Three-dimensional multi-layer wave-absorbing metamaterial compounded along propagation direction based on antenna reciprocity

Abstract

The invention discloses a three-dimensional multilayer wave-absorbing metamaterial compounded along a propagation direction based on antenna reciprocity, and belongs to the field of three-dimensional wave-absorbing metamaterials. The structure comprises an upper layer dielectric substrate and metal patch cross grid, a lower layer dielectric substrate and metal patch cross grid, a dielectric substrate and a metal floor from top to bottom, the lower layer unit period is 1 / 2 of the upper layer unit period, and the unit number proportion of the upper layer to the lower layer is 1: 4; the upper layer achieves 2.55-8.23 GHz wave absorption, the lower layer achieves 7.87-18 GHz wave absorption, and 2.55-15.79 GHz broadband dual-polarization wave absorption is achieved after compounding. The metamaterial adopts the antenna reciprocity theorem to simplify the design, expands the frequency band through the double-layer self-similar structure, has the advantages of light weight, good mechanical property and easiness in assembly, and can be applied to the fields of electromagnetic safety, electromagnetic compatibility and the like.

Description

Technical Field

[0001] This invention belongs to the field of three-dimensional absorbing metamaterials, specifically relating to a three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and composite along the propagation direction. Background Technology

[0002] Metamaterials are a type of multifunctional artificial composite material whose structure is formed by periodically arranging subwavelength array units. Unlike natural materials, by designing periodic units, they can possess negative permittivity and negative permeability, thereby generating a variety of unconventional electromagnetic properties, such as negative refraction, superlensing, wave absorption, and focusing.

[0003] Currently, the design of two-dimensional absorbing metamaterials is quite mature, but limitations due to their planar structure still hinder their ability to achieve broadband, multi-polarized, and large-angle absorption. Furthermore, the small unit size makes the fabrication of multilayer two-dimensional metamaterials challenging and prone to center misalignment errors. In contrast, three-dimensional absorbing metamaterials offer superior properties such as low profile and light weight, ease of assembly, and excellent mechanical properties. The porous, three-dimensional structure of three-dimensional metamaterials can optimize the incident path of electromagnetic waves, extend the loss path, and improve impedance matching. The emergence of three-dimensional metamaterials with broadband absorption properties is of great significance for the development of electromagnetic safety and electromagnetic compatibility.

[0004] Three-dimensional metamaterials are mainly realized through the spatial design of metallic, magnetic, and resistive film materials, or through the combination of multiple materials. Among these, metallic materials offer greater design flexibility, lower density, and more mature fabrication methods compared to magnetic materials, making them easier to process. Therefore, by combining the advantages of three-dimensional metamaterials and metallic materials, a three-dimensional mesh structure can be designed and the metallic patch units optimized. Combined with a multilayer self-similar structure, a three-dimensional multilayer microwave absorbing metamaterial covering the 2.55-15.79 GHz band can be completed, exhibiting characteristics such as wide bandwidth, full polarization, easy assembly, and good mechanical properties. Summary of the Invention

[0005] The purpose of this invention is to propose a three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and composite along the propagation direction, which can broaden the absorption bandwidth by compositing self-similar structures of different sizes along the propagation direction.

[0006] The technical solution to achieve the purpose of this invention is as follows: a three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and composite along the propagation direction. The structure of the absorbing metamaterial, from top to bottom, consists of an upper dielectric substrate and metal patch cross grid, a lower dielectric substrate and metal patch cross grid, a dielectric substrate, and a metal ground plane. The upper dielectric substrate and metal patch cross grid are placed in a cross shape parallel to the electromagnetic wave propagation direction. On the mutually perpendicular dielectric substrate planes, there are first axisymmetric dipole antennas located at the center of the plane. The arrangement of the dielectric substrate and dipole antennas in the lower dielectric substrate and metal patch cross grid is the same as that of the upper layer, and a second axisymmetric dipole antenna is attached. The period of the lower layer unit is 1 / 2 of the period of the upper layer unit, and the ratio of the number of units in the upper and lower layers is 1:4.

[0007] Compared with the prior art, the significant advantages of this invention are:

[0008] (1) The designed three-dimensional absorbing metamaterial can achieve broadband dual-polarized electromagnetic wave absorption of 2.5-15.8GHz at a profile height of 15.5mm, and the absorption units acting on TE polarization and TM polarization are independent.

[0009] (2) The metal structure design of the designed three-dimensional absorbing metamaterial adopts the antenna reciprocity theorem. By replacing the port with lumped elements, the design process of the metal patch unit is simplified.

[0010] (3) The designed three-dimensional absorbing metamaterial uses a composite of two-layer self-similar structures to extend the absorbing frequency band, providing a reusable frequency band extension design method.

[0011] (4) The designed three-dimensional absorbing metamaterial has the advantages of being lightweight, having better mechanical load-bearing performance, and being easy to assemble compared with the previous two-dimensional absorbing metamaterial. Attached Figure Description

[0012] Figure 1 This is a three-dimensional exploded view of the three-dimensional multilayer metamaterial unit of the present invention.

[0013] Figure 2 This is a schematic diagram of the three-dimensional multilayer metamaterial plate structure of the present invention.

[0014] Figure 3 This is a top view of the three-dimensional multilayer metamaterial unit of the present invention.

[0015] Figure 4 This is a side view of the three-dimensional multilayer metamaterial unit of the present invention.

[0016] Figure 5 The image shows the front view and structural parameter annotations of the upper axisymmetric antennas (5, 6) of this invention.

[0017] Figure 6The image shows the front view and structural parameter annotations of the lower axisymmetric antennas (7, 8) of this invention.

[0018] Figure 7 The S11 curve of the three-dimensional multilayer metamaterial of the present invention under TE polarized incident light is shown.

[0019] Figure 8 The power density distribution of the three-dimensional multilayer metamaterial of the present invention on the metal and dielectric substrate on the yoz plane at (a) f=3.1GHz, (b) f=6.5GHz, and (c) f=13.5GHz is shown.

[0020] Figure 9 The power density distribution of the three-dimensional multilayer metamaterial of the present invention at f=3.1GHz is shown in (a) TE polarized incident and (b) TM polarized incident. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and modifications without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Combination Figure 1 A three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and composite along the propagation direction is disclosed. The structure of the absorbing metamaterial, from top to bottom, consists of an upper dielectric substrate and metal patch cross grid 1, a lower dielectric substrate and metal patch cross grid 2, a dielectric substrate 3, and a metal ground plane 4. The upper dielectric substrate is larger than the lower dielectric substrate. The upper dielectric substrate and metal patch cross grid 1 are placed in a cross shape parallel to the electromagnetic wave propagation direction. On the mutually perpendicular dielectric substrate planes, there are axisymmetric dipole antennas 5 and 6 located at the center of the plane. The arrangement of the dielectric substrate and dipole antennas in the lower dielectric substrate and metal patch cross grid 2 is the same as that in the upper layer 1, and axisymmetric dipole antennas 7 and 8 with similar structures are attached. The period of the lower layer unit is half the period of the upper layer unit, and the ratio of the number of units in the upper and lower layers is 1:4. The upper dielectric substrate and metal patch cross-shaped mesh are used to achieve microwave absorption in the 2.55-8.23 GHz range, while the lower dielectric substrate and metal patch cross-shaped mesh are used to achieve microwave absorption in the 7.87-18 GHz range. By combining two self-similar three-dimensional mesh structures of different sizes, the absorption bands of both can be effectively combined, achieving bandwidth broadening of the three-dimensional microwave absorbing metamaterial. Furthermore, this invention also exhibits good polarization stability and good mechanical load-bearing capacity.

[0023] In a further embodiment, the upper dielectric substrate and the dielectric substrate of the metal patch cross grid 1 are placed parallel to the electromagnetic wave propagation direction and form a three-dimensional grid in an orthogonal manner. A first axisymmetric dipole antenna 5 and 6 are loaded at the center of the plane of each dielectric substrate, and its axis of symmetry is the electromagnetic wave propagation direction.

[0024] In a further embodiment, the lower dielectric substrate and metal patch cross grid 2 are similar in features to the upper dielectric substrate and metal patch cross grid 1, but the loaded second axisymmetric dipole antennas 7 and 8 have some structural differences.

[0025] In the above technical solution, the upper first axisymmetric dipole antennas 5 and 6 are dipole-like antenna structures with square antenna arms at both ends hollowed out and patch resistors replaced at the center port. Two pairs of patch resistors of equal value are also loaded along the lower edge of the antenna arms to extend and smooth the absorption band. The lower second axisymmetric dipole antennas 7 and 8 have a similar structure to the upper axisymmetric dipole antennas 5 and 6, except that no additional patch resistors are loaded along the lower edge of the antenna arms.

[0026] Specifically, the metal part of the dipole antenna structure is made of copper, the resistor part is a lumped patch resistor, and the back is a solid metal ground plane, which is used to achieve full absorption of transmitted electromagnetic waves.

[0027] The dielectric substrate 3 has no special electromagnetic parameter requirements; its main function is to provide mechanical support. The metal floor 4 is a single piece of metal that not only fixes the aforementioned double-layer metamaterial unit but also absorbs transmitted electromagnetic waves.

[0028] This invention employs a composite of a double-layer self-similar three-dimensional dielectric substrate and a metal patch cross-grid to achieve broadband dual-polarized electromagnetic wave absorption in the 2.55-15.79GHz range.

[0029] Example

[0030] Combination Figure 2 The designed three-dimensional metamaterial periodic unit will be made into a 10×10 full plate in practical applications.

[0031] Combination Figure 3 The period size of each unit is p=21mm, and the ratio of the number of upper and lower structures is 1:4.

[0032] Combination Figure 4The side view of the three-dimensional multilayer metamaterial unit shown indicates that the thickness of the horizontal dielectric substrate, which serves as the load-bearing element, is t1=1mm. The height of the upper dielectric substrate is h1=7.5mm, and its thickness is t2=1.5mm. The height of the lower dielectric substrate is h2=7mm, and its thickness is t3=0.5mm. Replacing the intermediate structure of the antenna structure with lumped resistors, the intermediate resistance of the upper structure is res_m1=75Ω, and the intermediate resistance of the lower structure is res_m2=150Ω. The resistors added to the lower edge of the antenna arm of the upper structure have equal resistance values: res1=res2=res3=res4=100Ω.

[0033] Combination Figure 5 The specific dimensions of the upper-layer first axisymmetric dipole antenna shown are shown in Table 1.

[0034] Table 1

[0035] parameter a1 a2 b1 b2 w1 value / mm 5.5 3.9 7 5.4 0.8 parameter l1 l2 gap1 gap2 value / mm 3 1.5 0.6 0.4

[0036] The outer width of the metal antenna arm is a1=5.5mm, the inner width is a2=3.9mm, the outer length is b1=7mm, and the inner length is b2=5.4mm; the width of the middle section metal is w1=0.8mm, the length is l1=3mm, the width of the middle section loading resistor gap is gap1=0.6mm, the distance from the opening of the loading resistor at the lower edge of the antenna arm to the axis of symmetry is l2=1.5mm, and the opening width is gap2=0.4mm.

[0037] Combination Figure 6 The specific dimensions of the lower-layer second axisymmetric dipole antenna shown are illustrated in Table 2.

[0038] Table 2

[0039] parameter a3 a4 b3 b4 w2 l3 value / mm 4 3.5 3.5 3.0 0.5 2

[0040] The outer width of the metal antenna arm is a3=4mm, the inner width is a4=3.5mm, the outer length is b3=3.5mm, and the inner length is b4=3.0mm; the width of the middle metal section is w2=0.5mm, the length is l3=2mm, and the width of the middle loading resistor gap is the same as the width of gap2, which is 0.4mm.

[0041] The three-dimensional multilayer absorbing metamaterial unit was simulated and analyzed in the electromagnetic simulation software CST, and the S11 reflection curve of the invented three-dimensional absorbing metamaterial under perpendicular incidence of TE polarized waves was obtained as follows: Figure 7 As shown. By Figure 7 It can be seen that the multilayer structure can achieve broadband absorption of 2.55-15.79 GHz. Separate simulation analyses of the three-dimensional cross-shaped mesh of the upper dielectric substrate and metal units, and the three-dimensional cross-shaped mesh of the lower dielectric substrate and metal units, yield their respective S11 curves, as shown below. Figure 7As shown by the dashed line, the upper structure can absorb waves in the range of 2.55-8.23 GHz when working alone, and the lower structure can absorb waves in the range of 7.87-18 GHz when working alone. When combined, they can combine the absorption bandwidth of the two.

[0042] like Figure 8 As shown in Figures (a), (b), and (c), the power density distribution at the three absorption peaks of 3.1 GHz, 6.5 GHz, and 13.5 GHz exhibits characteristics consistent with the S11 curve before structural recombination. At the first two absorption peaks, the large ohmic loss is mainly caused by the mid-range resistance of the upper structure, and the resistance at the lower edge of the antenna arm also plays a role in absorption. At the same time, there is also capacitive coupling between adjacent units. As the frequency increases, the role of the lower structure gradually becomes dominant. At the third absorption peak, the mid-range resistance of the lower layer plays the main role in loss.

[0043] Combination Figure 9 Figures (a) and (b) show that the three-dimensional multilayer absorbing metamaterials exhibit good dual-polarization absorption performance by absorbing waves in the yoz plane and xoz plane when TE-polarized and TM-polarized waves are incident.

[0044] In summary, this invention proposes a three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and composited along the propagation direction. The metamaterial structure shown, from top to bottom, consists of an upper dielectric substrate and a metal patch cross-shaped grid, a lower dielectric substrate and a metal patch cross-shaped grid, a dielectric substrate, and a metal ground plane. The dielectric substrates are placed in a cross-shaped arrangement along the propagation direction, and a dipole-like antenna structure with lumped resistance at the center of the dielectric substrate is loaded. The period of the lower layer elements is half that of the upper layer elements, and the ratio of the number of elements in the upper to lower layers is 1:4. By compositing two self-similar three-dimensional grid structures of different sizes, the absorption bands of both can be effectively combined, achieving bandwidth broadening of the three-dimensional absorbing metamaterial. Furthermore, this invention also exhibits good polarization stability and good mechanical load-bearing performance.

[0045] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. In other words, any simple equivalent transformations and modifications made based on the claims and description of the present invention should be considered within the scope of protection of this patent. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and composited along the propagation direction, wherein the absorbing metamaterial structure, from top to bottom, consists of an upper dielectric substrate and metal patch cross-shaped grid (1), a lower dielectric substrate and metal patch cross-shaped grid (2), a dielectric substrate (3), and a metal ground plane (4), characterized in that: The upper dielectric substrate and the metal patch cross grid (1) are placed in a cross shape parallel to the electromagnetic wave propagation direction. The dielectric substrate planes perpendicular to each other have a first axisymmetric dipole antenna located at the center of the plane. The arrangement of the dielectric substrate and the dipole antenna in the lower dielectric substrate and the metal patch cross grid (2) is the same as that of the upper layer (1). A second axisymmetric dipole antenna is attached. The period of the lower unit is 1 / 2 of the period of the upper unit. The ratio of the number of units in the upper and lower layers is 1:

4.

2. The three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and recombination along the propagation direction as described in claim 1 is characterized in that, The upper dielectric substrate and the metal patch cross grid (1) are placed parallel to the electromagnetic wave propagation direction and form a three-dimensional grid in an orthogonal manner. A first axisymmetric dipole antenna is loaded at the center of the plane of each dielectric substrate, and its axis of symmetry is the electromagnetic wave propagation direction.

3. The three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and recombination along the propagation direction as described in claim 2 is characterized in that... The upper first axisymmetric dipole antenna is a dipole-like antenna structure with square antenna arms at both ends hollowed out and patch resistors replaced at the center port; two pairs of patch resistors of equal value are also loaded on the lower edge of the antenna arms of the dipole antenna to extend and smooth the absorbing band.

4. The three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and recombination along the propagation direction as described in claim 1 is characterized in that... The difference between the lower-layer second axisymmetric dipole antenna and the upper-layer first axisymmetric dipole antenna is that no additional patch resistor is loaded on the lower side of the antenna arm.

5. The three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and recombination along the propagation direction as described in claim 1 is characterized in that, The metal parts of the first and second axisymmetric dipole antennas are made of copper, and the resistors are lumped patch resistors.

6. The three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and recombination along the propagation direction as described in claim 1 is characterized in that, The metal floor (4) is a whole metal plate used to fix the double-layer metamaterial unit and to absorb transmitted electromagnetic waves.

7. The three-dimensional multilayer absorbing metamaterial based on antenna reciprocity and recombination along the propagation direction as described in claim 1 is characterized in that, The upper dielectric substrate and metal patch cross grid (1) are used to achieve wave absorption of 2.55-8.23GHz, and the lower dielectric substrate and metal patch cross grid (2) are used to achieve wave absorption of 7.87-18GHz. By combining two sizes of self-similar three-dimensional grid structures, the wave absorption frequency bands of the two can be combined to achieve the frequency band broadening of the three-dimensional wave absorbing metamaterial.

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