An ultra-wideband high-cut wave-absorbing and wave-transmitting integrated metasurface structure

Abstract

The application discloses an ultra-wideband high-stop absorbing-transmitting integrated metasurface structure, which comprises a plurality of metasurface units arranged in a periodic rectangular array; each metasurface unit comprises, from top to bottom, a loss layer, an air layer and a band-pass frequency selective surface layer; electromagnetic waves are input from the loss layer of the metasurface structure and then output through the air layer and the band-pass frequency selective surface layer. Under the joint action of the loss layer and the band-pass selective surface layer, the application realizes ultra-wideband transmission with a loss of less than 1 dB in the 8-12 GHz frequency band, and realizes high-efficiency absorption with an absorption rate of more than 80% in the 1.92-6.2 GHz and 14.03-18.26 GHz frequency bands, and has a steep transmission-absorption transition band. The application has a simple structure and a low profile, and effectively solves the problems of narrow transmission bandwidth and poor edge selectivity of a traditional absorbing-transmitting integrated structure.

Description

Technical Field

[0001] This invention relates to the field of artificial electromagnetic materials, and in particular to an ultrawideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure. Background Technology

[0002] With the rapid development of electronic information technology, modern communication, radar, and imaging systems are increasingly demanding electromagnetic wave manipulation. In complex electromagnetic environments, while traditional frequency-selective surfaces can achieve efficient transmission of signals in specific frequency bands, they typically exhibit strong reflection characteristics in non-operating frequency bands. This strong out-of-band reflection not only significantly increases the radar cross-section of the target, making it easier for radar to detect, but may also cause electromagnetic interference and crosstalk between channels. Therefore, there is an urgent need to develop an integrated structure that combines wave absorption and wave transmission functions, ensuring low-loss transmission of signals in the target frequency band while efficiently absorbing electromagnetic energy in non-operating frequency bands, thereby solving the bottleneck problems of functional dispersion, large device size, and insufficient stealth performance in high-frequency front-ends.

[0003] Currently, integrated absorbing-transmitting structures often employ a cascaded loss layer and frequency-selective surface layer. However, this approach still faces significant bottlenecks in practical engineering applications. First, there is a natural constraint between the transmission bandwidth and the absorption bandwidth. Traditional loss layers, when widening the absorption bandwidth, often introduce substantial parasitic conductance within the transmission window, leading to increased insertion loss within the transmission band and severely impacting communication quality. Second, existing structures often suffer from insufficient frequency selectivity, resulting in a less steep transition region between the transmission and absorption bands, i.e., a slow roll-off rate. This performance deficiency makes it difficult for the structure to effectively filter interference signals adjacent to the operating frequency band, failing to meet the stringent high-cutoff requirements of high-frequency systems.

[0004] To enhance the anti-interference capability of systems in complex electromagnetic environments, researchers have begun exploring optimized design paths based on dispersion modulation. Achieving ultra-wideband, low-loss transmission while simultaneously obtaining an extremely steep transmission-absorbing transition band and wideband dual-band absorption characteristics through precise resonance mechanism modulation is a crucial research topic in the field of electromagnetic modulation. Therefore, developing a simple, low-profile, and frequency-selective integrated absorption-transmission metasurface structure has significant engineering value for realizing the miniaturization, high integration, and multi-dimensional high-performance modulation of high-frequency systems. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides an ultrawideband high cutoff wave absorption-wave transmission integrated metasurface structure.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An ultrawideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure includes multiple metasurface units arranged in a periodic rectangular array; each metasurface unit includes a loss layer, an air layer, and a bandpass frequency selective surface layer arranged sequentially from top to bottom; the electromagnetic wave is input from the loss layer of the metasurface structure and output after passing through the air layer and the bandpass frequency selective surface layer.

[0007] The loss layer includes a first metal layer, a square first dielectric substrate, and a plurality of lumped resistors. The first metal layer is disposed on the side of the first dielectric substrate away from the bandpass frequency selection surface layer. The first metal layer consists of four L-shaped metal sheets and four meandering metal lines. The four L-shaped metal sheets are arranged symmetrically at the four corners of the first dielectric substrate. Every two L-shaped metal sheets are connected by meandering metal lines. Each meandering metal line is a metal line wound into a comb-like outer contour. The meandering metal lines are disposed on the inner side of the first dielectric substrate opposite to the L-shaped metal sheets. Lumped resistors are disposed on the L-shaped metal sheets.

[0008] Each of the L-shaped metal sheets has at least one metal gap on each of its two sides, and each of the metal gaps contains a lumped resistor; the plurality of lumped resistors are symmetrically distributed about the center of the first dielectric substrate, and the lumped resistors on the same L-shaped metal sheet are axially symmetrical about the angle bisector of the L-shaped metal sheet.

[0009] The bandpass frequency selective surface layer is composed of a multi-layer cascade structure, including a second metal layer, a second dielectric substrate, a third metal layer, a third dielectric substrate, and a fourth metal layer arranged sequentially from top to bottom. The second metal layer and the first dielectric substrate of the loss layer are separated by an air gap layer.

[0010] The second and fourth metal layers are both metal disc structures, and the second and third dielectric substrates are both square structures. The third metal layer adopts a hollow square frame structure, that is, in a single metasurface unit, one third metal layer is a hollow square frame structure. In the metasurface structure, the third metal layers are periodically arranged in a rectangular array to form a mesh-like metal grid structure. The centers of the second metal layer, the second dielectric substrate, the third metal layer, the third dielectric substrate, and the fourth metal layer are located on the same straight line.

[0011] The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate use the same insulating material.

[0012] In a single metasurface unit, both the loss layer and the bandpass frequency selection surface are square structures with the same side length; the centers of the first metal layer, the first dielectric substrate, the second metal layer, the second dielectric substrate, the third metal layer, the third dielectric substrate, and the fourth metal layer are located on the same straight line.

[0013] The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure array is composed of metasurface units arranged in a periodic rectangular array.

[0014] The ultra-wideband high cutoff absorption-transmission integrated metasurface structure can achieve broadband and efficient absorption at both low and high frequencies while ensuring low-loss transmission at mid-frequency, and has a steep transition band.

[0015] The beneficial effects of this invention are: (1) This invention discloses an ultra-wideband high-cutoff absorption-transmission integrated metasurface structure. The proposed structure consists of a loss layer and a bandpass frequency selective surface cascaded together. The loss layer is composed of folded square ring metal units with loaded lumped resistance. By introducing multi-resonant losses on both the low-frequency and high-frequency sides, it achieves dual-wideband absorption at low and high frequencies, while maintaining relatively small insertion loss in the mid-frequency band. The bandpass frequency selective surface is formed by cascading three metal units, which effectively delays the generation of grating lobes and broadens the transmission bandwidth.

[0016] (2) The loss layer and frequency-selective layer of the present invention work together after cascading to achieve a frequency response of approximately a rectangular window across the entire operating frequency band—flat transmission in the mid-frequency band, wide absorption on both sides, and a steep transition region. The metasurface structure of the present invention is centrally symmetrical about the unit center, giving the overall material dual-polarization characteristics. This metasurface design has good engineering potential for applications such as broadband stealth radomes, broadband radar systems, and front-end electromagnetic protection in complex electromagnetic environments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the loss layer included in the metasurface structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the bandpass frequency selective surface included in the metasurface structure in an embodiment of the present invention, wherein, Figure 3 (a) is a schematic diagram of the top layer of the bandpass frequency selective surface. Figure 3 (b) is a schematic diagram of the intermediate layer of the bandpass frequency selection surface; Figure 4 This is an equivalent circuit diagram of the ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure in an embodiment of the present invention; Figure 5The above figures show the simulation results of the transmission coefficient and absorption rate of the ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure in the embodiment of the present invention. Figure 6 The transmission electric field distribution diagrams obtained by simulation at different frequency points of the ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure in the embodiment of the present invention are shown.

[0018] In the figure: 1. First metal layer, 2. First dielectric substrate, 3. Second metal layer, 4. Second dielectric substrate, 5. Third metal layer, 6. Third dielectric substrate, 7. Fourth metal layer, 8. Lumped resistor. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] An ultrawideband high-cutoff integrated absorption-transmission metasurface structure comprises multiple metasurface units arranged in a periodic rectangular array as needed. Each metasurface unit is a multi-layer cascaded structure from top to bottom, including a loss layer, an air layer, and a bandpass frequency selective surface layer arranged sequentially from top to bottom. Electromagnetic waves are input from the loss layer of the metasurface structure and output after passing through the air layer and the bandpass frequency selective surface layer. This ultrawideband high-cutoff integrated absorption-transmission metasurface structure can achieve broadband and efficient absorption at low and high frequencies on both sides while ensuring low-loss transmission at mid-frequency, and has a steep transition band.

[0021] The loss layer includes a first metal layer 1, a square first dielectric substrate 2, and multiple lumped resistors 8. The first metal layer 1 is etched and disposed on the side of the first dielectric substrate 2 away from the bandpass frequency selection surface layer. The first metal layer 1 consists of four L-shaped metal sheets and four meandering metal lines. The four L-shaped metal sheets are arranged symmetrically at the four corners of the first dielectric substrate 2, that is, the right angles of the L-shaped metal sheets are matched with the four corners of the first dielectric substrate 2. Each pair of L-shaped metal sheets is connected by a meandering metal line. Each meandering metal line is a metal line wound into a comb-like outer contour. The meandering metal line is disposed on the inner side of the first dielectric substrate 2 relative to the L-shaped metal sheets. Lumped resistors 8 are disposed on the L-shaped metal sheets.

[0022] Each L-shaped metal sheet has at least one metal gap on each of its two sides, and a lumped resistor 8 is loaded in each metal gap; the multiple lumped resistors 8 are symmetrically distributed about the center of the first dielectric substrate 2, and the lumped resistors 8 on the same L-shaped metal sheet are axially symmetrical about the angle bisector of the L-shaped metal sheet, so that each L-shaped metal sheet has an equal number of lumped resistors 8.

[0023] Specifically, the loss layer includes a first dielectric substrate 2 and a first metal layer 1 deposited on the upper surface of the first dielectric substrate 2; the first metal layer 1 is composed of a folded metal square ring loaded with a lumped resistor 8; the folded metal square ring has metal gaps of the same size at the center of each of its four sides, and meandering metal lines are connected at the metal gaps; the meandering metal lines are formed by multiple short metal lines that are orthogonal to each other and connected end to end on the inner side of the folded metal square ring; each side of the folded metal square ring has a metal gap at each end, the gaps are of the same size, and the distance to the two vertices is the same; the metal structure of the first metal layer 1 is centrally symmetrical about the center point of the unit.

[0024] For example, the lumped resistor 8 has a resistance of 160Ω and is loaded in the metal gaps at both ends of the four sides of the folded metal square ring; the folded metal square ring is loaded with a total of 8 lumped resistors 8, and is centrally symmetrical about the center point of the unit of the first dielectric substrate 2.

[0025] The bandpass frequency selective surface layer is composed of a multi-layer cascaded structure, including a second metal layer 3, a second dielectric substrate 4, a third metal layer 5, a third dielectric substrate 6, and a fourth metal layer 7 arranged sequentially from top to bottom. The second metal layer 3 and the first dielectric substrate 2 of the loss layer are separated by an air layer. Each pair of adjacent metal layers is separated by a dielectric layer of the same thickness; that is, the second dielectric substrate 4 separates the second metal layer 3 and the third metal layer 5, and the third dielectric substrate 6 separates the third metal layer 5 and the fourth metal layer 7.

[0026] The second metal layer 3 and the fourth metal layer 7 are both metal disc structures of the same size, and the second dielectric substrate 4 and the third dielectric substrate 6 are both square structures. The third metal layer 5 adopts a hollow square frame structure, that is, in a single metasurface unit, one third metal layer 5 is a hollow square frame structure. In the metasurface structure, the third metal layers 5 are laid out in an array to form a mesh-like metal grid structure. The centers of the second metal layer 3, the second dielectric substrate 4, the third metal layer 5, the third dielectric substrate 6 and the fourth metal layer 7 are located on the same straight line.

[0027] The first dielectric substrate 2, the second dielectric substrate 4, and the third dielectric substrate 6 use the same insulating material.

[0028] Both the loss layer and the bandpass frequency selection surface layer are square structures with the same outer contour, that is, they have the same side length, and the centers of the first metal layer 1, the first dielectric substrate 2, the second metal layer 3, the second dielectric substrate 4, the third metal layer 5, the third dielectric substrate 6 and the fourth metal layer 7 are located on the same straight line.

[0029] The miniaturized ultrawideband high cutoff integrated absorbing-transmitting metasurface structure array is composed of absorbing-transmitting integrated metasurface units arranged in a periodic rectangular array.

[0030] The metasurface unit includes a loss layer and a bandpass frequency selective surface. The loss layer is located above the bandpass frequency selective surface, and the loss layer and the bandpass frequency selective surface are separated by an air gap layer. The loss layer includes a first dielectric substrate 2 and a folded metal square ring with a lumped resistance 8 deposited on the upper surface of the first dielectric substrate 2, i.e., a first metal layer 1. Under the combined action of the loss layer and the bandpass frequency selective surface, the present invention achieves ultra-wideband wave transmission with an insertion loss of less than 1dB in the 8~12GHz frequency band, and achieves high-efficiency wave absorption with an absorption rate of over 80% in the 1.92~6.2GHz and 14.03~18.26GHz frequency bands, and has a steep wave transmission-absorption transition band. The present invention has a simple structure and low profile, effectively solving the problems of narrow wave transmission bandwidth and poor edge selectivity of traditional integrated absorption and transmission structures.

[0031] This embodiment provides an ultrawideband high-cutoff integrated absorption-transmission metasurface structure. The metasurface structure includes at least one metasurface unit, as shown in the schematic diagram of the metasurface unit structure. Figure 1 As shown, the metasurface structure adopts a multi-layer cascaded configuration, which includes, from top to bottom, a loss layer, an air gap layer, and a bandpass frequency selective surface layer.

[0032] In a specific embodiment, see Figure 1 Both the loss layer and the bandpass frequency selective surface are square structures with a side length p = 13.35 mm; the air layer thickness is h = 13.4 mm.

[0033] The loss layer includes a first metal layer 1 and a first dielectric substrate 2. The structural pattern of the first metal layer 1 is centrally symmetrical about the center point of the unit, and its main body is a folded metal square ring loaded with a lumped resistor 8. Each of the four sides of the folded metal square ring has a central metal slot of equal size, and a meandering metal line connects to the metal slot. The meandering metal line is located in the inner region of the folded metal square ring and is formed by splicing together multiple short, straight metal strips that are orthogonal to each other. Furthermore, each side of the folded metal square ring has metal slots at both ends for loading the lumped resistor 8. The two metal slots on the same side are of the same size and are equidistant from the adjacent vertex of that side.

[0034] In the metal gaps at both ends of the four sides of the folded metal square ring, a lumped resistor 8 with a resistance of 160Ω is connected across each side; the first metal layer 1 contains a total of eight lumped resistors.

[0035] In a specific embodiment, see Figure 2The folded metal square ring has a side length l1 = 12.55 mm and a main metal strip width w2 = 0.7 mm. The metal gap width at the center of each side of the square ring is w1 = 1.36 mm. The width of the wide metal strip on both sides of the metal gap at the center of each side is w3 = 2.12 mm. Near the ends of each side of the folded metal square ring, the metal gap width for mounting lumped resistors is g1 = 0.5 mm. The overall linewidth of the meandering metal wire is w4 = 0.1 mm. The length of the short metal strip in the x-direction is l2 = 0.93 mm, and the length of the metal strip directly connected to the outer folded metal square ring in the y-direction is l3 = 0.4 mm. Furthermore, the spacing between the meandering metal wire traces in the y-direction is g2 = 0.2 mm, and the spacing between the outer edge of the meandering metal wire and the inner edge of the folded metal square ring in the x-direction is g3 = 0.2 mm. The first dielectric substrate 2 is made of F4B220 material with a relative permittivity of 2.2 and a loss tangent of 0.003, and a thickness of h2=0.4mm.

[0036] The bandpass frequency selective surface is composed of a multi-layer cascade structure, including a second metal layer 3, a third metal layer 5, a fourth metal layer 7, a second dielectric substrate 4, and a third dielectric substrate 6; each pair of adjacent metal layers is separated by a dielectric layer of the same thickness. Among them, the second metal layer 3 and the fourth metal layer 7 are metal disc structures of the same size; the third metal layer 5 is a metal grid structure.

[0037] In a specific embodiment, see Figure 3 The radius of the metal discs in the second metal layer 3 and the fourth metal layer 7 is c = 3.76 mm; the width of the metal grid structure in the third metal layer 5 is g5 = 2.35 mm. The second dielectric substrate 4 and the third dielectric substrate 6 are both made of F4B220 material with a relative permittivity of 2.2 and a loss tangent of 0.003, and have the same thickness of h3 = 1.65 mm.

[0038] Specifically, the equivalent circuit model of the ultra-wideband high-cutoff integrated absorber-transmitter metasurface structure is as follows: Figure 4 As shown. The loss layer can be characterized as a series connection of parallel circuits RL1C1 and L2C2. The upper and lower surface metal discs of the bandpass frequency selective surface can be equivalent to series resonant circuits of capacitor C3 and inductor L3, and capacitor C4 and inductor L5, respectively. The metal grid has high-pass characteristics; therefore, the middle layer of the bandpass frequency selective surface can be equivalent to an inductor L4. The first dielectric substrate 2 uses impedance Z... sub1 This indicates that the second dielectric substrate 4 and the third dielectric substrate 6 use impedance Z. sub2 The free-space characteristic impedance is denoted as Z0.

[0039] The technical effects of the present invention will be further explained below with reference to simulation experiments: The electromagnetic simulation results obtained by modeling and simulating the embodiments of the present invention using the commercial simulation software CST are as follows: Figure 5 As shown. Figure 5 The horizontal axis represents the frequency value in GHz, the left vertical axis represents the S-parameters, and the right vertical axis represents the absorption rate. Figure 5 The solid green line in the diagram represents the transmission coefficient |S|. 21 | The solid red line is the absorption rate curve.

[0040] Reference Figure 5 When electromagnetic waves are incident perpendicularly, the transmission coefficient of the ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure is 8~12GHz at -1dB, and the wave-absorbing band frequencies with absorption rates of over 80% are 1.92~6.2GHz and 14.03~18.26GHz, respectively, and it has a steep wave-transmitting-absorbing transition band.

[0041] Figure 6 This paper presents the transmission electric field distribution of an ultra-wideband high-cutoff integrated absorbing-transmitting metasurface structure at different frequency points, obtained through simulation. In the absorption bands of low frequencies (e.g., 3 GHz, 5 GHz) and high frequencies (e.g., 15 GHz, 17 GHz), electromagnetic waves are almost completely blocked by the integrated absorbing-transmitting metasurface and cannot penetrate the structure, indicating that the integrated absorbing-transmitting metasurface has effective absorption characteristics in these two frequency bands. This absorption efficiency is mainly attributed to the loss layer in the design, which has excellent electromagnetic wave energy absorption capabilities. In the mid-frequency range (e.g., 9 GHz, 11 GHz), electromagnetic waves exhibit almost lossless transmission characteristics. Signals in this frequency band can smoothly penetrate the integrated absorbing-transmitting metasurface with almost no additional loss, indicating that the structure has excellent transmission performance in this frequency band, achieving low-loss signal transmission. This phenomenon is consistent with the electromagnetic simulation results presented earlier. The absorption characteristics of the integrated absorbing-transmitting metasurface structure are significant in the low and high frequency ranges, while it exhibits ideal transmission performance in the mid-frequency range, proving that it possesses both efficient absorption and transmission capabilities over a wide frequency range.

[0042] Although specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A superwideband high-cutoff integrated metasurface structure for absorbing and transmitting waves, characterized in that, It includes multiple metasurface units, which are arranged in a periodic rectangular array. Each metasurface unit includes a loss layer, an air layer, and a bandpass frequency selective surface layer arranged from top to bottom. The electromagnetic wave is input from the loss layer of the metasurface structure and output after passing through the air layer and the bandpass frequency selective surface layer.

2. The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure according to claim 1, characterized in that, The loss layer includes a first metal layer (1), a square first dielectric substrate (2), and a plurality of lumped resistors (8). The first metal layer (1) is disposed on the side of the first dielectric substrate (2) away from the bandpass frequency selection surface layer. The first metal layer (1) consists of four L-shaped metal sheets and four meandering metal lines. The four L-shaped metal sheets are arranged symmetrically at the four corners of the first dielectric substrate (2) with respect to the center. Each pair of L-shaped metal sheets is connected by a meandering metal line. Each meandering metal line is a metal line wound into a comb-like outer contour. The meandering metal line is disposed on the inner side of the first dielectric substrate (2) relative to the L-shaped metal sheets. Lumped resistors (8) are disposed on the L-shaped metal sheets.

3. The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure according to claim 1, characterized in that, Each of the L-shaped metal sheets has at least one metal gap on each side, and each metal gap is loaded with a lumped resistor (8); the multiple lumped resistors (8) are symmetrically distributed with respect to the center of the first dielectric substrate (2), and the lumped resistors (8) on the same L-shaped metal sheet are axially symmetrical about the angle bisector of the L-shaped metal sheet.

4. The ultra-wideband high cutoff integrated metasurface structure for absorbing and transmitting waves according to claim 1, characterized in that, The bandpass frequency selective surface layer includes a second metal layer (3), a second dielectric substrate (4), a third metal layer (5), a third dielectric substrate (6), and a fourth metal layer (7) arranged sequentially from top to bottom. The second metal layer (3) and the first dielectric substrate (2) of the loss layer are separated by an air gap layer.

5. The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure according to claim 4, characterized in that, The second metal layer (3) and the fourth metal layer (7) are both metal disc structures, and the second dielectric substrate (4) and the third dielectric substrate (6) are both square structures; the third metal layer (5) adopts a hollow square frame structure; the centers of the second metal layer (3), the second dielectric substrate (4), the third metal layer (5), the third dielectric substrate (6) and the fourth metal layer (7) are located on the same straight line.

6. The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure according to claim 1, characterized in that, The first dielectric substrate (2), the second dielectric substrate (4), and the third dielectric substrate (6) are made of the same insulating material.

7. The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure according to claim 1, characterized in that, In a single metasurface unit, both the loss layer and the bandpass frequency selection surface are square structures with the same side length; the centers of the first metal layer (1), the first dielectric substrate (2), the second metal layer (3), the second dielectric substrate (4), the third metal layer (5), the third dielectric substrate (6), and the fourth metal layer (7) are located on the same straight line.

8. The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure according to claim 1, characterized in that, The ultra-wideband high cutoff wave-absorbing and wave-transmitting integrated metasurface structure array is composed of metasurface units arranged in a periodic rectangular array.

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