Superstructure with adjustable wave-absorbing frequency band

Abstract

The invention relates to the technical field of electromagnetic wave-absorbing structures, and discloses a wave-absorbing frequency band adjustable superstructure, which sequentially comprises an impedance type metasurface layer upper layer, an impedance type metasurface layer substrate, an impedance type metasurface layer lower layer, a gap layer and a metal layer from top to bottom, and is characterized in that the impedance type metasurface layer upper layer is connected with the impedance type metasurface layer lower layer through a metal column; each of the impedance type metasurface layer upper layer and the impedance type metasurface layer lower layer comprises a plurality of broken-line-shaped resistance wire units, and the broken-line-shaped resistance wire units have the same surface resistance. According to the superstructure with the adjustable wave-absorbing frequency band, adjustment of different wave-absorbing frequency bands is achieved by changing the thickness of the gap layer and changing the position of the strongest resonance frequency point, the practicability of the wave-absorbing structure is greatly improved, and the superstructure has wide application prospects in the fields of microwave communication, RCS reduction, electromagnetic compatibility design, electromagnetic protection and the like.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic wave absorbing structures, and in particular to a wave absorbing frequency band adjustable superstructure. Background Art

[0002] The rapid development of information technology has led to an increase in the number of electronic devices capable of communication. The electromagnetic radiation generated by them has brought potential damage to human health and posed a great challenge to the safety and stability of sensitive electronic devices. In order to eliminate and reduce the impact of electromagnetic radiation, the more effective technical solution at this stage is to use electromagnetic wave absorption technology, which converts the radiated electromagnetic energy into heat energy, thereby dissipating the electromagnetic energy and achieving the purpose of electromagnetic protection.

[0003] Common electromagnetic wave absorption technologies are mainly based on two aspects: wave absorbing materials and wave absorbing structures. Wave absorbing materials have the disadvantages of narrow wave absorption band, limited absorption performance and high density; traditional wave absorbing structures represented by Salisbury screen and Jaumann have single (Salisbury) or multiple (Jaumann) resistance layers. The absorption band of Salisbury screen is relatively narrow, and Jaumann increases the thickness of the wave absorbing structure while expanding the bandwidth. At present, wave absorbing structures represented by metasurfaces are widely studied due to their high designability, broadband wave absorbing performance and thin thickness. However, most of the metasurface wave absorbing structures belong to wave absorbing structures with non-modulatable wave absorbing performance, that is, after design and processing, they can only achieve fixed intensity wave absorbing performance in a fixed frequency band range. With the increasingly complex and diversified electromagnetic environment, this type of wave absorbing structure has gradually failed to meet the current use needs. At this stage, it is necessary to design a wave absorbing technology with switchable wave absorbing performance in a multi-band range to solve the current problem. Summary of the invention

[0004] The purpose of the present invention is to provide a superstructure with adjustable absorbing frequency band, which can adjust different absorbing frequency bands by changing the thickness of the gap layer and the position of the strongest resonant frequency point, thereby greatly improving the practicality of the absorbing structure.

[0005] To achieve the above-mentioned purpose, the present invention provides a wave-absorbing frequency-band adjustable superstructure, comprising an impedance-type supersurface layer upper layer, an impedance-type supersurface layer substrate, an impedance-type supersurface layer lower layer, a gap layer, and a metal layer. The impedance-type supersurface layer upper layer is arranged at the topmost layer, the lower layer of the impedance-type supersurface layer upper layer is the impedance-type supersurface layer substrate, the lower layer of the impedance-type supersurface layer substrate is the impedance-type supersurface layer lower layer, the impedance-type supersurface layer upper layer is connected to the impedance-type supersurface layer lower layer through a metal column, the lower layer of the impedance-type supersurface layer lower layer is the gap layer, the lower layer of the gap layer is the metal layer, the impedance-type supersurface layer upper layer and the impedance-type supersurface layer lower layer both include a plurality of zigzag resistance line units, and the zigzag resistance line units all have the same surface resistance.

[0006] Preferably, the upper layer of the impedance type super surface layer and the lower layer of the impedance type super surface layer are both squares, and the upper layer of the impedance type super surface layer and the lower layer of the impedance type super surface layer are respectively divided into four parts by the diagonal of the square, and each part is rotated 90° symmetrically, and the four parts of the upper layer of the impedance type super surface layer are respectively connected to the four parts of the lower layer of the impedance type super surface layer through metal columns close to the side of the square diagonal.

[0007] Preferably, the width of the zigzag resistance line unit is 0.4-1.1 mm, the spacing between adjacent zigzag lines on the zigzag resistance line unit is 0.4-1.1 mm; and the square resistance constituting the zigzag resistance line unit is 80-200Ω / sq.

[0008] Preferably, the functional layers of the upper layer of the impedance-type supersurface layer and the lower layer of the impedance-type supersurface layer are made by inkjet printing, screen printing, magnetron sputtering, or ITO film technology.

[0009] Preferably, the impedance type super surface layer substrate is a FR4 dielectric board or a PI film, and the thickness of the impedance type super surface layer substrate is 0.1 to 3.0 mm.

[0010] Preferably, the diameter of the metal column is 0.4-1.1 mm, and the height is 0.1-30 mm.

[0011] Preferably, the gap layer is air or a lossy elastic medium, and the thickness of the gap layer is regulated by a mechanical regulating device.

[0012] Therefore, the present invention adopts the above-mentioned wave-absorbing frequency-band adjustable superstructure, which has the following beneficial effects:

[0013] (1) The wave-absorbing frequency-band adjustable superstructure of the present invention comprises five layers: an upper layer of an impedance-type supersurface layer, a substrate of an impedance-type supersurface layer, a lower layer of an impedance-type supersurface layer, a gap layer, and a metal layer. The gap layer, which is a wave-absorbing functional layer, has only one layer, and the overall structure is simple.

[0014] (2) The tunable absorbing frequency band superstructure of the present invention is composed of a five-layer structure and has polarization stability. By changing the thickness of the gap layer, the position of the strongest resonant frequency point can be changed to achieve the adjustment of different absorbing frequency bands, and adjustable absorbing can be achieved in the range of 1-100 GHz.

[0015] (3) The impedance-type super-surface layer of the present invention can be used in the impedance matching design of multi-layer structures due to its uniform broadband loss characteristics.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. 4 is a schematic cross-sectional view of a superstructure with adjustable absorbing frequency band according to an embodiment of the present invention.

[0018] Figure 2 Schematic diagram of the structure of the tunable absorbing frequency band superstructure unit according to an embodiment of the present invention.

[0019] Figure 3 It is a front schematic diagram of the impedance-type supersurface layer structure unit according to an embodiment of the present invention.

[0020] Figure 4 It is a schematic diagram of the back side of the impedance-type super-surface layer structure unit according to an embodiment of the present invention.

[0021] Figure 5 It is the reflection coefficient when the gap layer thickness h=0.3mm and 0.1mm in the embodiment of the present invention.

[0022] Figure 6 It is the absorption rate when the gap layer thickness h=0.3mm and 0.1mm in the embodiment of the present invention.

[0023] Figure 7 : is the reflection coefficient when the gap layer thickness h=0.7 mm, 1.0 mm, 1.7 mm, and 3.0 mm in the embodiment of the present invention.

[0024] Figure 8 It is the absorption rate when the gap layer thickness h=0.7mm, 1.0mm, 1.7mm, and 3.0mm in the embodiment of the present invention.

[0025] Fig. 9 It is the reflection coefficient when the gap layer thickness h=5.0 mm in the embodiment of the present invention.

[0026] Fig.10 It is the absorption rate when the gap layer thickness h=5.0 mm in the embodiment of the present invention.

[0027] Fig.11 It is the reflection coefficient when the gap layer thickness h=9.0 mm in the embodiment of the present invention.

[0028] Fig.12 It is the absorption rate when the gap layer thickness h=9.0 mm in the embodiment of the present invention.

[0029] Fig.13 It is the reflection coefficient when the gap layer thickness h=12.0 mm in the embodiment of the present invention.

[0030] Fig.14 It is the absorption rate when the gap layer thickness h=12.0 mm in the embodiment of the present invention.

[0031] Fig.15 : is the reflection coefficient at different polarization angles when the gap layer thickness h=0.1 mm in the embodiment of the present invention.

[0032] Reference numerals

[0033] 1. Impedance type super surface layer upper layer; 2. Impedance type super surface layer substrate; 3. Impedance type super surface layer lower layer; 4. Gap layer; 5. Metal layer; 6. Metal column. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects. The terms "set", "install" and "connect" 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 or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] Example

[0037] like Figure 1As shown, the wave absorbing frequency band adjustable superstructure of the present invention comprises, from top to bottom, an impedance type super surface layer upper layer 1, an impedance type super surface layer substrate 2, an impedance type super surface layer lower layer 3, an adjustable gap layer 4, and a metal layer 5. The impedance type super surface layer upper layer 1 is arranged at the topmost layer, the lower layer of the impedance type super surface layer upper layer 1 is the impedance type super surface layer substrate 2, and the lower layer of the impedance type super surface layer substrate 2 is the impedance type super surface layer lower layer 3. The impedance type super surface layer substrate 2 is one of the common PCB plate making processes such as FR4 dielectric board and PI film, and has a thickness of 0.1 to 3.0 mm.

[0038] The schematic diagram of the unit structure of the wave absorbing frequency band adjustable superstructure of the present invention is as follows Figure 2 As shown, the upper layer 1 of the impedance type super surface layer is connected to the lower layer 3 of the impedance type super surface layer through a metal column 6. The metal column 6 can be any metal, and the diameter of the metal column 6 is 0.4-1.1 mm and the height is 0.1-30 mm.

[0039] The structural units of the upper layer 1 of the impedance type super surface layer and the lower layer 3 of the impedance type super surface layer are shown in FIG. Figure 3 , Figure 4 , the impedance type super surface layer upper layer 1 and the impedance type super surface layer lower layer 3 both include a number of zigzag resistance line units, and the zigzag resistance line units all have the same surface resistance. The impedance type super surface layer upper layer and the impedance type super surface layer lower layer 3 are both squares, and the impedance type super surface layer upper layer 1 and the impedance type super surface layer lower layer 3 are respectively divided into four parts by the square diagonal, and each part is symmetrical by rotating 90°. The four parts of the impedance type super surface layer upper layer 1 are respectively connected to the four parts of the impedance type super surface layer lower layer 3 by the metal pillars 6 close to the side of the square diagonal. The width of the zigzag resistance line unit in the impedance type super surface layer upper layer 1 and the impedance type super surface layer lower layer 3 is 0.4-1.1mm, the spacing between adjacent zigzag lines of the zigzag resistance line unit is 0.4-1.1mm, and the number of bending times of the zigzag resistance line unit is greater than three times. The square resistance of the zigzag resistance line unit is 80-200Ω / sq. The impedance type super surface layer upper layer 1 and the impedance type super surface layer lower layer 3 are realized by inkjet printing, screen printing, magnetron sputtering, ITO film and other processes. In this embodiment, inkjet printing is used for preparation. The impedance type super surface layer itself has good broadband loss characteristics within the ultra-wideband range, and is close to air impedance within the ultra-wideband range. This is one of the keys for the structure of the present invention to achieve ultra-wideband adjustable wave absorption. The impedance type super surface layer upper layer 1 and the impedance type super surface layer lower layer 3, which are divided into two layers, are connected by metal columns 6, and the double-layer design realizes unit miniaturization.

[0040] The lower layer of the impedance type super surface layer lower layer 3 is the gap layer 4. The adjustable gap layer 4 can be air or other lossy elastic medium, and the thickness of the gap layer 4 is regulated according to the mechanical control device. By changing the thickness of the gap layer 4, the position of the strongest resonant frequency point is changed, and the adjustment of different absorbing frequency bands is achieved, which is one of the keys to achieve ultra-wideband adjustable absorbing in the structure of the present invention.

[0041] The lower layer of the gap layer 4 is a metal layer 5. The metal selected for the metal layer 5 is copper, and the thickness is 0.035 mm. The metal layer 5 only serves as an electromagnetic wave reflector to achieve a quarter-wave loss mechanism.

[0042] The tunable absorbing band superstructure of this embodiment is analyzed using simulation software to explain the working characteristics of the structure. Electromagnetic simulation is performed on the absorbing structure of this embodiment in the simulation software. Figure 5 As shown in FIG. 1 , when the thickness of the gap layer 4 is h = 0.3 mm and 0.1 mm, the frequency bands where the reflection coefficient is lower than -10 dB are 41.6 GHz to 68.9 GHz and 66.6 GHz to 100.0 GHz, respectively. Figure 6 The frequency bands where the absorbance is greater than 90% are shown to be consistent.

[0043] like Figure 7 As shown, when the thickness of the gap layer 4 is h = 0.7mm, 1.0mm, 1.7mm, and 3.0mm, the frequency bands where the reflection coefficient is lower than -10dB are 24.8GHz to 43.5GHz, 22.8GHz to 38.3GHz, 16.6GHz to 31.2GHz, and 9.7GHz to 18.7GHz, respectively. Figure 8 The frequency bands where the absorbance is greater than 90% are shown to be consistent.

[0044] like Fig. 9 As shown in FIG. 1 , when the thickness of the gap layer 4 is h=5.0 mm, the frequency bands where the reflection coefficient is lower than -10 dB are 6.1 GHz to 13.8 GHz and 33.4 GHz to 38.3 GHz respectively. Fig.10 The frequency bands where the absorbance is greater than 90% are shown to be consistent.

[0045] like Fig.11 As shown in FIG. 1 , when the thickness of the gap layer 4 is h = 9.0 mm, the frequency bands where the reflection coefficient is lower than -10 dB are 4.1 GHz to 8.0 GHz, 18.8 GHz to 24.1 GHz, and 34.8 GHz to 38.5 GHz. Fig.12 The frequency bands where the absorbance is greater than 90% are shown to be consistent.

[0046] like Fig.13As shown in FIG. 1 , when the thickness of the gap layer 4 is h=12.0 mm, the frequency bands where the reflection coefficient is lower than -10 dB are 3.5 GHz to 5.4 GHz, 14.6 GHz to 17.0 GHz, 38.5 GHz to 40.7 GHz, and 26.5 GHz to 29.2 GHz. Fig.14 The frequency bands where the absorbance is greater than 90% are shown to be consistent.

[0047] like Fig.15 As shown, in the present invention, when the thickness of the gap layer 4 is h=0.1 mm, the reflection coefficient at different polarization angles remains stable as the polarization angle changes, showing excellent polarization stability.

[0048] Therefore, the present invention adopts the above-mentioned superstructure with adjustable absorbing frequency band, and realizes the adjustment of different absorbing frequency bands by changing the thickness of the gap layer and the position of the strongest resonant frequency point, which greatly improves the practicality of the absorbing structure and has broad application prospects in microwave communication, RCS reduction, electromagnetic compatibility design, electromagnetic protection and other fields.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A microwave absorption band adjustable superstructure, characterized in that: The invention comprises an impedance type super surface layer upper layer, an impedance type super surface layer substrate, an impedance type super surface layer lower layer, a gap layer and a metal layer. The impedance type super surface layer upper layer is arranged at the topmost layer. The lower layer of the impedance type super surface layer upper layer is the impedance type super surface layer substrate. The lower layer of the impedance type super surface layer substrate is the impedance type super surface layer lower layer. The impedance type super surface layer upper layer is connected with the impedance type super surface layer lower layer through a metal column. The lower layer of the impedance type super surface layer lower layer is the gap layer. The lower layer of the gap layer is the metal layer. The impedance type super surface layer upper layer and the impedance type super surface layer lower layer both comprise a number of zigzag resistance line units. The zigzag resistance line units all have the same surface resistance.

2. The microwave absorbing band adjustable superstructure according to claim 1, characterized in that: The upper layer of the impedance-type supersurface layer and the lower layer of the impedance-type supersurface layer are both squares. The upper layer of the impedance-type supersurface layer and the lower layer of the impedance-type supersurface layer are respectively divided into four parts by the diagonals of the squares. Each part is rotated 90° symmetrically. The four parts of the upper layer of the impedance-type supersurface layer are respectively connected to the four parts of the lower layer of the impedance-type supersurface layer by metal columns close to the side of the diagonals of the squares.

3. The microwave absorbing band adjustable superstructure according to claim 1, characterized in that: The width of the zigzag resistance line unit is 0.4-1.1 mm, the spacing between adjacent zigzag lines on the zigzag resistance line unit is 0.4-1.1 mm; the square resistance constituting the zigzag resistance line unit is 80-200Ω / sq.

4. The microwave absorbing band adjustable superstructure according to claim 1, characterized in that: The upper layer of the impedance-type super surface layer and the upper layer of the impedance-type super surface layer are made by inkjet printing, screen printing, magnetron sputtering, and ITO film technology.

5. The microwave absorbing band adjustable superstructure according to claim 1, characterized in that: The impedance type super surface layer substrate is a FR4 dielectric board or a PI film, and the thickness of the impedance type super surface layer substrate is 0.1 to 3.0 mm.

6. The microwave absorbing band adjustable superstructure according to claim 1, characterized in that: The diameter of the metal column is 0.4 to 1.1 mm, and the height is 0.1 to 30 mm.

7. The microwave absorbing band adjustable superstructure according to claim 1, characterized in that: The gap layer is air or a lossy elastic medium, and the thickness of the gap layer is regulated by a mechanical regulating device.

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