An ultra-wideband high-performance absorbing structure

Abstract

The present invention relates to the technical field of absorbing structures, and in particular to an ultra-wideband high-performance absorbing structure. The absorbing structure includes a first impedance layer, a first foam layer, a second impedance layer, a second foam layer, a third impedance layer, a third foam layer, and a metal layer; the first impedance layer is composed of a first periodic unit in a square shape, the first periodic unit includes a first patch-type structure, and the first patch-type structure includes a square ring-shaped patch-type structure; the second impedance layer is composed of a second periodic unit in a square shape, the second periodic unit includes a second patch-type structure, and the second patch-type structure includes a square ring-shaped patch-type structure; the third impedance layer is composed of a third periodic unit in a square shape, the third periodic unit includes a third patch-type structure, and the third patch-type structure includes a square ring-shaped patch-type structure. An embodiment of the present invention provides a structure that can achieve an absorbing effect of more than 20dB in ultra-wideband.

Description

Technical Field

[0001] The present invention relates to the technical field of wave absorbing structures, and in particular to an ultra-wideband high-performance wave absorbing structure. Background Art

[0002] Wave-absorbing structures can absorb electromagnetic waves and reduce electromagnetic wave scattering, and have broad application prospects in the fields of RCS reduction, electromagnetic compatibility design, and avoiding signal interference.

[0003] Traditional absorbing structures can usually only achieve -10dB absorption in a wide band or -20dB absorption in a narrow band, and cannot meet the requirements of both wide band and high absorption at the same time.

[0004] Therefore, in order to address the above shortcomings, it is necessary to provide a structure that can achieve an absorbing effect of more than -20dB in ultra-wideband. Summary of the Invention

[0005] The embodiment of the present invention provides an ultra-wideband high-performance absorbing structure, which can provide a structure that can achieve an absorbing effect of more than -20dB in the ultra-wideband when electromagnetic waves are incident at a large angle.

[0006] An embodiment of the present invention provides an ultra-wideband high-performance absorbing structure, which includes, in sequence along the thickness direction, a first impedance layer, a first foam layer, a second impedance layer, a second foam layer, a third impedance layer, a third foam layer, and a metal layer;

[0007] The first impedance layer is composed of square first periodic units periodically arranged along two adjacent sides thereof, wherein the minimum period of the arrangement is the side length of the first periodic unit, the first periodic unit includes a square electromagnetic film and a first patch-type structure provided on the electromagnetic film, wherein the first patch-type structure includes a square ring-shaped patch-type structure;

[0008] The second impedance layer is composed of second periodic units in a square shape periodically arranged along two adjacent sides thereof, wherein the minimum period of the arrangement is the side length of the second periodic unit, the second periodic unit includes a square electromagnetic film and a second patch-type structure provided on the electromagnetic film, and the second patch-type structure includes a square ring-shaped patch-type structure;

[0009] The third impedance layer is composed of square third periodic units periodically arranged along two adjacent sides thereof, wherein the minimum period of the arrangement is the side length of the third periodic unit, the third periodic unit includes a square electromagnetic film and a third patch-type structure provided on the electromagnetic film, and the third patch-type structure includes a square ring-shaped patch-type structure;

[0010] The ring widths of the first patch type structure, the second patch type structure and the third patch type structure decrease in sequence.

[0011] In one possible design, the side length of the first periodic unit is 5 mm, the outer side length of the first patch-type structure is 4.7 to 4.9 mm, and the ring width of the first patch-type structure is 1 to 2 mm;

[0012] The side length of the second periodic unit is 5 mm, the outer side length of the second patch type structure is 3.5 to 4.5 mm, and the ring width of the second patch type structure is 0.5 to 1 mm;

[0013] The side length of the third periodic unit is 5 mm, the outer side length of the third patch type structure is 3 to 4 mm, and the ring width of the third patch type structure is 0.1 to 0.3 mm.

[0014] In one possible design, the thickness of the first foam layer is 0.8 to 1.5 mm;

[0015] The thickness of the second foam layer is 0.8 to 1.5 mm;

[0016] The thickness of the third foam layer is 1.5 to 2.5 mm.

[0017] In a possible design, the electromagnetic film surface resistance of the first periodic unit is 150-250Ω / sq;

[0018] The electromagnetic film surface resistance of the second periodic unit is 150-250Ω / sq;

[0019] The electromagnetic film surface resistance of the third period unit is 250-350Ω / sq.

[0020] In a possible design, the first foam layer, the second foam layer, and the third foam layer are all made of PMI foam.

[0021] In a possible design, the first impedance layer, the first foam layer, the second impedance layer, the second foam layer, the third impedance layer, the third foam layer and the metal layer are bonded together by an adhesive layer.

[0022] In a possible design, the thickness of the adhesive layer is 0.09-0.15 mm.

[0023] In a possible design, the absorbing structure has two lowest reflectivity frequency points, namely 15-20 GHz and 32-37 GHz.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] In the present invention, the first, second, and third impedance layers, along with the metal layer, are composed of three types of periodic units: the first, second, and third periodic units. The patch-type structures within each periodic unit have different sizes and widths, decreasing from top to bottom. The periodic units composed of patch-type structures of different sizes and widths are periodically arranged to form an impedance loss array, or impedance layer. The impedance layer exhibits high transmittance, low reflectivity, and high heat conversion efficiency for electromagnetic waves in the corresponding frequency band. Electromagnetic waves passing through the three impedance layers are consumed. These consumed electromagnetic waves are reflected upon the metal layer and then re-enter the three impedance layers, where they are further absorbed by the loss, achieving a superior absorption effect.

[0026] In the present invention, a foam layer is sandwiched between the impedance layers or between the impedance layer and the metal layer. The foam layer has a low dielectric constant, close to that of air. The material is used in the structure mainly to play the role of spacing and support, achieving impedance matching in space, and at the same time has a certain dielectric loss effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of an ultra-wideband high-performance absorbing structure provided by an embodiment of the present invention;

[0029] Figure 2 is a structural diagram of a first periodic unit provided by an embodiment of the present invention;

[0030] Figure 3 is a structural diagram of a second periodic unit provided by an embodiment of the present invention;

[0031] Figure 4 is a schematic structural diagram of a third periodic unit provided by an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the wave absorbing effect of an ultra-wideband high-performance wave absorbing structure provided by an embodiment of the present invention.

[0033] In the picture:

[0034] 1-first impedance layer;

[0035] 11-first period unit;

[0036] 111-first patch type structure;

[0037] D1 - side length of the first periodic unit;

[0038] L1-the outer side length of the first patch type structure;

[0039] W1-ring width of the first patch type structure;

[0040] 2-first foam layer;

[0041] t1 - thickness of the first foam layer;

[0042] 3- second impedance layer;

[0043] 31-second period unit;

[0044] 311-second patch type structure;

[0045] D2 - side length of the second periodic unit;

[0046] L2-the outer side length of the second patch type structure;

[0047] W2-ring width of the second patch-type structure;

[0048] 4-Second foam layer;

[0049] t2 - thickness of the second foam layer;

[0050] 5- third impedance layer;

[0051] 51-3rd period unit;

[0052] 511-third patch type structure;

[0053] D3 - side length of the third period unit;

[0054] L3-the outer side length of the third patch-type structure;

[0055] W3- ring width of the third patch type structure;

[0056] 6- third foam layer;

[0057] t3 - thickness of the third foam layer;

[0058] 7-metal layer;

[0059] 8-adhesive layer;

[0060] t0-thickness of the adhesive layer. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0062] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" described in the embodiments of the present invention are described from the perspectives shown in the accompanying drawings and should not be understood as limiting the embodiments of the present invention. In addition, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" of another element, it can not only be directly connected "upper" or "lower" of the other element, but also indirectly connected "upper" or "lower" of the other element through an intermediate element.

[0064] like Figures 1 to 4 As shown, an embodiment of the present invention provides an ultra-wideband high-performance absorbing structure, which includes a first impedance layer 1, a first foam layer 2, a second impedance layer 3, a second foam layer 4, a third impedance layer 5, a third foam layer 6 and a metal layer 7 in the thickness direction;

[0065] The first impedance layer 1 is composed of square first periodic units 11 periodically arranged along two adjacent sides thereof. The minimum period of the arrangement is the side length of the first periodic unit 11. The first periodic unit 11 includes a square electromagnetic film and a first patch-type structure 111 provided on the electromagnetic film. The first patch-type structure 111 includes a square ring-shaped patch-type structure.

[0066] The second impedance layer 3 is composed of square second periodic units 31 periodically arranged along two adjacent sides thereof. The minimum period of the arrangement is the side length of the second periodic unit 31. The second periodic unit 31 includes a square electromagnetic film and a second patch-type structure 311 provided on the electromagnetic film. The second patch-type structure 311 includes a square ring-shaped patch-type structure.

[0067] The third impedance layer 5 is composed of square third periodic units 51 periodically arranged along two adjacent sides thereof. The minimum period of the arrangement is the side length of the third periodic unit 51. The third periodic unit 51 includes a square electromagnetic film and a third patch-type structure 511 provided on the electromagnetic film. The third patch-type structure 511 includes a square ring-shaped patch-type structure.

[0068] The ring widths of the first patch-type structure 111 , the second patch-type structure 311 , and the third patch-type structure 511 decrease in sequence.

[0069] In the present invention, the first impedance layer 1, the second impedance layer 3, the third impedance layer 5, and the metal layer 7 are composed of three types of periodic units: first periodic unit 11, second periodic unit 31, and third periodic unit 51. The patch-type structures in each periodic unit have different sizes and widths, which decrease from top to bottom. The periodic units composed of patch-type structures of different sizes and widths are periodically arranged to form an impedance loss array, i.e., an impedance layer. The impedance layer has high transmittance, low reflectivity, and high heat conversion rate for electromagnetic waves in the corresponding frequency band. Electromagnetic waves passing through the three impedance layers are consumed. The consumed electromagnetic waves are reflected after entering the metal layer 7 and re-enter the three impedance layers. The electromagnetic waves are then further absorbed by the loss, achieving a more excellent wave absorption effect.

[0070] In the present invention, a foam layer is sandwiched between the impedance layers or between the impedance layer and the metal layer 7. The foam layer has a low dielectric constant, close to that of air. The material is used in the structure mainly to play the role of spacing and support, achieving impedance matching in space, and at the same time has a certain dielectric loss effect.

[0071] It should be noted that the patch-type structure is fabricated by coating a thin layer of conductive material on the surface of the electromagnetic film. This layer is then etched to shape the coated layer, resulting in a thin, custom-shaped patch-type structure. The patch-type structure is extremely thin, approximately 0.05mm, and its thickness is negligible, not affecting the overall thickness of the impedance layer.

[0072] In some embodiments of the present invention, the side length of the first periodic unit 11 is 5 mm, the outer side length of the first patch-type structure 111 is 4.7 to 4.9 mm, and the ring width of the first patch-type structure 111 is 1 to 2 mm;

[0073] The side length of the second periodic unit 31 is 5 mm, the outer side length of the second patch type structure 311 is 3.5 to 4.5 mm, and the ring width of the second patch type structure 311 is 0.5 to 1 mm;

[0074] The side length of the third periodic unit 51 is 5 mm, the outer side length of the third patch type structure 511 is 3-4 mm, and the ring width of the third patch type structure 511 is 0.1-0.3 mm.

[0075] In this embodiment, the side length of the periodic unit, the shape of the patch-type structure, the outer side length, and the ring width are all important parameters for forming a special impedance array. Changing any of these parameters will change the impedance of the lossy array, thereby affecting the overall impedance of the absorbing material and ultimately the absorbing effect. Therefore, only when the parameters of the periodic unit of the three-layer impedance layer are within the above range can excellent broadband, high-performance absorbing effects be achieved.

[0076] In some embodiments of the present invention, the thickness of the first foam layer 2 is 0.8 to 1.5 mm;

[0077] The thickness of the second foam layer 4 is 0.8 to 1.5 mm;

[0078] The thickness of the third foam layer 6 is 1.5-2.5 mm.

[0079] In this embodiment, three foam layers separate the impedance layer and metal layer 7. The thickness of the foam layers determines the distance between the impedance layers or between the impedance layer and metal layer 7. Therefore, the thickness of the foam layers directly affects the impedance and absorption performance of the stacked impedance layers. Controlling the thickness of each foam layer within the above range can further achieve excellent broadband, high-performance absorption. Varying the thickness of each foam layer will also affect the performance of the stacked impedance layers, directly affecting the absorption performance.

[0080] In some embodiments of the present invention, the surface resistance of the electromagnetic film of the first periodic unit 11 is 150-250Ω / sq;

[0081] The surface resistance of the electromagnetic film of the second periodic unit 31 is 150-250Ω / sq;

[0082] The electromagnetic film surface resistance of the third period unit 51 is 250-350Ω / sq.

[0083] In this embodiment, the surface resistance of the electromagnetic film also affects the overall impedance of the absorbing material. When the surface resistance of the electromagnetic film of each impedance layer is within the above parameter range, an excellent absorbing effect can be achieved.

[0084] In some embodiments of the present invention, the materials used to prepare the first foam layer 2 , the second foam layer 4 , and the third foam layer 6 all include PMI foam.

[0085] In this embodiment, the foam layer has a low dielectric constant, close to that of air, and thus achieves impedance matching in space.

[0086] In some embodiments of the present invention, the first impedance layer 1 , the first foam layer 2 , the second impedance layer 3 , the second foam layer 4 , the third impedance layer 5 , the third foam layer 6 and the metal layer 7 are bonded together by an adhesive layer 8 .

[0087] In this embodiment, in order to make the layers fit closely together without affecting the overall impedance of the absorbing material, the layers are attached by applying a glue layer 8 .

[0088] In some embodiments of the present invention, the thickness of the adhesive layer 8 is 0.09-0.15 mm.

[0089] In this embodiment, in order to tightly bond the layers without causing a significant change in the distance between the layers, the thickness of the adhesive layer 8 is controlled to be 0.09-0.15 mm.

[0090] In some embodiments of the present invention, the wave absorbing structure has two lowest reflectivity frequency points, namely 15-20 GHz and 32-37 GHz.

[0091] f1 (15-20GHz) and f2 (32-37GHz) are the frequencies with the lowest reflectivity. Figure 5 , 14GHz-40GHz are all less than -20dB, achieving ultra-wideband absorption. The absorption frequency band will change with parameter adjustment, and ultra-wideband absorption with a bandwidth exceeding 20GHz can be achieved.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An ultra-wideband high-performance absorbing structure, characterized in that: The structure comprises, in sequence along the thickness direction, a first impedance layer (1), a first foam layer (2), a second impedance layer (3), a second foam layer (4), a third impedance layer (5), a third foam layer (6), and a metal layer (7); The first impedance layer (1) is composed of first periodic units (11) in a square shape periodically arranged along two adjacent sides thereof, wherein the minimum period of the arrangement is the side length of the first periodic unit (11), the first periodic unit (11) comprises a square electromagnetic film and a first patch-type structure (111) arranged on the electromagnetic film, and the first patch-type structure (111) comprises a square ring-shaped patch-type structure; The second impedance layer (3) is composed of second periodic units (31) in a square shape periodically arranged along two adjacent sides thereof, wherein the minimum period of the arrangement is the side length of the second periodic unit (31), the second periodic unit (31) comprises a square electromagnetic film and a second patch-type structure (311) arranged on the electromagnetic film, and the second patch-type structure (311) comprises a square ring-shaped patch-type structure; The third impedance layer (5) is composed of square third periodic units (51) periodically arranged along two adjacent sides thereof, wherein the minimum period of the arrangement is the side length of the third periodic unit (51), the third periodic unit (51) comprises a square electromagnetic film and a third patch-type structure (511) arranged on the electromagnetic film, and the third patch-type structure (511) comprises a square ring-shaped patch-type structure; The ring widths of the first patch-type structure (111), the second patch-type structure (311), and the third patch-type structure (511) decrease in sequence; The side length of the first periodic unit (11) is 5 mm, the outer side length of the first patch-type structure (111) is 4.7 to 4.9 mm, and the ring width of the first patch-type structure (111) is 1 to 2 mm; The side length of the second periodic unit (31) is 5 mm, the outer side length of the second patch-type structure (311) is 3.5 to 4.5 mm, and the ring width of the second patch-type structure (311) is 0.5 to 1 mm; The side length of the third periodic unit (51) is 5 mm, the outer side length of the third patch-type structure (511) is 3 to 4 mm, and the ring width of the third patch-type structure (511) is 0.1 to 0.3 mm; The thickness of the first foam layer (2) is 0.8-1.5 mm; The thickness of the second foam layer (4) is 0.8-1.5 mm; The thickness of the third foam layer (6) is 1.5-2.5 mm; The electromagnetic film surface resistance of the first periodic unit (11) is 150-250Ω / sq; The electromagnetic film surface resistance of the second periodic unit (31) is 150-250Ω / sq; The electromagnetic film surface resistance of the third periodic unit (51) is 250-350Ω / sq.

2. The wave absorbing structure according to claim 1, characterized in that: The materials used to prepare the first foam layer (2), the second foam layer (4) and the third foam layer (6) all include PMI foam.

3. The wave absorbing structure according to claim 1, characterized in that: The first impedance layer (1), the first foam layer (2), the second impedance layer (3), the second foam layer (4), the third impedance layer (5), the third foam layer (6) and the metal layer (7) are bonded together via an adhesive layer (8).

4. The wave absorbing structure according to claim 3, characterized in that: The thickness of the adhesive layer (8) is 0.09-0.15 mm.

5. The wave absorbing structure according to claim 1, characterized in that: The wave absorbing structure has two lowest reflectivity frequency points, namely 15-20 GHz and 32-37 GHz.

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