A reflection frequency band can be widely controlled reflection wave absorber

Abstract

The application discloses a reflection wave-absorbing body with a wide-range controllable reflection frequency band, which comprises a lossy layer, a first dielectric layer, an air layer, a non-lossy layer, a second dielectric layer and a ground layer arranged from top to bottom; the lossy layer is located on the upper surface of the first dielectric layer, the air layer is between the first dielectric layer and the non-lossy layer, the non-lossy layer is located on the upper surface of the second dielectric layer, and the ground layer is located on the lower surface of the second dielectric layer. The reflection frequency band of the application has a certain bandwidth, and the wide-range control of the reflection frequency band can be realized by controlling the length of a C groove in the lossy layer and the length of a Jerusalem cross structure in the non-lossy layer, so that the application flexibility is obviously improved.

Description

A reflective absorber with a wide range of adjustable reflection frequencies Technical Field

[0001] This invention relates to the field of electromagnetic materials technology, and in particular to a reflective absorber with a wide range of adjustable reflection frequency bands. Background Technology

[0002] Antennas are one of the main components of radar systems, used to receive or transmit electromagnetic waves. As a significant scattering source within the radar system, the stealth of radar antennas is crucial for the stealth of military equipment. Traditional antenna stealth methods typically involve frequency-selective radomes with special structural designs that allow electromagnetic waves to pass through the antenna's operating frequency band while reflecting incident electromagnetic waves away from the detection radar outside that band. This achieves electromagnetic stealth against monostatic radars. However, this method is insufficient for achieving electromagnetic stealth against bistatic radars operating outside their frequency band.

[0003] Integrated reflector-absorbing structures are a special type of artificial electromagnetic material that achieves wave absorption over a wide frequency range, while also possessing total internal reflection characteristics in frequency bands both outside and within the absorption band. Using this structure as the reflector surface of an antenna allows for electromagnetic stealth in both monostatic and bistatic modes outside the antenna's operating frequency band. However, current integrated reflector-absorbing structures may suffer from issues such as a fixed reflection frequency band or, while the reflection frequency band is adjustable, a very narrow bandwidth. Summary of the Invention

[0004] Purpose of the invention: The present invention provides a reflective absorber with a wide range of adjustable reflection frequency bands, the reflection frequency band having a certain bandwidth.

[0005] Technical solution: The present invention provides a reflective absorber with a wide range of adjustable reflection frequency bands, comprising, from top to bottom, a lossy layer, a first dielectric layer, an air layer, a lossless layer, a second dielectric layer, and a ground layer; the lossy layer is located on the upper surface of the first dielectric layer, the air layer is between the first dielectric layer and the lossless layer, the lossless layer is located on the upper surface of the second dielectric layer, and the ground layer is located on the lower surface of the second dielectric layer. The wide range of adjustable reflection frequency bands is achieved by controlling the length of the C-shaped groove in the lossy layer and the length of the Jerusalem cross structure in the lossless layer.

[0006] Furthermore, the lossy layer has a periodic structure. Each unit of the periodic structure includes four circular patches, transmission lines connecting the circular patches, C-shaped slots, four connecting patches, a square ring patch, and a resistor. A C-shaped slot is etched on each circular patch. By changing the length of the C-shaped slot, its resonant frequency is changed to achieve the control of the transmission frequency. A resistor is soldered in the middle of each side of the square ring patch. Each corner of the square ring patch is connected to a circular patch through a connecting patch.

[0007] Furthermore, the height of the first dielectric layer is h1=0.5mm, the thickness of the air layer is t=4.4mm, and the thickness of the second dielectric layer is h2=2.7mm.

[0008] Furthermore, the dielectric layer material has a relative permittivity of 2.65 and a loss tangent of 0.002.

[0009] Furthermore, the lossless layer is periodically arranged in Jerusalem cross structure. The resonant frequency of the Jerusalem cross structure is affected by its length. Therefore, by changing its length, the power frequency can be controlled, which can play a role in adjusting the phase of the reflected wave, so as to achieve a broadband and highly selectable reflection frequency band.

[0010] Furthermore, the total reflection coefficient of the reflective absorber has a modulus of less than -10dB in both the low-frequency and high-frequency bands, indicating that it is in a wave-absorbing state.

[0011] Furthermore, the reflection band refers to a wide frequency band with a reflection coefficient modulus greater than -3dB and a steeper transition band. The ability to control the reflection band over a wide range is achieved by simultaneously changing the length of the C-shaped groove etched on the circular patch in the lossy layer unit and the length of the Jerusalem cross unit in the lossless layer.

[0012] Furthermore, the absorption efficiency is expressed by the formula A = 1 - |Γ| 2 The calculation shows that |Γ| represents the magnitude of the reflection coefficient.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention has a certain bandwidth in the reflection frequency band, and the reflection frequency band can be adjusted over a wide range by controlling the length of the C-slot in the lossy layer and the length of the Jerusalem cross structure in the lossless layer, thus significantly improving the flexibility of its application. Attached Figure Description

[0014] Figure 1 is a schematic diagram of the structure of the present invention.

[0015] Figure 2 is a schematic diagram of the unit structure of the lossy layer in this invention.

[0016] Figure 3 is a schematic diagram of the unit structure of the lossless layer in this invention.

[0017] Figure 4 shows the simulation results of the adjustable reflection frequency band of the present invention.

[0018] Figure 5 shows the simulation results of the absorption effect of the present invention. Detailed Implementation

[0019] As shown in Figure 1, a reflective absorber with a wide range of adjustable reflection frequency bands includes, from top to bottom, a lossy layer 1, a first dielectric layer 2, an air layer 3, a lossless layer 4, a second dielectric layer 5, and a ground layer 6; the lossy layer 1 is located on the upper surface of the first dielectric layer 2, the air layer 3 is between the first dielectric layer 2 and the lossless layer 4, the lossless layer 4 is located on the upper surface of the second dielectric layer 5, and the ground layer 6 is located on the lower surface of the second dielectric layer 5.

[0020] The first dielectric layer has a height h1 = 0.5 mm, an air layer thickness t = 4.4 mm, and a second dielectric layer thickness h2 = 2.7 mm. The relative permittivity of the dielectric layer material is 2.65, and the loss tangent is 0.002.

[0021] The lossy layer 1 consists of a periodic array, and its unit structure is shown in Figure 2. In the figure, gray represents metal patches, and black represents resistors. Each unit contains four circular patches 101, four connecting patches 103, and one square ring patch 104. Each circular patch 101 has a C-shaped groove 102 etched in it. A resistor 105 is soldered to the middle of each side of the square ring patch 104. Each corner of the square ring patch 104 is connected by a connecting patch 103 and a circular patch 101. The structural dimensions in the figure are adjusted according to actual performance requirements. In this embodiment, the initial values ​​of the structural dimensions are: P = 16 mm, l 11 = 4mm, l 12 = 0.3 mm, w 11 = 0.5 mm, w 12 = 1 mm, w 13 = 0.3 mm, w 14 = 1.5 mm, l r = 1 mm, r = 3 mm, g1 = 0.5 mm, g2 = 0.3 mm, α1 = 15°, and the resistance of 105 is R = 170 Ω.

[0022] Figure 3 shows a schematic diagram of the lossless layer 4, where the gray area represents the metal patch. The lossless layer consists of a Jerusalem cross structure arranged periodically, with initial dimensions of: l 21 = 5.9 mm, l 22 = 3 mm, w 21 = 2 mm, w 22 = 0.5 mm.

[0023] Figure 4 shows the reflection coefficient curves of the integrated reflection and absorption structure with a wide range of adjustable reflection frequency band at different sizes. Figure 5 shows the simulation results of the absorption characteristics of an embodiment of the present invention; where the absorption efficiency is expressed by the formula A=1-|Γ| 2The calculated value is |Γ|, representing the magnitude of the reflection coefficient. Figures 4 and 5 show four reflection bands, RB1, RB2, RB3, and RB4, with gradually increasing frequency ranges, offering a wide adjustable range. The structural dimensions corresponding to these four bands are given in Table 1. The table shows that the bandwidth of all four reflection bands with reflection coefficients greater than -3dB is greater than 900MHz.

[0024] Table 1. Comparison of Structural Dimensions and Reflection Frequency Bands

[0025]

[0026] This invention proposes a reflective absorber with a wide range of adjustable reflection frequency bands. The reflection frequency band has a certain bandwidth and is not a single frequency. By changing the structural dimensions, the controllability of the reflection frequency band is achieved, which significantly improves the flexibility of its application.

Claims

1. A reflective absorber with a wide range of adjustable reflection frequency bands, characterized in that, include: The following layers are arranged from top to bottom: a lossy layer (1), a first dielectric layer (2), an air layer (3), a lossless layer (4), a second dielectric layer (5), and a ground layer (6). The lossy layer (1) is located on the upper surface of the first dielectric layer (2). The air layer (3) is between the first dielectric layer (2) and the lossless layer (4). The lossless layer (4) is located on the upper surface of the second dielectric layer (5). The ground layer (6) is located on the lower surface of the second dielectric layer (5). The reflection frequency band can be controlled over a wide range by controlling the length of the C-shaped groove in the lossy layer (1) and the length of the Jerusalem cross structure in the lossless layer (4). The lossy layer (1) is a periodic structure. Each unit of the periodic structure includes four circular patches (101), a transmission line connecting the circular patches, a C-shaped groove (102), and four connecting patches. The device consists of a chip (103), a square ring patch (104), and a resistor (105). A C-shaped groove (102) is etched on each circular patch (101). By changing the length of the C-shaped groove (102), its resonant frequency is changed to achieve the control of the transmission frequency. A resistor (105) is welded in the middle of each side of the square ring patch (104). Each corner of the square ring patch (104) is connected by a connecting patch (103) and a circular patch (101). The lossless layer (4) is periodically arranged in Jerusalem cross structure. The resonant frequency of the Jerusalem cross structure is affected by its length. By changing its length, the power frequency is controlled, which plays the role of adjusting the phase of the reflected wave to achieve a broadband high-selectivity reflection frequency band.

2. The reflective absorber with a wide range of adjustable reflection frequency band as described in claim 1, characterized in that, The first dielectric layer (2) has a height h1=0.5mm, an air layer thickness t=4.4mm, and a second dielectric layer (5) thickness h2=2.7mm.

3. The reflective absorber with a wide range of adjustable reflection frequency band as described in claim 2, characterized in that, The dielectric layer material has a relative permittivity of 2.65 and a loss tangent of 0.

002.

4. The reflective absorber with a wide range of adjustable reflection frequency band as described in claim 1, characterized in that, The total reflection coefficient of a reflective absorber is less than -10dB in both the low-frequency and high-frequency bands, indicating that it is in a wave-absorbing state.

5. The reflective absorber with a wide range of adjustable reflection frequency band as described in claim 1, characterized in that, The reflection band refers to a frequency band with a reflection coefficient modulus greater than -3dB, which is relatively wide and has a steep transition band. The reflection band can be adjusted over a wide range by simultaneously changing the length of the C-shaped groove etched on the circular patch in the lossy layer cell and the length of the Jerusalem cross cell in the lossless layer.

6. The reflective absorber with a wide range of adjustable reflection frequency band as described in claim 1, characterized in that, The absorption efficiency is expressed by the formula A = 1 - |Γ| 2 The calculation shows that |Γ| represents the magnitude of the reflection coefficient.

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