A frequency-selective reflector absorber with two adjustable reflection frequency bands.

Abstract

This invention discloses a frequency-selective reflector absorber with two adjustable reflection frequency bands, comprising, from top to bottom: a lossy layer, a first dielectric layer, a lossless layer, a second dielectric layer, and a metallized ground layer; and, from top to bottom: a lossy layer, a first dielectric layer, an air layer, a lossless layer, a second dielectric layer, and a metallized ground layer. The lossy layer is located on the upper surface of the first dielectric layer; the lossless layer is located on the upper surface of the second dielectric layer; the metallized ground layer is located on the lower surface of the second dielectric layer; and an air layer is located between the two dielectric layers. In the frequency domain, the frequency bands, from low to high frequency, are: a first absorbing frequency band AB1, a first adjustable reflection frequency band LRB, a second absorbing frequency band AB2, a second adjustable reflection frequency band HRB, and a third absorbing frequency band AB3. The first adjustable reflection frequency band LRB and the second adjustable reflection frequency band HRB are individually or simultaneously adjustable by changing the structural dimensions of the absorber. This invention achieves wide-range independent and simultaneous control of the two reflection frequency bands, significantly improving its application flexibility in multi-frequency antennas.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic materials technology, and in particular to a frequency-selective reflector with two adjustable reflection frequency bands. Background Technology

[0002] Reflector antennas typically use a metallic reflector to reflect and focus electromagnetic waves, thereby improving antenna gain. However, the reflection from the metallic ground plane results in a large radar cross-section for the antenna. To reduce the radar cross-section of the antenna without affecting gain, researchers have recently proposed the concept of frequency-selective reflective absorbers, and have achieved some research progress and results.

[0003] Frequency-selective reflective absorbers are special artificial electromagnetic materials that reflect electromagnetic waves within a specific frequency band and absorb them in other bands. When used as the reflector of an antenna, this absorber functions as a totally reflected metal floor in the reflection band; in the absorption band, the incident electromagnetic waves are absorbed, thus reducing the antenna's radar cross-section. In recent years, researchers have proposed frequency-selective reflective absorbers with absorption-reflection-absorption functions. Typically, these absorbers only have one reflection band, which limits their use in multi-frequency reflector antennas. Summary of the Invention

[0004] Purpose of the invention: The present invention provides a frequency selective reflector absorber with two reflective frequency bands that can be adjusted over a wide range. The two reflective frequency bands can be adjusted over a wide range by changing the structure.

[0005] Technical Solution: The present invention discloses a frequency selective reflector with two adjustable reflection frequency bands, comprising, from top to bottom: a lossy layer 1, a first dielectric layer 4, a lossless layer 2, a second dielectric layer 5, and a metallized ground layer 3; and, from top to bottom: a lossy layer 1, a first dielectric layer 4, an air layer 6, a lossless layer 2, a second dielectric layer 5, and a metallized ground layer 3; the lossy layer 1 is located on the upper surface of the first dielectric layer 4; the lossless layer 2 is located on the upper surface of the second dielectric layer 5; the metallized ground layer 3 is located on the lower surface of the second dielectric layer 5; and an air layer 6 is located between the two dielectric layers. In the frequency domain, the frequency bands are arranged from low to high frequency as follows: first absorption frequency band AB1, first adjustable reflection frequency band LRB, second absorption frequency band AB2, second adjustable reflection frequency band HRB, and third absorption frequency band AB3; wherein the first adjustable reflection frequency band LRB and the second adjustable reflection frequency band HRB are individually or simultaneously adjustable by changing the structural dimensions of the absorber.

[0006] Furthermore, the lossy layer 1 is composed of periodically arranged resonant units with resistive loading. Each resonant unit comprises two parts: the first part consists of four circular patches 101 etched with C-shaped slots 102, and the second part consists of square patches 103 etched with zigzag slots 104. The two parts are connected by four patch resistors 105. This structure serves a wave absorption-wave transmission-wave absorption-wave transmission-wave absorption function.

[0007] Furthermore, the lossless layer 2 is composed of Jerusalem cross structures and deformed cross structures arranged at intervals and periods, which plays a role in adjusting the phase of the reflected wave.

[0008] Furthermore, the modulation of the LRB in the first tunable reflection band is achieved by changing the length of the C-shaped gap 102 in the circular patch on the lossy layer 1 and the length of the Jerusalem cross structure in the lossless layer 2.

[0009] Furthermore, the second adjustable reflection frequency band is controlled by changing the length of the tortuous gap 104 in the square patch on the lossy layer 1 and the length of the deformed cross structure in the lossless layer 2.

[0010] Furthermore, the thickness of the air layer 6 is t=4.4mm, the height of the first dielectric layer 4 is h1=0.5mm, and the thickness of the second dielectric layer 5 is h2=2.7mm.

[0011] Furthermore, the relative permittivity of the materials of the first dielectric layer 4 and the second dielectric layer 5 is 2.65, and the loss tangent is 0.002.

[0012] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention realizes large-scale independent and simultaneous control of two reflection frequency bands, which significantly improves its application flexibility in multi-frequency antennas. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention.

[0014] Figure 2 This is a schematic diagram of the unit structure of the lossy layer in this invention.

[0015] Figure 3 This is a schematic diagram of the unit structure of the lossless layer in this invention.

[0016] Figure 4 This is a simulation result diagram of the first reflection frequency band modulation of the present invention.

[0017] Figure 5 This is a simulation result diagram of the second reflection frequency band modulation of the present invention.

[0018] Figure 6 This is a simulation result diagram of the two reflection frequency bands being simultaneously adjustable according to the present invention. Detailed Implementation

[0019] like Figure 1 As shown, a frequency-selective reflector with two adjustable reflection bands comprises, from top to bottom: a lossy layer 1, a first dielectric layer 4, an air layer 6, a lossless layer 2, a second dielectric layer 5, and a metallized ground layer 3. The lossy layer 1 is located on the upper surface of the first dielectric layer 4; the lossless layer 2 is located on the upper surface of the second dielectric layer 5; the metallized ground layer 3 is located on the lower surface of the second dielectric layer 5; and the air layer 6 is located between the two dielectric layers. This frequency-selective reflector performs absorption, reflection, and other functions in five frequency bands, and the frequency bands in the order from low to high frequency in the frequency domain are: first absorption band AB1, first adjustable reflection band LRB, second absorption band AB2, second adjustable reflection band HRB, and third absorption band AB3. The first adjustable reflection band LRB and the second adjustable reflection band HRB are individually or simultaneously adjustable over a wide range by changing the structural dimensions of the absorber. The LRB modulation of the first adjustable reflection band is achieved by changing the length of the C-shaped slot in the circular patch on the lossy layer and the length of the Jerusalem cross structure in the lossless layer. The modulation of the second adjustable reflection band is achieved by changing the length of the tortuous slot in the square patch on the lossy layer and the length of the deformed cross structure in the lossless layer.

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

[0021] Lossy layer 1 consists of a periodic array, and its unit structure diagram is shown below. Figure 2 As shown in the figure, gray represents metal chips, and black represents resistors. Each unit consists of four circular chips 101, one square chip 103, and four chip resistors 105. Each circular chip 101 has a C-shaped slit 102 etched in it; the square chip 103 has a zigzag slit 104 etched in it; and each chip resistor 105 is connected to the circular and square chips 101 via copper foil wires. The structural dimensions shown in the figure are adjusted according to actual performance requirements. The initial values ​​of the structural dimensions in this embodiment are P=16mm, l 12 = 1.3mm, l 15 = 4.5 mm, l 16 = 1 mm, l 17 = 2.1 mm, w 13 = 0.3 mm, w 14 = 0.4 mm, w 15 = 0.8 mm, w 16 = 0.3 mm, w17 = 0.2 mm, l r = 1 mm, r = 3 mm, g1 = 0.5 mm, g2 = 0.3 mm, g3 = 0.3 mm, α1 = 15°, the resistance of 105 is R1 = 170 Ω.

[0022] The unit structure of lossless layer 2 is as follows Figure 3 As shown in the figure, dark gray represents the metal patch, and light gray represents the dielectric substrate. The lossless layer consists of a Jerusalem cross structure and a deformed cross structure arranged periodically. The initial dimensions in the figure are as follows: l 21 = 7mm, l 22 = 2.5 mm, l 23 = 6.7 mm, l 24 = 1 mm, w 21 = 1 mm, w 22 = 1.5 mm, w 23 = 1 mm.

[0023] Figure 4 The figure shows simulation results of the first adjustable reflection band (LRB) of the frequency selective reflector absorber with two adjustable reflection bands at different sizes. As can be seen from the figure, for reflection coefficients greater than -3dB, the first adjustable reflection band can be adjusted within the ranges of LRB1, LRB2, and LRB3, while the second adjustable reflection band (HRB) remains almost constant. The absorption bands with reflection coefficients less than -10dB are AB1, AB2, and AB3. Due to the adjustment of the first adjustable reflection band, the bandwidths of the first absorption band AB1 and the second absorption band AB2 change with the reflection band, while the third absorption band AB3 remains almost unchanged. The correspondence between structural dimensions and the first adjustable reflection band is listed in Table 1, where |Γ| represents the magnitude of the reflection coefficient.

[0024] Table 1. Comparison of Structural Dimensions and First Adjustable Reflection Band

[0025]

[0026] Figure 5The figure shows simulation results of the second adjustable reflection band (HRB) of a frequency-selective reflector with two adjustable reflection bands at different sizes. As can be seen from the figure, for reflection coefficients greater than -3dB, the second adjustable reflection band can be adjusted within the ranges of HRB1, HRB2, and HRB3, while the first adjustable reflection band (LRB) remains almost unchanged. The absorption bands with reflection coefficients less than -10dB are AB1, AB2, and AB3, respectively. Due to the adjustment of the second adjustable reflection band, the bandwidths of the second absorption band AB2 and the third absorption band AB3 change with the reflection band, while the first absorption band AB1 remains almost unchanged. The correspondence between structural dimensions and the first adjustable reflection band is listed in Table 2.

[0027] Figure 6 The figure shows the simulation results of simultaneously adjustable two reflection frequency bands according to an embodiment of the present invention. As can be seen from the figure, the first and second reflection frequency bands are simultaneously adjustable. LRB1 and LRB2 are the lowest and highest adjustable frequency bands of the first reflection frequency band, respectively, and HRB1 and HRB2 are the lowest and highest adjustable frequency bands of the second reflection frequency band, respectively. The absorption frequency bands AB1, AB2, and AB3, with a reflection coefficient less than -10dB, change with the two adjustable reflection frequency bands. The correspondence between structural dimensions and adjustable reflection frequency bands is listed in Table 3.

[0028] Table 2. Comparison of Structural Dimensions and Second Adjustable Reflection Band

[0029]

[0030] Table 3. Comparison of Structural Dimensions and Simultaneous Adjustment of Two Reflection Bands

[0031]

Claims

1. A frequency-selective reflector with two 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 (4), a lossless layer (2), a second dielectric layer (5), and a metallized ground layer (3); the following layers are arranged from top to bottom: a lossy layer (1), a first dielectric layer (4), an air layer (6), a lossless layer (2), a second dielectric layer (5), and a metallized ground layer (3); the lossy layer (1) is located on the upper surface of the first dielectric layer (4), the lossless layer (2) is located on the upper surface of the second dielectric layer (5), and the metallized ground layer (3) is located on the lower surface of the second dielectric layer (5), with an air layer (6) between the two dielectric layers; the lossy layer (1) is composed of a periodically arranged resonant unit with resistive loading, wherein the resonant unit contains two parts, the first part being four C-shaped slots etched on them. The circular patch (101) of (102) is a square patch (103) with etched tortuous slits (104) and the two parts are connected by four patch resistors (105); the lossless layer (2) is composed of Jerusalem cross structure and deformed cross structure arranged periodically to adjust the phase of the reflected wave; in the frequency domain, the order from low frequency to high frequency is as follows: first absorbing frequency band AB1, first adjustable reflection frequency band LRB, second absorbing frequency band AB2, second adjustable reflection frequency band HRB, and third absorbing frequency band AB3; among which the first adjustable reflection frequency band LRB and the second adjustable reflection frequency band HRB are individually or simultaneously adjustable by changing the structural size of the absorber.

2. The frequency-selective reflector absorber with two adjustable reflection frequency bands as described in claim 1, characterized in that, The modulation of the LRB in the first adjustable reflection band is achieved by changing the length of the C-shaped gap (102) in the circular patch on the lossy layer (1) and the length of the Jerusalem cross structure in the lossless layer (2).

3. The frequency-selective reflector absorber with two adjustable reflection frequency bands as described in claim 1, characterized in that, The second adjustable reflection frequency band is controlled by changing the length of the tortuous gap (104) in the square patch on the lossy layer (1) and the length of the deformed cross structure in the lossless layer (2).

4. The frequency-selective reflector absorber with two adjustable reflection frequency bands as described in claim 1, characterized in that, The thickness of the air layer (6) is t=4.4mm, the height of the first dielectric layer (4) is h1=0.5mm, and the thickness of the second dielectric layer (5) is h2=2.7mm.

5. The frequency-selective reflector absorber with two adjustable reflection frequency bands as described in claim 1, characterized in that, The relative permittivity of the materials of the first dielectric layer (4) and the second dielectric layer (5) is 2.65, and the loss tangent is 0.002.

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