Electromagnetic wave absorbing unit and electromagnetic wave absorbing structure

Abstract

The present invention discloses an electromagnetic wave absorbing unit and an electromagnetic wave absorbing structure. The electromagnetic wave absorbing unit includes a first dielectric layer and a first metal unit structure and a second metal unit structure respectively arranged on the upper and lower end surfaces of the first dielectric layer. The first metal unit structure includes an upper metal arm, a lower metal arm, a left coupling line, and a right coupling line, which are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer. The second metal unit structure includes a left metal arm, a right metal arm, an upper coupling line, and a lower coupling line, which are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer. Through the coordination between the metal arms and the coupling lines, strong coupling is formed between adjacent metal arms, and the impedance and resistance between the metal arms are well matched, thereby broadening the absorption bandwidth of the electromagnetic wave absorbing unit and the electromagnetic wave absorbing structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave absorption, and in particular relates to an electromagnetic wave absorbing unit and an electromagnetic wave absorbing structure. Background Art

[0002] Electromagnetic absorbing structures effectively absorb and attenuate incident electromagnetic waves, dissipating their energy as heat. These structures can be used to enhance the stealth of military equipment, such as fighter jets and ships, by reducing their radar scattering area and lowering their probability of detection. They can also be used in various electronic devices to reduce electromagnetic radiation, ensuring they meet electromagnetic compatibility requirements, or to absorb and suppress stray signals emitted by electronic devices to prevent interference with other equipment. Furthermore, electromagnetic absorbing structures can be used in microwave anechoic chambers to reduce electromagnetic wave reflection from floors and walls.

[0003] Metamaterial-based electromagnetic absorption structures can be equivalent to electric and magnetic resonance structures, and therefore can usually only achieve point-frequency or multi-frequency electromagnetic wave absorption at the resonance point, and their absorption bandwidth is also relatively narrow. Patent document 201710585397.9 discloses a metamaterial three-band absorption structure based on electromagnetic resonance. This electromagnetic absorption structure can only operate at 3.39 GHz, 4.94 GHz, and 9.91 GHz. The Salisbury Screen absorption structure is also a single-frequency absorption structure that only works when the overall thickness of the structure is equal to one-quarter of the operating wavelength, and it cannot achieve broadband absorption. Summary of the Invention

[0004] The purpose of the present invention is to provide an electromagnetic wave absorbing unit and an electromagnetic wave absorbing structure to solve the problem that the existing electromagnetic wave absorbing structure can only absorb waves at a single frequency point and has a narrow absorption bandwidth, thereby achieving the purpose of expanding the absorption bandwidth.

[0005] The present invention is achieved through the following technical solutions:

[0006] An electromagnetic wave absorbing unit includes a first dielectric layer and a first metal unit structure and a second metal unit structure respectively arranged on the upper and lower end surfaces of the first dielectric layer; the first metal unit structure includes an upper metal arm, a lower metal arm, a left coupling line and a right coupling line, the upper metal arm, the right coupling line, the lower metal arm and the left coupling line are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer, the upper metal arm and the lower metal arm are arranged opposite to each other and located on the same straight line, the left coupling line and the right coupling line are arranged opposite to each other and located on the same straight line, a first resistor is arranged between the upper metal arm and the lower metal arm, and the first resistor is connected to the upper metal arm and the lower metal arm respectively; the second metal unit structure includes The left metal arm, the right metal arm, the upper coupling line, and the lower coupling line are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer. The left metal arm and the right metal arm are arranged opposite to each other and are located on the same straight line. The upper coupling line and the lower coupling line are arranged opposite to each other and are located on the same straight line. A second resistor is provided between the left metal arm and the right metal arm, and the second resistor is connected to the left metal arm and the right metal arm respectively. On the first dielectric layer, the upper metal arm, the right metal arm, the lower metal arm, and the left metal arm are arranged in an array along the horizontal and vertical directions. The upper coupling line, the right coupling line, the lower coupling line, and the left coupling line are arranged in an array along the horizontal and vertical directions.

[0007] Furthermore, the upper coupling line, the right coupling line, the lower coupling line, and the left coupling line are located at positions corresponding to the upper metal arm, the right metal arm, the lower metal arm, and the left metal arm, respectively.

[0008] Furthermore, the upper metal arm and the upper coupling line, the right metal arm and the right coupling line, the lower metal arm and the lower coupling line, and the left metal arm and the left coupling line partially overlap at their ends.

[0009] Furthermore, the upper metal arm, the lower metal arm, the left metal arm, and the right metal arm are long metal strips, and one end thereof connected to the first resistor and the second resistor is configured as a cut-angle structure.

[0010] Furthermore, the upper coupling line, the lower coupling line, the left coupling line and the right coupling line are square metal plates.

[0011] Furthermore, the lengths of the upper metal arm, the lower metal arm, the left metal arm, and the right metal arm are one quarter of the wavelength corresponding to the center frequency.

[0012] On the other hand, the present invention further provides an electromagnetic wave absorbing structure, comprising the electromagnetic wave absorbing unit described above.

[0013] Furthermore, the electromagnetic absorbing structure includes a second dielectric layer and a metal backplate, the battery absorbing unit is arranged on the second dielectric layer, and the second dielectric layer is arranged on the metal backplate.

[0014] Furthermore, the second medium layer is a foam material layer.

[0015] Furthermore, the thickness of the second dielectric layer is one quarter of the wavelength corresponding to the center frequency.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] The electromagnetic absorbing unit and electromagnetic absorbing structure use two metal unit structures, and by improving the structure of the metal unit structure and the relative arrangement structure between the two metal unit structures, an array of metal arms and an array of coupling line structures are formed. When electromagnetic waves are irradiated on the absorbing unit, the electromagnetic waves are coupled to each metal arm, and energy is coupled through the metal arms and consumed in the resistor, thereby achieving full absorption of the electromagnetic waves. At the same time, through the cooperation between the metal arms and the coupling lines, strong coupling can be formed between each adjacent metal arm, so that the impedance and resistance between the metal arms are well matched, thereby broadening the absorbing bandwidth of the electromagnetic absorbing unit and the electromagnetic absorbing structure, and can be widely used in various scenarios requiring electromagnetic absorption and shielding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the unit structure of an electromagnetic absorbing unit in one embodiment of the present invention.

[0020] Figure 2 Schematic diagram of the structure of the first metal unit in the electromagnetic absorbing unit of the present invention.

[0021] Figure 3 Schematic diagram of the structure of the second metal unit in the electromagnetic absorbing unit of the present invention.

[0022] Figure 4 This is a schematic cross-sectional view of an embodiment of the electromagnetic wave absorbing structure of the present invention.

[0023] Figure 5 This is a schematic diagram of the three-dimensional structure of an embodiment of the electromagnetic absorbing structure of the present invention.

[0024] Figure 6 This is a simulation curve of the electromagnetic wave absorption rate of the electromagnetic wave absorbing structure of the present invention at different frequencies.

[0025] Among them: 1-first metal unit structure, 2-first dielectric layer, 3-second metal unit structure, 4-second dielectric layer, 5-metal backplate, 6-upper metal arm, 7-lower metal arm, 8-left metal arm, 9-right metal arm, 10-first resistor, 11-second resistor, 16-upper coupling line, 17-lower coupling line, 18-left coupling line, 19-right coupling line. DETAILED DESCRIPTION

[0026] 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 only part of the embodiments of the present invention, not all of the embodiments.

[0027] In one embodiment, if Figure 1 As shown, an electromagnetic absorbing unit includes a first dielectric layer 2 and a first metal unit structure 1 and a second metal unit structure 3 respectively arranged on the upper and lower end surfaces of the first dielectric layer 2.

[0028] The first metal unit structure 1 includes an upper metal arm 6, a lower metal arm 7, a left coupling line 18 and a right coupling line 19. The upper metal arm 6, the right coupling line 19, the lower metal arm 7 and the left coupling line 18 are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer; Figure 2 Taking the structure in FIG as an example, the horizontal and vertical array arrangement here means: on the end surface of the first dielectric layer 2, the upper metal arm 6 and the lower metal arm 7 are arranged in the vertical direction, and the left coupling line 18 and the right coupling line 19 are arranged in the horizontal direction. The upper metal arm 6, the right coupling line 19, the lower metal arm 7, and the left coupling line 18 are arranged in a regular clockwise arrangement to form an array arrangement structure. In other words, the upper metal arm 6 and the lower metal arm 7 are arranged opposite each other and on the same straight line, and the left coupling line 18 and the right coupling line 19 are arranged opposite each other and on the same straight line. The axes of the upper metal arm 6, the right coupling line 19, the lower metal arm 7, and the left coupling line 18 form a 90° angle.

[0029] A first resistor 10 is provided between the upper metal arm 6 and the lower metal arm 7 , and is connected to the upper metal arm 6 and the lower metal arm 7 respectively. Generally, the first resistor 10 can be connected to the upper metal arm 6 and the lower metal arm 7 by welding.

[0030] The second metal unit structure includes a left metal arm 8, an upper coupling line 16, a right metal arm 9 and a lower coupling line 17. The left metal arm 8, the upper coupling line 16, the right metal arm 9 and the lower coupling line 17 are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer. Figure 3Taking the structural form in the example, the horizontal and vertical array arrangement here means: on the other end surface of the first dielectric layer, along the clockwise direction, the left metal arm 8 and the right metal arm 9 are arranged horizontally, and the upper coupling line 16 and the lower coupling line 17 are arranged vertically. The left metal arm 8, the upper coupling line 16, the right metal arm 9, and the lower coupling line 17 are arranged in a regular pattern along the clockwise direction to form an array arrangement structure. In other words, the left metal arm 8 and the right metal arm 9 are arranged opposite each other and on the same straight line, the upper coupling line 16 and the lower coupling line 17 are arranged opposite each other and on the same straight line, and the axes of the left metal arm 8, the upper coupling line 16, the right metal arm 9, and the lower coupling line 17 form a 90° angle.

[0031] A second resistor 11 is provided between the left metal arm 8 and the right metal arm 9 , and the second resistor 11 is connected to the left metal arm 8 and the right metal arm 9 respectively; generally, the second resistor 11 and the left metal arm 8 and the right metal arm 9 can be connected by welding.

[0032] As a preferred structure, the lengths of the upper metal arm 6, the lower metal arm 7, the left metal arm 8, and the right metal arm 9 are approximately one-quarter of the wavelength corresponding to the center frequency. The center frequency here refers to the average of the highest and lowest frequencies in the operating frequency band.

[0033] In the electromagnetic wave absorbing unit, the relative structure between the first metal unit and the second metal unit is set so that the following structure is formed between the first metal unit and the second metal unit:

[0034] On the first dielectric layer 2, the upper metal arm 6, the right metal arm 9, the lower metal arm 7 and the left metal arm 8 are arranged in an array along the horizontal and vertical directions. Figure 1 Taking the structural form in the example, the arrangement of the upper metal arm 6 and the lower metal arm 7 in the horizontal and vertical directions means that the upper metal arm 6 and the lower metal arm 7 are arranged in the vertical direction, the right metal arm 9 and the left metal arm 8 are arranged in the horizontal direction, and the upper metal arm 6, the right metal arm 9, the lower metal arm 7 and the left metal arm 8 are arranged at a 90° angle to each other, forming an array distribution structure in the clockwise direction. At the same time, the upper coupling line, the right coupling line, the lower coupling line and the left coupling line are arranged in an array in the horizontal and vertical directions. Similarly, Figure 1 Taking the structure in as an example, the left coupling line 18 and the right coupling line 19 are arranged in the horizontal direction, the upper coupling line 16 and the lower coupling line 17 are arranged in the vertical direction, and the axes of the left coupling line 18, the upper coupling line 16, the right coupling line 19 and the lower coupling line 17 are respectively at an angle of 90°, forming an array distribution structure in the clockwise direction.

[0035] In one embodiment, the upper coupling line 16, the right coupling line 19, the lower coupling line 17, and the left coupling line 18 are respectively arranged at the ends of the upper metal arm 6, the right metal arm 9, the lower metal arm 7, and the left metal arm 8 away from the resistor; between the upper metal arm 6 and the upper coupling line 16, between the right metal arm 9 and the right coupling line 19, between the lower metal arm 7 and the lower coupling line 17, and between the left metal arm 8 and the left coupling line 18, each coupling line and each corresponding metal arm partially overlaps at the end of the metal arm away from the resistor. This structural form can be understood as enabling the electromagnetic absorbing unit to have a better absorbing effect.

[0036] like Figure 2 and Figure 3 As shown, the upper metal arm 6, the lower metal arm 7, the left metal arm 8, and the right metal arm 9 are long metal strips, generally preferably made of copper; the upper metal arm 6 and the lower metal arm 7 are configured as a cut-angle structure at one end connected to the first resistor 10, and the left metal arm 8 and the right metal arm 9 are also configured as a cut-angle structure at one end connected to the second resistor 11. The setting of the cut-angle structure can prevent the end portions of each metal arm from overlapping each other when the array is set up, and can match each metal arm with the corresponding resistor at the connection position, so that the electromagnetic absorbing unit can achieve a better absorbing effect.

[0037] Based on the functions of the upper coupling line 16, the lower coupling line 17, the left coupling line 18, and the right coupling line 19, it is understandable that the upper coupling line 16, the lower coupling line 17, the left coupling line 18, and the right coupling line 19 are made of metal, preferably copper. In this embodiment, the upper coupling line 16, the lower coupling line 17, the left coupling line 18, and the right coupling line 19 are preferably square metal plates.

[0038] In one embodiment, the first dielectric layer 2 may use a Rogers 5880 dielectric substrate, which is a polytetrafluoroethylene glass fiber reinforced material with a stable dielectric constant. Copper plates are usually attached to the upper and lower surfaces of the Rogers 5880 dielectric substrate. The copper plates on both sides are corroded to obtain a first metal unit structure and a second metal unit structure, thereby preparing the electromagnetic absorbing unit in this embodiment. The thickness of the copper plate is generally 0.018 mm.

[0039] In one embodiment, an electromagnetic wave absorbing structure adopts the electromagnetic wave absorbing unit in the above embodiment.

[0040] In one embodiment, referring to Figure 4 and Figure 5 ,in, Figure 5It is an overall three-dimensional structure of the absorbing structure; the electromagnetic absorbing structure includes a second dielectric layer 4 and a metal backplate 5, the electromagnetic absorbing unit is arranged on the second dielectric layer 4, and the second dielectric layer 4 is arranged on the metal backplate 5. It can be understood that the electromagnetic absorbing structure is, from top to bottom, a first metal unit structure 1, a first dielectric layer 2, a second metal unit structure 3, a second dielectric layer 4, and a metal backplate 5.

[0041] The second dielectric layer 4 is a foam material layer with a thickness of 15 mm, and its thickness is one quarter of the wavelength corresponding to the center frequency.

[0042] When electromagnetic waves hit the electromagnetic absorbing structure, they are converted into guided waves and coupled to the metal arms. The energy is coupled through the metal arms, transferred to the resistors, and then converted into heat energy and dissipated, thereby achieving the absorption and consumption of electromagnetic waves. Through the coupling lines and metal arms set up in the array, and the coordination between the metal arms and the coupling lines, strong coupling can be formed between the adjacent metal arms, so that the impedance and resistance between the metal arms are well matched, thereby achieving the effect of broadband absorption.

[0043] like Figure 6 As shown in FIG. 1 , a simulation curve of the absorption rate of electromagnetic waves of different frequencies using the electromagnetic absorbing structure in the above embodiment is shown. From the experimental data, it can be seen that when the electromagnetic wave is irradiated by the electromagnetic absorbing structure, the electromagnetic absorbing structure has an absorption rate greater than 90% for electromagnetic waves from 1.74 GHz to 8.24 GHz, achieving broadband absorption.

[0044] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. used to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0045] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of the present invention does not necessarily imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical" and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0046] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific contexts.

[0047] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. An electromagnetic absorbing unit, characterized in that: The invention comprises a first dielectric layer (2) and a first metal unit structure and a second metal unit structure respectively arranged on the upper and lower end surfaces of the first dielectric layer (2); the first metal unit structure comprises an upper metal arm (6), a lower metal arm (7), a left coupling line (18) and a right coupling line (19); the upper metal arm (6), the right coupling line (19), the lower metal arm (7) and the left coupling line (18) are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer (2); the upper metal arm (6) and the lower metal arm (7) are arranged opposite to each other and are located on the same straight line; the left coupling line (18) and the right coupling line (19) are arranged opposite to each other and are located on the same straight line; a first resistor (10) is arranged between the upper metal arm (6) and the lower metal arm (7); the first resistor (10) is connected to the upper metal arm (6) and the lower metal arm (7) respectively; the second metal unit structure comprises a left metal arm (8), a right metal arm (9), An upper coupling line (16) and a lower coupling line (17), the left metal arm (8), the upper coupling line (16), the right metal arm (9) and the lower coupling line (17) are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer (2), the left metal arm (8) and the right metal arm (9) are arranged opposite to each other and are located on the same straight line, the upper coupling line (16) and the lower coupling line (17) are arranged opposite to each other and are located on the same straight line, a second resistor (11) is arranged between the left metal arm (8) and the right metal arm (9), and the second resistor (11) is connected to the left metal arm (8) and the right metal arm (9) respectively; on the first dielectric layer (2), the upper metal arm (6), the right metal arm (9), the lower metal arm (7) and the left metal arm (8) are arranged in an array along the horizontal and vertical directions, and the upper coupling line (16), the right coupling line (19), the lower coupling line (17) and the left coupling line (18) are arranged in an array along the horizontal and vertical directions.

2. The electromagnetic absorbing unit according to claim 1, wherein: The upper coupling line (16), the right coupling line (19), the lower coupling line (17), and the left coupling line (18) are respectively located at positions corresponding to the upper metal arm (6), the right metal arm (9), the lower metal arm (7), and the left metal arm (8).

3. The electromagnetic absorbing unit according to claim 2, wherein: Partial overlap is formed at the ends of the upper metal arm (6) and the upper coupling line (16), the right metal arm (9) and the right coupling line (19), the lower metal arm (7) and the lower coupling line (17), and the left metal arm (8) and the left coupling line (18).

4. The electromagnetic absorbing unit according to claim 1, wherein: The upper metal arm (6), the lower metal arm (7), the left metal arm (8), and the right metal arm (9) are long metal strips, and one end thereof connected to the first resistor (10) and the second resistor (11) is configured as a cut-angle structure.

5. The electromagnetic absorbing unit according to claim 1, wherein: The upper coupling line (16), the lower coupling line (17), the left coupling line (18) and the right coupling line (19) are square metal plates.

6. The electromagnetic absorbing unit according to claim 1, characterized in that: The lengths of the upper metal arm (6), the lower metal arm (7), the left metal arm (8), and the right metal arm (9) are one quarter of the wavelength corresponding to the center frequency.

7. An electromagnetic wave absorbing structure, characterized in that: The electromagnetic absorbing unit comprises the electromagnetic absorbing unit according to any one of claims 1 to 6.

8. The electromagnetic wave absorbing structure according to claim 7, characterized in that: It comprises a second dielectric layer (4) and a metal back plate (5), wherein the electromagnetic wave absorbing unit is arranged on the second dielectric layer (4), and the second dielectric layer (4) is arranged on the metal back plate (5).

9. The electromagnetic wave absorbing structure according to claim 8, characterized in that: The second medium layer (4) is a foam material layer.

10. The electromagnetic wave absorbing structure according to claim 8 or 9, characterized in that: The thickness of the second dielectric layer (4) is one quarter of the wavelength corresponding to the center frequency.

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