on both sides of the middle microstrip line, the length of the middle microstrip line is greater than the length of the end microstrip line; and the width of the middle microstrip line is the same as the width of the two end microstrip lines.

[0011] Optionally, the first patch of the frequency selective surface layer includes a plurality of square first units with a period size of b, a square patch is provided at the geometric center of each of the first units, and the period size of each square patch is smaller than the period size of the first unit, and the edge of the square patch is parallel to the edge of the first unit;

[0012] The third patch includes a plurality of square third units with a period size of b, and the structure of each of the third units is the same as that of the first unit;

[0013] The second patch includes a plurality of square second units with a period size of b, and each of the second units includes: a Jerusalem cross patch and a square ring patch, wherein the Jerusalem cross patch and the square ring patch are both placed at the geometric center of the second unit, and the Jerusalem cross patch is located at the center of the square ring patch; the edges of the square ring patch are respectively parallel to the edges of the second unit, and the two long sides of the Jerusalem cross patch are respectively parallel to the edges of the second unit.

[0014] Optionally, the frequency selective surface layer further comprises:

[0015] An upper dielectric substrate is disposed between the first patch and the second patch, wherein the first patch and the second patch are respectively attached to two sides of the upper dielectric substrate, and the periodic size thereof is the same as the periodic size of the first patch and the second patch;

[0016] The lower dielectric substrate is arranged between the second patch and the third patch. The third patch is attached to the lower surface of the lower dielectric substrate, and its periodic size is the same as that of the third patch.

[0017] Optionally, the resistor film patch is arranged below the third patch, and comprises a plurality of square resistor units with a period size of c; and a square resistor film with the same resistance value is arranged at the geometric center of each resistor unit, and the size of the resistor film is smaller than the period size of the resistor unit.

[0018] Optionally, the geometric center of the polarization conversion layer and the geometric center of the wave absorbing layer are on the same axis.

[0019] Optionally, the absorbing layer further includes: an absorbing medium substrate and a bottom patch, wherein the bottom patch is a metal sheet; the resistive film patch and the bottom patch are respectively attached to two sides of the absorbing medium substrate, and the size of the absorbing medium substrate is the same as the periodic size of the resistive film patch and the bottom patch.

[0020] Optionally, the thickness of the first filling layer and the second filling layer are both in the range of 1-10 mm, and air or filling foam can be used.

[0021] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0022] (1) The polarization conversion layer and frequency selective surface layer of the metasurface structure described in the present invention work together to effectively reduce the RCS in the low-frequency band through phase cancellation between adjacent sub-arrays; the absorbing layer can completely absorb electromagnetic waves in the high-frequency band to achieve the purpose of stealth.

[0023] (2) The metasurface structure described in the present invention has a 180° reflection phase difference by arranging the adjacent 2×2 sub-arrays of the polarization conversion layer at an angle of 90°, and the symmetrical design of the frequency selective surface layer significantly reduces the dual-station (multi-station) RCS, which has broad application prospects in the fields of electromagnetic countermeasures and military stealth.

[0024] (3) The subunits of the metasurface structure described in the present invention are small in size, light in weight, easy to process, low in profile, and have good angular stability. The stealth frequency bandwidth can be changed by changing the periodic size of the subunits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the polarization conversion absorbing ultra-wideband stealth metasurface structure of the present invention.

[0026] Figure 2 This is a schematic structural diagram of the polarization conversion unit of the polarization conversion absorbing ultra-wideband stealth metasurface structure of the present invention.

[0027] Figure 3 It is a schematic diagram of the structure of several sub-arrays of the polarization conversion absorbing ultra-wideband stealth metasurface structure of the present invention.

[0028] Figure 4 This is a schematic structural diagram of the first and third units of the polarization conversion absorbing ultra-wideband stealth metasurface structure of the present invention.

[0029] Figure 5 This is a schematic structural diagram of the second unit of the polarization conversion absorbing ultra-wideband stealth metasurface structure of the present invention.

[0030] Figure 6 It is a schematic structural diagram of the resistance unit of the polarization conversion absorbing ultra-wideband stealth metasurface structure of the present invention.

[0031] Figure 7 This is a result diagram of the reflection phase of adjacent 2×2 sub-arrays of the metasurface structure in Example 1.

[0032] Figure 8 It is the reflection coefficient simulation result of the metasurface structure in Example 1 under the incidence of TE polarized electromagnetic wave.

[0033] In the figure, Ⅰ-polarization conversion layer, Ⅱ-frequency selective surface layer, Ⅲ-absorbing layer, 1-polarization conversion patch, 11-polarization conversion unit, 12-end microstrip line, 13-middle microstrip line, 2-polarization dielectric substrate, 3-first patch, 31-first unit, 32-square patch, 4-upper dielectric substrate, 5-second patch, 51-second unit, 52-square ring patch, 53-Jerusalem cross patch, 6-lower dielectric substrate, 7-third patch, 8-resistance film patch, 81-resistance unit, 82-resistance film, 9-absorbing dielectric substrate, 10-bottom patch. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] like Figure 1 As shown, the present invention provides a polarization conversion absorbing ultra-wideband stealth metasurface structure, comprising: a polarization conversion layer I, a first filling layer, a frequency selective surface layer II, a second filling layer, and an absorbing layer III arranged in sequence from top to bottom.

[0038] The thickness of the first filling layer and the second filling layer are both within the range of 1-10 mm, and air or filling foam can be used, which can improve the absorption bandwidth without increasing the weight of the material.

[0039] like Figure 1 As shown, a spatial coordinate system is established, the plane parallel to the surface of each layer of material is regarded as the xoy plane, and the horizontal and vertical directions parallel to the edge of the material surface are set as the y-axis and x-axis, and the z-axis is established in the direction perpendicular to the surface of each layer of material.

[0040] like Figure 3 As shown, the polarization conversion layer includes: a polarization conversion patch 1 and a polarization dielectric substrate 2. The polarization conversion patch 1 can realize polarization conversion in a low frequency and wide frequency range, and includes a plurality of 2×2 sub-arrays, and the arrangement angles between two adjacent 2×2 sub-arrays differ by 90°. Figure 3 As shown, when the polarization conversion layer I is composed of 4 2×2 subarrays, the 4 2×2 subarrays are marked as subarray 0, subarray 1, subarray 2, and subarray 3 in a clockwise direction, respectively. The subarray 1 is obtained by rotating the geometric center point of subarray 0 by 90° clockwise, the subarray 2 is obtained by rotating the geometric center point of subarray 1 by 90° clockwise, and the subarray 3 is obtained by rotating the geometric center point of subarray 2 by 90° clockwise. Since the arrangement angles between adjacent 2×2 subarrays differ by 90°, the surface currents of adjacent 2×2 subarrays are orthogonally distributed, so that there is a 180° reflection phase difference between adjacent 2×2 subarrays, and the amplitudes of the electromagnetic waves reflected by them are equal.

[0041] like Figure 2 As shown, each 2×2 subarray is composed of 4 polarization conversion units 11 arranged in the same direction, each polarization conversion unit 11 has a periodic size of a, and is composed of 3 microstrip lines arranged in parallel. Among them, the 3 microstrip lines are metal lines, including: a middle microstrip line 13, 2 end microstrip lines 12, and the 2 end microstrip lines 12 are respectively arranged on both sides of the middle microstrip line 13. And the widths of the 3 microstrip lines are the same, and the length of the middle microstrip line 13 is greater than the length of the end microstrip line 12.

[0042] The polarization dielectric substrate 2 is a carrier of the polarization conversion patch 1 . The polarization conversion patch 1 is attached to the upper surface of the polarization dielectric substrate 2 , and the periodic size of the polarization dielectric substrate 2 is the same as the periodic size of the polarization conversion patch 1 .

[0043] The frequency selective surface layer II includes: a first patch 3, an upper dielectric substrate 4, a second patch 5, a lower dielectric substrate 6, and a third patch 7 which are arranged in sequence from top to bottom.

[0044] The first patch 3 is arranged below the polarized dielectric substrate 2 and includes a plurality of square first units 31 with a periodic size of b, such as Figure 4 As shown, the edges of each of the first units 31 are parallel to the x-axis and the y-axis respectively; a square patch 32 is provided at the geometric center of each of the first units 31, and the size of each square patch 32 is smaller than the periodic size of the first unit 31, and the edges of the square patch 32 are parallel to the x-axis direction and the y-axis direction respectively, so that the structure of each of the first units 31 is symmetrical about the x-axis direction and the y-axis direction.

[0045] The third patch 7 includes a plurality of square third units with a period size of b, and the structure of each of the third units is the same as that of the first unit 31 .

[0046] The second patch 5 includes a plurality of square second units 51 with a period size of b, and the edges of each second unit 51 are parallel to the x-axis direction and the y-axis direction respectively; each second unit 51 includes: a Jerusalem cross patch 53 and a square ring patch 52, the Jerusalem cross patch 53 and the square ring patch 52 are both placed at the geometric center of the second unit 51, and the Jerusalem cross patch 53 is arranged at the center of the square ring patch 52; the edges of the square ring patch 52 are parallel to the x-axis direction and the y-axis direction respectively, and the two long sides of the Jerusalem cross patch 53 are parallel to the x-axis direction and the y-axis direction respectively, so that the structure of each second unit 51 is symmetrical about the x-axis direction and the y-axis direction. Since the structures of the first unit 31, the second unit 51 and the third unit are symmetrical about the x-axis direction and the y-axis direction, the frequency selective surface layer II can reflect low-frequency electromagnetic waves of horizontal polarization and vertical polarization, and can achieve broadband wave transmission in a wide frequency range of high frequency, and has good steep cutoff characteristics.

[0047] The upper dielectric substrate 4 is a carrier of the first patch 3 and the second patch 5. The first patch 3 and the second patch 5 are attached to the two sides of the upper dielectric substrate 4 respectively. The upper dielectric substrate 4 provides support for the first patch 3 and the second patch 5, and the periodic size of the upper substrate 4 is the same as the periodic size of the first patch 3 and the second patch 5. The lower dielectric substrate 6 is arranged between the second patch 5 and the third patch 7 and is a carrier of the third patch 7. The third patch 7 is attached to the lower surface of the lower dielectric substrate 6 and provides support for the third patch 7. The periodic size of the lower dielectric substrate 6 is the same as the periodic size of the third patch 7; and the upper dielectric substrate 4 and the lower dielectric substrate 6 are made of the same material and have the same thickness.

[0048] The absorbing layer III includes: a resistor film patch 8, an absorbing medium substrate 9 and a bottom patch 10 arranged in sequence from top to bottom. Figure 6 As shown, the resistor film patch 8 is arranged below the third patch 7, can provide a resistance value of 100-1000Ω, and includes a plurality of resistor units 81, each of which is a square with a period size of c, and a square resistor film 82 with the same resistance value is arranged at the geometric center of each resistor unit 81, and the size of the resistor film 82 is smaller than the period size of the resistor unit 81; by reducing the impedance Z of the resistor film patch 8 ω The difference between the impedance Z0 of the second filling layer between the frequency selective surface layer II and the absorbing layer III makes the reflection coefficient Γ of the resistor film patch 8 approach 0, as shown in Formula 1, and finally makes the impedance of the absorbing layer III match the impedance of the second filling layer, so that the electromagnetic waves incident on the resistor film patch 8 can be absorbed. The bottom patch 10 is a metal sheet, which is arranged at the bottom layer of the metasurface structure. Its size is consistent with the size of the resistor film patch 8, and it can absorb the electromagnetic waves in the high frequency band that the resistor film patch 8 cannot completely absorb. The absorbing medium substrate 9 is a carrier of the resistor film patch 8 and the bottom patch 10. The resistor film patch 8 and the bottom patch 10 are respectively attached to the two sides of the absorbing medium substrate 9 to provide support for the resistor film patch 8 and the bottom patch 10, and the size of the absorbing medium substrate 9 is the same as the periodic size of the resistor film patch 8 and the bottom patch 10.

[0049]

[0050] Among them, the impedance Z of the resistor film patch 8 is ω The calculation method is as follows:

[0051]

[0052] In the formula, μ ω is the magnetic permeability of the resistor film patch, ε ω is the conductivity of the resistor film patch.

[0053] Furthermore, the number of periods of the metasurface structure in the x-axis direction and the y-axis direction is consistent, and the periodic size a of the polarization conversion unit 11 in the polarization conversion layer I is the same as the periodic size c of the absorbing layer III, both of which are twice the periodic size b of the frequency selective surface layer II. And the geometric center of the polarization conversion layer I coincides with the geometric center of the absorbing layer III in the z-axis direction.

[0054] When electromagnetic waves are irradiated to the metasurface structure described in the present invention, low-frequency electromagnetic waves will be diffusely scattered on the polarization conversion layer I, and the low-frequency electromagnetic waves passing through the polarization conversion layer I will be irradiated to the frequency selective surface layer II. At the same time, the frequency selective surface layer II reflects the low-frequency electromagnetic waves, and completely intercepts the low-frequency electromagnetic waves in the electromagnetic waves. High-frequency electromagnetic waves will pass through the polarization conversion layer I and the frequency selective surface layer II to reach the absorbing layer III, and the absorbing layer III will completely absorb the high-frequency electromagnetic waves, so that the electromagnetic waves are completely intercepted to achieve the effect of stealth.

[0055] Embodiment 1

[0056] This embodiment will construct an overall size of 360×360×9.2mm 3 (length × width × height) stealth metasurface structure.

[0057] The polarization conversion patch 1 in the polarization conversion layer I is designed as a patch layer composed of 4 2×2 sub-arrays with different arrangement directions, and each polarization conversion unit 11 is square. The three microstrip lines in the polarization conversion unit 11 are parallel to the diagonal of the polarization conversion unit 11, and the microstrip lines are copper foils; the width W1 of each microstrip line is 0.5mm, and the length L1 of the middle microstrip line 13 is 9.0mm, the length L2 of the two end microstrip lines 12 is 4.0mm, and the spacing W2 between adjacent microstrip lines is 1.0mm. The polarization dielectric substrate 2 uses Rogers 5880, with a dielectric constant of 2.2, a loss tangent of 0.005, and a dielectric substrate thickness of 0.2mm.

[0058] The side length L3 of the square patch 32 in the first patch 3 and the third patch 7 of the frequency selective surface layer II is 1.2 mm. The long side length L4 of the Jerusalem cross patch 53 in the second patch 5 is 1.7 mm, the short side length L5 is 0.6 mm, and its line width W3 is 0.2 mm; the line width W4 of the square ring patch 52 in the second patch 5 is 0.8 mm. Among them, the square patch 32 of the first patch 3, the third patch 7, the square ring patch 52 and the Jerusalem cross patch 53 in the second patch 5 are all made of copper foil. The upper dielectric substrate 4 and the lower dielectric substrate 6 are both Arlon AD350, whose dielectric constant is 3.5, the loss tangent is 0.003, and the substrate thickness is 1.5 mm.

[0059] The size L5 of the resistor film 82 in the resistor unit 81 of the resistor film patch 8 is 8.5 mm, and the resistance R of the resistor film patch 8 is 200Ω. The bottom patch 10 is a copper foil and is attached to the surface of the absorbing dielectric substrate 9. The absorbing dielectric substrate 9 is Arlon AD350, which has a thickness of 1.5 mm, a dielectric constant of 3.5, and a loss tangent of 0.003.

[0060] Further, in this embodiment, the periodic size a of the polarization conversion unit 11 of the polarization conversion layer I and the periodic size c of the absorbing layer III are both set to 9 mm, and the periodic size b of the frequency selective surface layer II is set to 4.5 mm.

[0061] The first filling layer and the second filling layer are both air layers. The thickness of the first filling layer is 2.0 mm, and the thickness of the second filling layer is 2.5 mm.

[0062] Figure 7 This is a reflection phase result diagram of adjacent 2×2 sub-arrays of the polarization conversion layer I of this embodiment, proving that there is a 180° reflection phase difference between adjacent 2×2 sub-arrays.

[0063] Figure 8 This is the simulation result of the metasurface structure of this embodiment under the incidence of TE (Transverse Electric) polarized electromagnetic waves. In the frequency range of 8.0 to 18.0 GHz, the reflected electromagnetic waves undergo polarization rotation with the incident electromagnetic waves, and in the frequency range of 18.0 to 30 GHz, the electromagnetic waves are absorbed, which confirms that the metasurface structure of this embodiment can reduce RCS (Rich Communication Services) by phase cancellation between adjacent polarization conversion subarrays in the frequency range of 8.0 to 18.0 GHz, and reduce RCS by absorbing electromagnetic wave energy through the absorbing layer in the frequency range of 18 to 30 GHz, thereby achieving stealth covering the frequency range of 8.0 to 30.0 GHz.

[0064] The metasurface structure described in this embodiment is ultra-wideband stealth in the microwave band, and the metasurface structure described in the present invention can be adapted to stealth in other frequency bands by changing the periodic size of the subunits.

[0065] In summary, the polarization conversion layer and frequency selective surface layer of the metasurface structure described in the present invention work together to effectively reduce the RCS in the low-frequency band through phase cancellation between adjacent sub-arrays; the absorbing layer can completely absorb electromagnetic waves in the high-frequency band to achieve the purpose of stealth, and can significantly reduce the dual-station (multi-station) RCS, and has broad application prospects in the fields of electromagnetic confrontation and military stealth.

[0066] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A polarization conversion absorbing ultra-wideband stealth metasurface structure, characterized in that: include: A polarization conversion layer, a first filling layer, a frequency selective surface layer, a second filling layer, and an absorbing layer are arranged in sequence from top to bottom; The polarization conversion layer includes polarization conversion patches, and the polarization conversion patches include a plurality of 2×2 sub-arrays, and the angle arrangement between adjacent 2×2 sub-arrays differs by 90°; The frequency selective surface layer comprises: a first patch, a second patch, and a third patch arranged in sequence from top to bottom; The wave absorbing layer comprises a resistor film patch, and the impedance of the wave absorbing layer matches the impedance of the second filling layer.

2. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 1 is characterized in that: Each of the 2×2 sub-arrays is composed of four polarization conversion units arranged in the same direction, and the period size of each polarization conversion unit is a; Each polarization conversion unit includes: a middle microstrip line and two end microstrip lines arranged in parallel, the two end microstrip lines are respectively arranged on both sides of the middle microstrip line, and the length of the middle microstrip line is greater than that of the end microstrip line; And the width of the middle microstrip line is the same as the width of the two end microstrip lines.

3. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 1 is characterized in that: The polarization conversion layer further includes: a polarization dielectric substrate, the polarization conversion patch is attached to the upper surface of the polarization dielectric substrate, and the periodic size of the polarization dielectric substrate is the same as the periodic size of the polarization conversion patch.

4. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 1 is characterized in that: The first patch includes a plurality of square first units with a period size of b, a square patch is arranged at the geometric center of each of the first units, and the size of each square patch is smaller than the period size of the first unit, and the edge of the square patch is parallel to the edge of the first unit; The third patch includes a plurality of square third units with a period size of b, and the structure of each of the third units is the same as that of the first unit; The second patch includes a plurality of square second units with a period size of b, and each of the second units includes: a Jerusalem cross patch and a square ring patch, wherein the Jerusalem cross patch and the square ring patch are both placed at the geometric center of the second unit, and the Jerusalem cross patch is located at the center of the square ring patch; the edges of the square ring patch are respectively parallel to the edges of the second unit, and the two long sides of the Jerusalem cross patch are respectively parallel to the edges of the second unit.

5. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 4 is characterized in that: The frequency selective surface layer further comprises: An upper dielectric substrate is disposed between the first patch and the second patch, wherein the first patch and the second patch are respectively attached to two sides of the upper dielectric substrate, and the periodic size thereof is the same as the periodic size of the first patch and the second patch; The lower dielectric substrate is arranged between the second patch and the third patch. The third patch is attached to the lower surface of the lower dielectric substrate, and its periodic size is the same as that of the third patch.

6. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 4 is characterized in that: The resistor film patch is arranged below the third patch and includes a plurality of square resistor units with a period size of c; and a square resistor film with the same resistance value is arranged at the geometric center of each resistor unit, and the size of the resistor film is smaller than the period size of the resistor unit.

7. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 1 is characterized in that: The geometric center of the polarization conversion layer and the geometric center of the wave absorbing layer are on the same axis.

8. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 1 is characterized in that: The absorbing layer also includes: an absorbing medium substrate and a bottom patch, wherein the bottom patch is a metal sheet; the resistive film patch and the bottom patch are respectively attached to two sides of the absorbing medium substrate, and the periodic size of the absorbing medium substrate is the same as the periodic size of the resistive film patch and the bottom patch.

9. The polarization conversion absorbing ultra-wideband stealth metasurface structure according to claim 1, characterized in that: The thickness of the first filling layer and the second filling layer are both in the range of 1-10 mm, and air or filling foam can be used.

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