Heterogeneous honeycomb wave-absorbing structure

Abstract

The invention relates to a heterogeneous honeycomb wave-absorbing structure, and belongs to the field of stealth materials. The structure is composed of a plurality of hexagonal honeycomb units comprising a plurality of different electromagnetic materials, the incident direction of electromagnetic waves mainly aims at radial incidence, large effective depth exists in the direction, and the structural layer is in uneven periodic distribution. The propagation path of electromagnetic waves in the structure is expanded, multiple reflection is easier to occur, and absorption of the electromagnetic waves is facilitated; the heterogeneous honeycomb wave-absorbing structure is divided into four layers in the radial direction, and the dielectric constant of each layer of absorbing material is in gradient change on the whole, so that the heterogeneous honeycomb wave-absorbing structure has a better impedance matching characteristic; according to the design method, the particle swarm optimization algorithm is utilized to optimize the wave-absorbing material in the optimization layer, so that the degree of freedom of the honeycomb wave-absorbing structure is increased, and the advantage of radial length is fully utilized. The heterogeneous honeycomb wave-absorbing structure provided by the invention meets impedance matching, has broadband wave-absorbing performance, and can realize good absorption of 2-18GHz electromagnetic waves, so that the heterogeneous honeycomb wave-absorbing structure has greater application potential in related fields.

Description

Technical Field

[0001] The invention relates to the technical field of stealth materials, and specifically designs a heterogeneous honeycomb wave-absorbing structure. Background Art

[0002] With the rapid development of science and technology, advanced detection technology has reached the level of high reliability and high resolution, which has brought challenges such as low radar cross section and high detection sensitivity to the survivability of aircraft and other equipment. In order to improve the survivability, penetration capability and deep strike capability of aircraft and other aviation equipment, strengthening the low detectability of aircraft has become one of the most important development directions of advanced air equipment. Stealth technology can be divided into visible light stealth, radar stealth, infrared stealth and laser stealth according to the corresponding detection means, and radar detection technology based on electromagnetic signals is currently the most important means of long-distance detection. Therefore, radar stealth is the most important research direction of current stealth technology.

[0003] The absorbing materials used for radar stealth can be divided into coating absorbing materials and structural absorbing materials according to the molding process and load-bearing capacity. The honeycomb absorbing structure is a kind of structural absorbing material. It has a highly ordered geometric form, which can provide multiple reflection and refraction opportunities, increase the propagation path length of electromagnetic waves inside the material, and thus enhance the absorption effect. In addition, the gradual decrease of honeycomb density from the inside to the outside can cause electromagnetic waves to produce multiple reflections and refractions in the material, which helps to improve the absorbing performance. The honeycomb absorbing structure has many structural and performance advantages. Its hexagonal structure not only reduces the weight of the honeycomb absorbing structure, but also gives it good load-bearing capacity, thermal anisotropy and mechanical properties. Therefore, the design of high-performance honeycomb absorbing structures has become one of the key links in the development of today's radar stealth technology.

[0004] Existing honeycomb absorbing structures are usually made of lossless fiberboard or aramid paper as the honeycomb matrix, which is then filled or impregnated with lossy absorbing materials. However, due to the limitations of the absorbing materials, a single honeycomb is not very effective in improving the radar wave impedance matching characteristics, and the absorbing performance is difficult to meet the requirements. Therefore, there is an urgent need for a honeycomb absorbing structure with better absorbing performance. Summary of the invention

[0005] In view of one or more technical problems existing in the prior art, the present invention provides a heterogeneous cellular absorbing structure. The heterogeneous cellular absorbing structure of the present invention satisfies impedance matching and has broadband absorbing performance.

[0006] A heterogeneous honeycomb absorbing structure, characterized in that the heterogeneous honeycomb absorbing structure is composed of a plurality of hexagonal honeycomb units including a plurality of different electromagnetic materials; the electromagnetic materials are heterogeneously distributed in the honeycomb structure, and the heterogeneous honeycomb structure is divided into four layers with the help of the Smith chart and transmission line theory; the electromagnetic material includes a substrate and an absorption layer; the absorption layer includes three absorbing materials with different electromagnetic properties; the three materials are electrical material, magnetic material and air; the incident direction of the electromagnetic wave of the structure is radial incidence.

[0007] Optionally, from the perspective of electromagnetic theory, analyze how the dielectric constant and magnetic permeability of the material affect the loss characteristics of the incident electromagnetic wave. At the same time, consider factors such as honeycomb aperture, matrix thickness, and absorption layer thickness, and comprehensively consider practical applications, simulations, and material properties. Sorting out the dielectric constants and magnetic permeabilities of various materials, and comparing their loss tangents, determine the structural parameters of the heterogeneous honeycomb absorbing structure, and the electromagnetic parameters of the electrical and magnetic materials.

[0008] Optionally, with the help of Smith chart and transmission line theory analysis, the heterogeneous honeycomb structure is divided into four layers. The first layer is air, which plays a buffering and adapting role; the second layer uses magnetic materials to cooperate with air to achieve impedance matching and reduce reflection; the fourth layer uses electrical materials to absorb high-frequency electromagnetic waves by using their high-frequency polarization relaxation loss characteristics and high dielectric loss characteristics; the third layer in the middle is used as an optimization layer, which uses a random combination of three absorbing materials to adjust the electromagnetic characteristics and improve the overall absorbing performance.

[0009] Optionally, the three-dimensional model can be equivalent to a two-dimensional model for simulation design.

[0010] Optionally, the third optimization layer utilizes an optimization algorithm to optimize the structure.

[0011] The beneficial effects of the present invention are as follows: a heterogeneous honeycomb absorbing structure of the present invention is composed of a plurality of hexagonal honeycomb units including a plurality of different electromagnetic materials, and the incident direction of the electromagnetic wave is mainly aimed at radial incidence. In this direction, there is a large effective depth and the structural layer presents an uneven periodic distribution, which expands the propagation path of the electromagnetic wave inside the structure and is more prone to multiple reflections, which is beneficial to the absorption of electromagnetic waves; the heterogeneous honeycomb absorbing structure is divided into four layers in the radial direction, and the dielectric constant of each layer of absorbing material changes gradiently as a whole, so that the heterogeneous honeycomb absorbing structure has better impedance matching characteristics; in the design method, the particle swarm optimization algorithm is used to optimize the absorbing material in the optimization layer, increase the degree of freedom of the honeycomb absorbing structure, and make full use of the advantages in radial length. The heterogeneous honeycomb absorbing structure of the present invention meets impedance matching and has broadband absorbing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the purpose, technical solutions and advantages of the present invention, the invention patent will be described in detail below in conjunction with the accompanying drawings, wherein:

[0013] Figure 1 A three-dimensional and two-dimensional image of a heterogeneous honeycomb absorbing structure.

[0014] Figure 2 This is a schematic diagram of the size parameters of a heterogeneous honeycomb absorbing structure of the present invention.

[0015] Figure 3 This is a four-layer structural optimization diagram of a heterogeneous honeycomb absorbing structure of the present invention.

[0016] Figure 4 This is a layout diagram of the absorbing material of a heterogeneous honeycomb absorbing structure of the present invention.

[0017] Figure 5 This is the L downward reflection loss curve of a heterogeneous honeycomb absorbing structure proposed in the present invention.

[0018] Figure 6 This is a W-down reflection loss curve of a heterogeneous honeycomb absorbing structure proposed in the present invention.

[0019] Figure 7 This is a curve diagram of electromagnetic parameters of absorbing materials. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "due north", "due south", "due east", "due west", "southeast", "northeast", "southwest", "northeast", "southwest", "northwest", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0022] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0023] Combine the following Figure 1-Figure 7 The heterogeneous honeycomb absorbing structure designed in this patent is further described in detail.

[0024] First, the honeycomb absorbing structure usually presents a unique three-dimensional structure. Due to its three-dimensional characteristics, the incident direction of the electromagnetic wave can be mainly divided into axial and radial directions. In the present invention, the focus is on the radial incident situation of the electromagnetic wave. Figure 1 As shown in the figure, when the electromagnetic wave is incident radially on the honeycomb absorbing structure, it has significant advantages. In the radial direction, the honeycomb structure has a large effective depth, and this feature greatly expands the propagation path of the electromagnetic wave in the honeycomb structure. At the same time, the structural layer in this direction presents an uneven periodic distribution. This special structure not only further expands the propagation path of the electromagnetic wave inside the structure, but also makes the electromagnetic wave more prone to multiple reflections. The process of multiple reflections can effectively dissipate the energy of the electromagnetic wave step by step, which is greatly beneficial to the absorption of electromagnetic waves. In addition, when the electromagnetic wave is incident radially, the lengths of the other two directions of the honeycomb absorbing structure can generally be regarded as infinite. Based on this feature, the original three-dimensional honeycomb structure can be equivalently converted into a two-dimensional planar honeycomb structure for simulation design, such as Figure 1 As shown in the two-dimensional diagram. Due to radial incidence, the honeycomb structure will show different results in different polarization directions. The polarization direction of the honeycomb height is defined as the L direction, and the other direction is defined as the W direction, as shown in Figure 1 As shown in the three-dimensional figure.

[0025] Next, from the perspective of electromagnetic theory, we analyze how the dielectric constant and magnetic permeability of materials affect the loss characteristics of incident electromagnetic waves. At the same time, we consider factors such as honeycomb aperture, matrix thickness, and absorption layer thickness, and conduct a comprehensive analysis from the perspectives of practical application, simulation, and material properties. We sort out the dielectric constants and magnetic permeabilities of various materials, and compare their loss tangents, and then select an electrical material A and a magnetic material B. Their electromagnetic parameters are as follows: Figure 2 The specific structural parameters and dimensions of the honeycomb absorbing structure are finally obtained (in mm): t=0.1, d=0.1, r=2.75, and the heterogeneous honeycomb absorbing structure is composed of 4 rows and 3 columns with a total of 12 honeycomb units.

[0026] Afterwards, with the help of Smith chart and transmission line theory analysis, the heterogeneous honeycomb structure is divided into four layers. The first layer is air, which plays a buffering and adapting role; the second layer uses magnetic materials to cooperate with air to achieve impedance matching and reduce reflection; the fourth layer uses electrified materials to absorb high-frequency electromagnetic waves by using their high-frequency polarization relaxation loss characteristics and high dielectric loss characteristics; the third layer in the middle is used as an optimization layer, which uses a random combination of three absorbing materials to adjust the electromagnetic characteristics and improve the overall absorbing performance.

[0027] Next, the particle swarm algorithm is used to optimize the third layer structure: first determine the L-direction and W-direction reflection loss as the fitness function to reflect the wave absorption performance; then use MATLAB to call COMSOL to build a two-dimensional honeycomb model, and encode the corresponding structure and sequence according to the material and number of honeycombs; then write a MATLAB program according to the algorithm flow, set the number of iterations for simulation optimization, and complete the iteration or meet the standard. If there are multiple coding sequences that meet the requirements after optimization, according to their relationship with the structure, compare them with the three-dimensional model simulation in HFSS, and select Figure 5 The optimal heterogeneous honeycomb absorbing structure is shown.

[0028] Finally, the final design structure obtained through the above process is compared with the structure constructed using traditional single absorbent material. Figure 6 This is the comparison chart of L-direction reflection loss curve. Figure 7 It is a comparison of the W-direction reflection loss curve. When the electromagnetic wave is incident radially, all absorbing materials are set as electrical materials to obtain curve I, and all absorbing materials are set as magnetic materials to obtain curve II; when the electromagnetic wave is incident axially, the axial height of the honeycomb is consistent with the radial height, all absorbing materials are set as electrical materials to obtain curve III, and all absorbing materials are set as magnetic materials to obtain curve IV; curve V is the final optimized structure simulation diagram.

[0029] By comparison, it can be found that the heterogeneous cellular absorbing structure obtained by design means can achieve a reflection loss of at least -10dB or less in the frequency range of 2-18GHz when a uniform plane wave is incident vertically. Compared with the structure designed with a single absorption layer material, the heterogeneous cellular absorbing structure shows a better overall absorption effect, and its effective absorption frequency band is wider. This advantage makes the heterogeneous cellular absorbing structure have greater application potential in related fields. For example, in technical fields such as electromagnetic protection and radar stealth, it can better meet the requirements for electromagnetic wave absorption and control, thereby improving the performance and safety of the equipment.

[0030] 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 the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A heterogeneous honeycomb absorbing structure, characterized in that: The heterogeneous honeycomb absorbing structure is composed of a plurality of hexagonal honeycomb units including a plurality of different electromagnetic materials; the electromagnetic materials are heterogeneously distributed in the honeycomb structure, and the heterogeneous honeycomb structure is divided into four layers with the help of the Smith chart and transmission line theory; the electromagnetic material includes a substrate and an absorption layer; the absorption layer includes three absorbing materials with different electromagnetic properties; the three materials are electrical material, magnetic material and air; the incident direction of the electromagnetic wave of the structure is radial incidence.

2. The heterogeneous microwave absorbing honeycomb structure according to claim 1, characterized in that: From the perspective of electromagnetic theory, the dielectric constant and magnetic permeability of materials are analyzed to determine how they affect the loss characteristics of incident electromagnetic waves. At the same time, factors such as honeycomb aperture, matrix thickness, and absorption layer thickness are considered, and a comprehensive analysis is conducted from the perspectives of practical application, simulation, and material properties. The dielectric constant and magnetic permeability of various materials are sorted out, and their loss tangents are compared to determine the structural parameters of the heterogeneous honeycomb absorbing structure, and the electromagnetic parameters of the electrical and magnetic materials.

3. The heterogeneous wave-absorbing honeycomb structure according to claim 1, characterized in that: With the help of Smith chart and transmission line theory analysis, the heterogeneous honeycomb structure is divided into four layers. The first layer is air, which plays a buffering and adapting role; The second layer uses magnetic materials, which work together with the air to achieve impedance matching and reduce reflections. The fourth layer uses electrical materials, which use their high-frequency polarization relaxation loss characteristics and high dielectric loss characteristics to absorb high-frequency electromagnetic waves. The third layer in the middle is used as an optimization layer, which uses a random combination of three absorbing materials to adjust the electromagnetic properties and improve the overall absorbing performance.

4. The heterogeneous microwave absorbing honeycomb structure according to claim 1, characterized in that: The three-dimensional model can be equivalent to a two-dimensional model for simulation design.

5. The heterogeneous microwave absorbing honeycomb structure according to claim 1, characterized in that: The particle swarm optimization algorithm is used to optimize the structure of the third optimization layer.

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