P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials

Abstract

The present invention belongs to the technical field of absorbing materials, and specifically relates to a P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials. The structure comprises a plurality of periodically arranged basic units, wherein the basic units comprise a stacked and connected reflector plate and a dielectric plate. The dielectric plate is provided with a functional unit, and the functional unit comprises an outer closed-loop patch and an inner closed-loop patch located within the outer closed-loop patch. The outer closed-loop patch has at least two protruding corners, a concave area is provided between the protruding corners, a connecting patch is connected between the concave area and the inner closed-loop patch, a middle closed-loop patch is further provided within the protruding corners, and energy dissipation components are provided on the outer closed-loop patch and / or the connecting patch. The present invention has the advantages of light weight and low cost while ensuring high bandwidth and a low profile.

Description

Technical Field

[0001] The present invention belongs to the technical field of absorbing materials, and in particular relates to a P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials. Background Art

[0002] Metamaterials refer to composite materials that precisely control physical fields at the subwavelength scale through artificial microstructures. Electromagnetic metamaterials are an emerging class of synthetic materials. By leveraging the electromagnetic induction between subwavelength unit structures and electromagnetic waves and utilizing electromagnetic resonance properties to design different structures, they can manipulate the amplitude, phase, and polarization of electromagnetic waves. Amplitude manipulation can be used to effectively absorb electromagnetic waves. By loading resistors, the energy of electromagnetic waves can be converted into heat through the thermal effects of the resistors. In industries such as communications, there is a significant demand for electromagnetic testing. Researchers need to construct microwave anechoic chambers as test spaces, and the design and application of absorbing materials are crucial to anechoic chamber performance. Metamaterial structures with absorbing properties offer advantages such as simplicity, low profile, light weight, and high bandwidth, making them a research hotspot for anechoic chamber absorbing material design. In recent years, with the rapid development of low-frequency detection technology, efficient electromagnetic absorbing metamaterial structures operating in the P-band have become crucial for reducing the detectability of characteristic signals.

[0003] While increasing the size and thickness can appropriately lower the operating frequency of metamaterial absorbing structures, ensuring strong absorbing performance and bandwidth in the P-band remains challenging. Currently, most absorbing structures operate in the S-Ku band, and their stealth performance is insufficient to counter anti-stealth technologies like low-frequency detection. Their stealth effectiveness is significantly reduced if they encounter P / L-band radar, thus limiting their application. Some metamaterial absorbing structures operating in the P-band have a narrow bandwidth and cannot effectively meet absorbing performance requirements. To achieve bandwidth expansion, some P-band absorbing structures utilize magnetic materials or a combination of magnetic materials and metamaterials. Magnetic materials have high magnetic permeability, which can broaden the absorber's bandwidth while maintaining a relatively small thickness. However, these materials are heavy, costly, and difficult to conform to, limiting their application. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials, which has the advantages of light weight and low cost while ensuring high bandwidth and low profile.

[0005] An embodiment of the present invention provides a P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials, comprising a plurality of periodically arranged basic units, wherein the basic units include a stacked reflector plate and a dielectric plate, wherein a functional unit is provided on the dielectric plate, and wherein the functional unit includes an outer closed-loop patch and an inner closed-loop patch located inside the outer closed-loop patch, wherein the outer closed-loop patch has at least two protruding corners, a concave area is provided between the protruding corners, a connecting patch is connected between the concave area and the inner closed-loop patch, a middle closed-loop patch is further provided inside the protruding corner, and energy dissipation parts are provided on the outer closed-loop patch and / or the connecting patch.

[0006] In one embodiment, the reflective plate is a metal plate, the functional unit is made of a metal material, and the energy dissipation component is a resistor.

[0007] The closed-loop patch refers to a structure that is itself a closed loop, and the patch refers to a strip made of a conductive material (such as metal, which can be copper); the protruding corner refers to the part that protrudes from the outer closed-loop patch. Since it protrudes from the outer closed-loop patch, there is a concave area between the protruding corners. The protruding corners and the concave area are both distinguished relative to the center of the outer closed-loop patch, that is, the protruding corners are farther away from the center of the outer closed-loop patch than the concave area.

[0008] In one embodiment, the end of the connecting patch is located inside the inner closed-loop patch.

[0009] In one embodiment, a sealing patch is provided at the end of the connecting patch.

[0010] In one embodiment, the protruding angles are evenly distributed around the center point of the functional unit, and the center of the inner closed-loop patch is the center point of the functional unit.

[0011] In one embodiment, the protruding corner is in an arc shape, the middle closed-loop patch is in a circular shape, and the inner closed-loop patch is in a rectangular shape.

[0012] In one embodiment, the protruding corner is in the shape of a 3 / 4 circular ring, and the inner closed-loop patch is in the shape of a square.

[0013] In one embodiment, the number of the protruding corners is four, the number of the middle closed-loop patches is four, and the number of the connecting patches is four.

[0014] In one embodiment, the energy-consuming parts are evenly distributed around the center point of the functional unit.

[0015] In one embodiment, the middle closed-loop patch is not connected to the outer closed-loop patch or the inner closed-loop patch.

[0016] The beneficial effect of the present invention is that the present invention converts the energy of the incident electromagnetic wave into heat energy by loading a lumped resistor through the regulation of the amplitude of the electromagnetic wave, thereby achieving effective absorption of the electromagnetic wave. The structure has two resonant frequencies, and the absorption bandwidth is broadened by coupling of multiple resonant frequencies. Compared with the structure that uses magnetic materials and utilizes magnetic loss to achieve wave absorption, the structure uses lumped resistors and utilizes the electric loss characteristics to achieve wave absorption performance. In air, the wave impedance of a plane wave is approximately 377 ohms, and the electric field strength is approximately 377 times the magnetic field strength. The structure based on the electric loss characteristics can more effectively convert and absorb the energy of the electromagnetic wave. Therefore, the present structure can still ensure good absorption bandwidth and performance without using magnetic materials.

[0017] The low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials of the present invention mainly operates in the P-band, can achieve good absorbing performance from 372.2MHz to 1377.4MHz, and realize the purpose of electromagnetic stealth. While ensuring high bandwidth and low profile, it has the advantages of light weight, low cost and conformability.

[0018] This absorbing structure operates in the P-band. Because it doesn't use magnetic materials, it maintains high bandwidth and a low profile while being lightweight and cost-effective, making it suitable for countering anti-stealth technologies like low-frequency detection. Furthermore, because the dielectric substrate of the absorbing structure is only 0.254 mm thick, the metal plate is only 0.2 mm thick, and the space between the dielectric plate and the reflector is filled with air or foam, the structure is flexible and can conform to curved surfaces, making it suitable for absorbing curved turntable surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 For the three-dimensional schematic diagram of the square unit structure and the metal plate unit structure in the present invention, a rectangular coordinate system is established. Representing spatial relationships;

[0020] Figure 2 is a schematic structural diagram of the metal micro unit 12 and the resistor 19;

[0021] Figure 3 In the high-frequency electromagnetic full-wave simulation software CST, when the TE wave and TM wave are incident on the electromagnetic model, the reflection coefficient S that varies with frequency is obtained. 11 Simulation results; TE wave (i.e., s-wave): has a magnetic field component but no electric field component in the propagation direction, which is called a transverse electric wave; TM wave (i.e., p-wave): has an electric field component but no magnetic field component in the propagation direction, which is called a transverse magnetic wave;

[0022] Figure 4 It is the simulation result of the reflection coefficient when the TE wave enters the electromagnetic model at different angles, where the incident angle is θ They are 0°, 15°, 30° and 45° respectively;

[0023] Figure 5 is the simulation result of the reflection coefficient when the TM wave enters the electromagnetic model at different angles; θ They are 0°, 15°, 30° and 45° respectively;

[0024] Figure 6 These are the simulation results of the frequency-dependent absorption coefficient A obtained when the TE wave and TM wave are incident on the electromagnetic model respectively.

[0025] In the figure, 10 is a unit element, 11 is a dielectric plate, 12 is a functional unit, 19 is an energy dissipation element, and 22 is a reflector.

[0026] 13 outer closed-loop patch, 14 middle closed-loop patch, 15 inner closed-loop patch, 16 inner concave patch, 17 connecting patch, 18 end-sealing patch. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] A metamaterial-based P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure comprises a plurality of periodically arranged basic units, each comprising a stacked reflector plate 22 and a dielectric plate 11. A functional unit 12 is provided on the dielectric plate 11. The functional unit 12 comprises an outer closed-loop patch 13 and an inner closed-loop patch 15 located within the outer closed-loop patch 13. The outer closed-loop patch 13 has at least two protruding corners, a concave area is provided between the protruding corners, a connecting patch 17 is connected between the concave area and the inner closed-loop patch 15, a middle closed-loop patch 14 is further provided within the protruding corners, and an energy dissipation component 19 is provided on the outer closed-loop patch 13 and / or the connecting patch 17.

[0030] The reflective plate 22 is a metal plate, the functional unit 12 is made of metal material, and the energy dissipation component 19 is a resistor.

[0031] The end of the connecting patch 17 is located inside the inner closed-loop patch 15 .

[0032] A sealing patch 18 is provided at the end of the connecting patch 17 .

[0033] The protruding angles are evenly distributed around the center point of the functional unit 12 , and the center of the inner closed-loop patch 15 is the center point of the functional unit 12 .

[0034] The protruding corner is in an arc shape, the middle closed-loop patch 14 is circular, and the inner closed-loop patch 15 is rectangular.

[0035] The protruding corner is in the shape of a 3 / 4 circular ring, and the inner closed-loop patch 15 is in the shape of a square.

[0036] The number of the protruding corners is four, the number of the middle closed-loop patches 14 is four, and the number of the connecting patches 17 is four.

[0037] The energy consuming parts 19 are evenly distributed around the center point of the functional unit 12 .

[0038] The middle closed-loop patch 14 is not connected to the outer closed-loop patch 13 or the inner closed-loop patch 15 .

[0039] Specifically, such as Figure 1 As shown, the unit element 10 is a square, and the unit element 10 includes a dielectric plate 11, a functional unit 12 attached to the upper surface of the dielectric plate 11, and an energy dissipation component 19, which is a resistor;

[0040] The functional unit 12 can be obtained by etching on the metal foil layer.

[0041] like Figure 2 As shown, the functional unit 12 is composed of an outer closed-loop patch 13, a middle closed-loop patch 14, an inner closed-loop patch 15, and a combined shape of a concave patch 16, a connecting patch 17 and a sealing patch 18 formed after etching on a metal foil; the outer closed-loop patch 13 is composed of four identical 3 / 4 circular patches in a symmetrical form; the middle closed-loop patch 14 is composed of four identical circular patches in a symmetrical form; the concave patch 16, the connecting patch 17 and the sealing patch 18 have three different sizes and are respectively composed of four identical rectangular patches in a symmetrical form; the resistor includes a first resistor and a second resistor; the first resistor and the second resistor are respectively composed of four identical resistors in a symmetrical form.

[0042] The centers of the outer closed-loop patch 13 and the middle closed-loop patch 14 coincide with each other; the center of the inner closed-loop patch 15 coincides with the center of the functional unit 12;

[0043] The rectangular shape of the dielectric plate 11 and the reflective plate 22 has a side length, that is, a period of the unit element 10, of 95 mm to 100 mm.

[0044] The protruding corner of the outer closed-loop patch 13, that is, the inner radius of the 3 / 4 circular patch is 18 mm-22 mm, and the width is 1.9 mm-2.1 mm; the inner radius of the middle closed-loop patch 14 is 10 mm-12 mm, and the width is 3.2-3.6 mm; the inner side length of the inner closed-loop patch 15 is 14 mm-16 mm, and the width is 1.9 mm-2.1 mm.

[0045] The length of the concave patch 16 is 15 mm to 20 mm, the length of the connecting patch 17 is 16 mm to 19 mm, and the length of the end-sealing patch 18 is 4.8 mm to 5.1 mm; the width of all patches is 1.9 mm to 2.1 mm.

[0046] The resistance of the first resistor located on the protruding corner ranges from 163 ohms to 168 ohms, and the resistance of the second resistor located on the connecting patch 17 ranges from 758 ohms to 762 ohms.

[0047] The thickness of the dielectric plate 11 is 0.254 mm, the thickness of the functional unit 12 , ie, the metal foil layer, is 0.035 mm, and the distance between the unit element 10 and the reflective plate 22 ranges from 64.7 mm to 65.2 mm.

[0048] The non-conductive material used to make the dielectric substrate is F4BTMS430, a product of Taizhou ** Insulation Material Factory, with a relative dielectric constant of 4.30 and a dielectric loss of 0.0015. The metal foil layer can be made of any of the metal foils, gold foil, silver foil, or copper foil.

[0049] At 372.2MHz~600MHz and 900MHz~1200MHz, the outer closed-loop patch 13, the middle closed-loop patch 14, and the first resistor form a series resonant circuit to achieve the wave absorption function in this frequency band. At 600MHz~900MHz, the outer closed-loop patch 13, the second resistor, and the combined shape of the inner concave patch 16, the connecting patch 17, and the end-capping patch 18 form a series resonant circuit to achieve the wave absorption function in this frequency band. At 1200MHz~1377.4MHz, the outer closed-loop patch 13, the middle closed-loop patch 14, the inner closed-loop patch 15, the first resistor, the second resistor, and the combined shape of the inner concave patch 16, the connecting patch 17, and the end-capping patch 18 form a series resonant circuit to achieve the wave absorption function in this frequency band. At the same time, the above-mentioned symmetrical structures are all symmetrical about the center of the unit element 10 to achieve a full-polarization characteristic with stable transmission performance when irradiated by various polarized electromagnetic waves.

[0050] Example 2

[0051] In the high-frequency electromagnetic full-wave simulation software CST, when TE wave and TM wave are incident on the electromagnetic model, the reflection coefficient S that varies with frequency is obtained. 11 The simulation results, such as Figure 3 As shown. -10 The reflection coefficient band is from 372.2 MHz to 1377.4 MHz, with a relative bandwidth of 140 Due to the high symmetry of the absorbing structure, Figure 3It can be seen that under the normal incidence of any polarized wave, the structure has two resonance points, is insensitive to the polarization mode, and maintains excellent wave absorbing performance.

[0052] Figure 4 is the reflection coefficient S obtained when the TE wave enters the electromagnetic model at different angles. 11 The simulation results show that the incident angle They are 、 、 and .from Figure 4 It can be seen that under TE polarization, when the incident angle and When the incident angle is When , the bandwidth of the absorbing structure decreases and the absorbing performance deteriorates.

[0053] Figure 5 is the simulation result of the reflection coefficient when the TM wave enters the electromagnetic model at different angles, where the incident angle is They are 、 、 and .from Figure 5 It can be seen that under TM polarization, when the incident angle 、 and When the incident angle is When , the bandwidth of the absorbing structure decreases and the absorbing performance decreases. Figure 4 compared to, Figure 5 The reflection coefficient in the image is kept more consistent.

[0054] Figure 6 This is the simulation result of the frequency-dependent absorption rate A obtained when the TE wave and TM wave are incident on the electromagnetic model. Figure 6 It can be seen that in both TE and TM polarization modes, the absorption rate from 372.2 MHz to 1377.4 MHz is 90 As described above, the wave absorbing structure ensures good wave absorbing performance.

[0055] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0056] The one or more embodiments of this application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application should be included in the scope of protection of this application.

Claims

1. A P-band low-cost, high-bandwidth, lightweight, flexible absorbing structure based on metamaterials, characterized by: The invention comprises a plurality of periodically arranged basic units, wherein the basic units comprise a reflective plate and a dielectric plate connected in a stacked manner, the dielectric plate being provided with a functional unit, the functional unit comprising an outer closed-loop patch and an inner closed-loop patch located inside the outer closed-loop patch, the outer closed-loop patch having at least two protruding corners, a concave area being provided between the protruding corners, a connecting patch being connected between the concave area and the inner closed-loop patch, a middle closed-loop patch being further provided inside the protruding corners, and energy-consuming parts being provided on the outer closed-loop patch and / or the connecting patch.

2. The wave absorbing structure according to claim 1, wherein: The reflective plate is a metal plate, the functional unit is made of metal material, and the energy dissipation component is a resistor.

3. The wave absorbing structure according to claim 1, wherein: The end of the connecting patch is located inside the inner closed-loop patch.

4. The wave absorbing structure according to claim 3, wherein: The end of the connecting patch is provided with an end-sealing patch.

5. The wave absorbing structure according to any one of claims 1 to 4, wherein: The protruding angles are evenly distributed with the center point of the functional unit as the center, and the center of the inner closed-loop patch is the center point of the functional unit.

6. The wave absorbing structure according to any one of claims 1 to 4, wherein: The protruding corner is in an arc shape, the middle closed-loop patch is in a circle, and the inner closed-loop patch is in a rectangle.

7. The wave absorbing structure according to claim 6, wherein: The protruding corner is in the shape of a 3 / 4 circular ring, and the inner closed-loop patch is in the shape of a square.

8. The wave absorbing structure according to any one of claims 1 to 4, wherein: The number of the protruding corners is four, the number of the middle closed-loop patches is four, and the number of the connecting patches is four.

9. The wave absorbing structure according to any one of claims 1 to 4, wherein: The energy consuming parts are evenly distributed around the center point of the functional unit.

10. The wave absorbing structure according to any one of claims 1 to 4, characterized in that: The middle closed-loop patch is not connected to the outer closed-loop patch or the inner closed-loop patch.

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