Cement-based electromagnetic wave-absorbing superstructure based on stranded cable structure

Abstract

The utility model provides a cement-based electromagnetic wave-absorbing superstructure based on a stranded cable structure, a substrate of the cement-based electromagnetic wave-absorbing superstructure is made of a cement-based flat plate material, and a cement-based stranded cable periodic structure is arranged on the surface of the cement-based electromagnetic wave-absorbing superstructure. The cement-based electromagnetic wave-absorbing superstructure can achieve the technical index of excellent wave-absorbing performance, has the characteristics of wide frequency band and wide-angle wave-absorbing, and can achieve the effects that the average reflectivity in the microwave band of 1-40GHz is less than-15dB (the absorptivity is 96.8%), the effective absorption bandwidth of-10dB exceeds 60% of the total bandwidth, and the effective absorption bandwidth of-10dB exceeds 60% of the total bandwidth. And the average absorptivity under the large incidence angle of 60 degrees is not less than the average absorptivity under the normal incidence angle of 0 degree.

Description

Technical Field

[0001] The utility model relates to a cement-based electromagnetic wave absorbing superstructure based on a cable twisting structure, which has the characteristics of wide-band and wide-angle electromagnetic wave absorption. Background Technique

[0002] As the building material with the largest consumption and the widest application in the world today, cement-based materials play a crucial role in constructing modern infrastructure. With the increasingly in-depth application of electronic information technology in various fields, improving the electromagnetic wave absorption and stealth ability of building structures has become a new urgent need. For example, enhancing the survival ability and information interception ability of security projects, as well as a series of problems such as information secrecy, anti-electromagnetic interference, and human electromagnetic radiation protection faced in contemporary society under the wide application of 5G and 6G communication technologies, all highlight the importance of developing electromagnetic wave absorption technology in the field of civil architecture. However, traditional building structures generally use shelters or metal shields to achieve electromagnetic wave absorption and stealth, facing challenges such as the separation of wave absorption function and structure, limited application scenarios, and high operation and maintenance costs. Developing and researching new cement-based wave absorbing materials with high wave absorption performance and structure-function integration has important value for ensuring public safety, optimizing the electromagnetic environment, and improving the quality of engineering construction. Content of the Utility Model

[0003] The real electromagnetic environment has the characteristics of different incident frequency bands and incident angles. The utility model integrates superstructure elements and cement-based substrates to provide a cement-based electromagnetic wave absorbing superstructure based on a cable twisting structure, aiming to greatly improve the wide-band wave absorption performance and wide-angle absorption performance of the cement-based material structure.

[0004] For this reason, the utility model adopts the following technical solutions:

[0005] A cement-based electromagnetic wave absorbing superstructure based on a cable twisting structure, characterized in that the base of the cement-based electromagnetic wave absorbing superstructure is a cement-based flat material, and a periodic structure of cement-based cable twists is arranged on the surface of the cement-based electromagnetic wave absorbing superstructure, which has the characteristics of wide-band and wide-angle wave absorption.

[0006] On the basis of adopting the above technical solutions, the utility model can also adopt the following further technical solutions, or use a combination of these further technical solutions:

[0007] The periodic structure of the cement-based cable twists is composed of cement-based cable twists as basic units and arranged in a periodic structure. The period size T of the periodic structure is determined by the following formula:

[0008] T≥c / 2f L (1)

[0009] Wherein, c is the speed of light, f Lis the minimum value of the designed working frequency band of the cement-based electromagnetic wave absorbing superstructure.

[0010] The outer diameter D of the cement-based stranded cable rope <T, which consists of an inner core and an outer layer. The inner core is a conductive stranded cable with a diameter d rope and the outer layer is wrapped with a dielectric thin shell of cement-based material with a thickness of t shell The dielectric thin shell of cement-based material, D rope = d rope + 2t shell .

[0011] The inner conductive stranded cable is composed of two or more bundles of conductive fibers spirally wound. The diameter d of a single bundle of conductive fibers bundle is determined by the following formula:

[0012] d bundle ≤ c / 2f H (2)

[0013] where c is the speed of light and f H is the maximum value of the designed working frequency band of the cement-based electromagnetic wave absorbing superstructure.

[0014] The thickness t of the dielectric thin shell of cement-based material shell is determined by the following formula:

[0015]

[0016] where ε r and μ r are the relative permittivity and relative permeability of the cement-based material respectively.

[0017] The arrangement methods of the basic units include winding, weaving, array, etc.

[0018] The cement-based electromagnetic wave absorbing superstructure of the present utility model can achieve excellent technical indicators of wave absorption performance, has the characteristics of wide frequency band and wide-angle wave absorption, and can reach: the average reflectivity is less than -15 dB (absorption rate 96.8%) in the 1-40 GHz microwave band, the -10 dB effective absorption bandwidth exceeds 60% of the total bandwidth, and the average absorption rate at a large incident angle of 60° is not less than the average absorption rate at normal incidence of 0°. Description of the Drawings

[0019] Figure 1 is a schematic diagram of the preparation process of the cement-based electromagnetic wave absorbing superstructure of the present utility model;

[0020] Figure 2 is a figure of the final product of the cement-based electromagnetic wave absorbing superstructure based on the stranded cable structure with a partial enlargement;

[0021] Figure 3This is the measured result of the wave absorption performance of the embodiment of the present utility model under wide-angle incident waves. Specific embodiments

[0022] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. It should be understood that the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model. The unstated implementation conditions are usually those in conventional experiments.

[0023] Refer to Figure 1 , the effective working frequency band of the designed cement-based electromagnetic wave absorbing superstructure in this embodiment is 8 - 40 GHz (the working bandwidth reaches 32 GHz). The cement-based cables 1 on the surface are arranged in a grid pattern, with a period T = 24 mm, that is, the center distance between adjacent cement-based cables 1 is 24 mm. The cement-based cable 1 is composed of a carbon fiber cable 11 and a cement-based dielectric thin shell 12 coated thereon. Among them, the carbon fiber cable 11 is formed by helically winding three carbon fiber bundles, the outer diameter of the cable is 5 mm, and the thickness of the cement-based dielectric thin shell 12 is 1 mm. The base of the cement-based electromagnetic wave absorbing superstructure is a cement-based flat plate 2 with a thickness of 25 mm. The raw materials of the cement-based dielectric thin shell 12 and the cement-based flat plate 2 of the cement-based electromagnetic wave absorbing superstructure are both engineering cement-based materials (ECC) added with PVA fibers.

[0024] The wave absorption performance of the cement-based electromagnetic wave absorbing superstructure in this embodiment is represented by the reflectivity. The reflectivity of the specimen at different incident angles (0°, 15°, 30°, 45°, 60°) in the range of 1 - 40 GHz is measured by the bow method, as Figure 3 shown. The specific wave absorption indicators are as follows: in the 1 - 40 GHz microwave band, the average reflectivities of this embodiment at incident angles of 0°, 15°, 30°, 45°, and 60° are all lower than -15 dB, which are -16.2 dB, -16.6 dB, -17.7 dB, -18.8 dB, and 20.0 dB respectively, indicating that the average absorption rates of this embodiment at incident angles of 15°, 30°, 45°, and 60° are not less than the average absorption rate at normal incidence of 0°; the -10 dB effective absorption bandwidth of the embodiment at different incident angles is between 28.7 - 32.7 dB (occupying 73.5% - 84.0% of the total bandwidth), all exceeding 60% of the total bandwidth. It fully meets the required technical indicators

[0025] The above has made a detailed description of the present utility model. The above-described embodiments are only the preferred embodiments of the present utility model, which are used to help understand the method and its core idea of the present utility model. The purpose is to enable those skilled in this field to understand the content of the present utility model and implement it accordingly, and it cannot be used to limit the protection scope of the present utility model. Any modification, equivalent change or improvement made according to the spirit and essence of the present utility model shall be covered within the protection scope of the present utility model.

Claims

1. A cement-based electromagnetic wave absorbing superstructure based on a twisted cable structure, characterized in that: The base of the cement-based electromagnetic wave absorbing superstructure is a cement-based flat plate material. The surface of the cement-based electromagnetic wave absorbing superstructure is arranged with a cement-based twisted cable periodic structure. The mud-based twisted cable is composed of an inner core and an outer layer. The inner core has a diameter d rope Conductive stranded cable, the outer layer thickness is t shell Cement-based dielectric shell.

2. The cement-based electromagnetic absorbing superstructure according to claim 1, characterized in that: The cement-based twisted cable periodic structure is composed of cement-based twisted cables as basic units, arranged into a periodic structure, and the periodic size T of the periodic structure is determined by the following formula: <h2 style=";text-align:left;direction:ltr">T≥c / 2f<h2 style=";text-align:left;direction:ltr"> L <h2 style=";text-align:left;direction:ltr"> (1) Where c is the speed of light, f L The lowest value of the designed working frequency band of the cement-based electromagnetic absorbing superstructure.

3. The cement-based electromagnetic absorbing superstructure according to claim 1, characterized in that: The outer diameter D of the cement-based stranded cable rope <T,D rope =d rope +2t shell .

4. The cement-based electromagnetic absorbing superstructure according to claim 3, characterized in that: The inner conductive stranded cable is composed of two or more bundles of conductive fiber bundles spirally wound together, and the diameter of a single bundle of conductive fiber is d bundle Determined by the following formula: <h2 style=";text-align:left;direction:ltr">d<h2 style=";text-align:left;direction:ltr"> bundle <h2 style=";text-align:left;direction:ltr"> ≤c / 2f<h2 style=";text-align:left;direction:ltr"> H <h2 style=";text-align:left;direction:ltr"> (2) Where c is the speed of light, f H It is the highest value of the designed working frequency band of the cement-based electromagnetic absorbing superstructure.

5. The cement-based electromagnetic absorbing superstructure according to claim 3, characterized in that The thickness of the dielectric shell of cement-based material is t shell Determined by the following formula: Among them, ε r and μ r are the relative permittivity and relative magnetic permeability of cement-based materials, respectively.

6. The cement-based electromagnetic absorbing superstructure according to claim 2, characterized in that: The basic unit arrangement methods include winding, weaving, and array.

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