A ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window

Abstract

The present invention relates to a ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window. The window core comprises a window core, which is woven from a flexible electromagnetic shielding fabric. The flexible electromagnetic shielding fabric waveguide window of the present invention has three functions of electromagnetic shielding, ventilation and natural lighting. Due to its light weight, it can be arranged on the upper part of the electromagnetic shielding tent body, providing the possibility of large-area natural ventilation and lighting for the electromagnetic shielding tent, and providing a more comfortable working environment for the staff in the tent.

Description

Technical Field

[0001] The invention relates to a ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window, belonging to the technical field of electromagnetic shielding. Background Art

[0002] The electromagnetic shielding tent is an electromagnetic shielding device made of flexible electromagnetic shielding fabric. It has the advantages of light weight, easy transportation, quick installation and withdrawal. It can be used for electromagnetic protection of field command posts. It can prevent the electronic information system of the field command post from being interfered with and damaged by enemy electromagnetic weapons, and prevent the leakage of electromagnetic information of the field command post.

[0003] In the past, electromagnetic shielding tents all used ventilation waveguide windows made of metal materials as ventilation windows. Such ventilation waveguide windows have disadvantages such as heavy weight and high cost. In addition, the connection method between the ventilation waveguide window and the electromagnetic shielding tent is complicated. The waveguide window needs to be provided with a flange, and a metal pressing frame and screws are used to fix the sleeve-shaped shielding fabric structure connected to the shielding tent on the flange. When the electromagnetic shielding tent is erected, the sleeve-shaped shielding fabric structure is rolled and connected with the shielding fabric connection structure on the shielding tent body. During the installation of the sleeve-shaped shielding structure and the erection of the shielding tent, electromagnetic leakage from the ventilation waveguide window often occurs, resulting in a decrease in the shielding efficiency of the shielding tent. It is the accessory with the highest failure rate in the electromagnetic shielding tent.

[0004] In the past, electromagnetic shielding tents all used flexible shielding skylights as lighting windows. Flexible shielding skylights use high-density metal wire mesh as shielding material, and then a layer of transparent film is laminated on both sides. This type of shielding skylight is not only very expensive, but also has a very low light transmittance. For shielding tents with high shielding efficiency, double-window overlapping skylights are required, and the light transmittance is less than 25%. The higher the shielding efficiency, the lower the light transmittance.

[0005] The traditional ventilation waveguide windows made of metal materials and the flexible shielding lighting windows based on metal wire mesh need to be assembled on site on the electromagnetic shielding tent body when setting up the electromagnetic shielding tent. When withdrawing the electromagnetic shielding tent, they need to be disassembled from the tent body and packed separately. This not only increases the time for setting up and withdrawing the electromagnetic shielding tent, but also easily causes electromagnetic leakage of the electromagnetic shielding tent, increases the failure rate, and reduces the overall shielding efficiency of the electromagnetic shielding tent. Summary of the invention

[0006] The present invention aims to provide a low-cost, light-weight, flexible shielding fabric waveguide window for ventilation and lighting.

[0007] To this end, the technical solution adopted by the present invention is: a ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window, including a window core, and the window core is woven with flexible electromagnetic shielding fabric.

[0008] Furthermore, the flexible electromagnetic shielding fabric is one of the following structural forms:

[0009] 1) comprising a silver-plated fiber base fabric, wherein a nickel-plated layer and a copper-plated layer are sequentially arranged on both sides of the silver-plated fiber base fabric from inside to outside to form the flexible electromagnetic shielding fabric;

[0010] 2) Stainless steel conductive wire and high-strength polyester fiber are blended to form yarn, and then the yarn is woven to form the flexible electromagnetic shielding fabric;

[0011] 3) Graphene is coated on the surface of the fabric to form the flexible electromagnetic shielding fabric.

[0012] Furthermore, in the flexible electromagnetic shielding fabric of the first type: the silver-plated fiber base cloth is a high-strength polyester fiber cloth plated with nano-silver, and a nickel alloy layer is provided outside the copper-plated layer.

[0013] The flexible waveguide window adopts nano-alloy electromagnetic shielding fabric. First, nano-silver is plated on high-strength polyester fiber, and the silver-plated fiber is used to weave the electromagnetic shielding cloth substrate. Since the silver-plated fiber has good continuous conductivity, the woven substrate has good shielding effectiveness in both high and low frequency bands. Then, nickel, copper and nickel alloy layers are plated from the inside to the outside on the woven substrate. The inner nickel-plated layer has a higher magnetic permeability, which can improve the shielding effectiveness of the shielding fabric in the low frequency band. The middle copper-plated layer has a higher electrical conductivity, which can effectively improve the shielding effectiveness in the high frequency band. The outer nickel alloy coating can not only further improve the shielding effectiveness, but also enhance the firmness and antioxidant properties of the coating. The weight of a single-layer shielding fabric is less than 150 g / m2, and the shielding cloth effectiveness can reach more than 60dB.

[0014] Furthermore, the window core is formed by sewing the fabric with stainless steel sewing thread to form cutoff waveguides with various cross-sectional forms.

[0015] Furthermore, the cross-section of the waveguide tube may be one of square, rhombus, hexagon, circle and triangle.

[0016] Further, it also includes a flexible shielding fabric assembly connector and a frame;

[0017] One end of the flexible shielding fabric assembly connector connects the window core to the frame, and the other end of the flexible shielding fabric assembly connector is directly connected to the tent body or connected through an intermediate piece.

[0018] Further, the flexible shielding fabric assembly connector is composed of a double layer of shielding fabric;

[0019] The assembly connector is sewn into one with the window core by stainless steel sewing thread, wherein the shielding fabric close to the frame is fixedly connected to the frame to form an integrated structure, and the shielding fabric of the frame is directly connected to the tent body or connected to the tent body through an intermediate piece.

[0020] Furthermore, a layer of transparent windshield curtain is provided, and the transparent windshield curtain can cover the window core when it is lowered.

[0021] Furthermore, the window core is designed according to the following process:

[0022] 1) Test the electromagnetic shielding effectiveness S of the shielding fabric used to sew the waveguide window core Eb ;

[0023] 2) Calculate the waveguide cutoff frequency correction coefficient b1 by formula (2);

[0024] 3) Determine the cut-off frequency fc of the waveguide, which is approximately 1.2 times the highest operating frequency fm of the shielding tent;

[0025] 4) Calculate the corresponding cross-sectional length data of waveguides with different cross-sections using formula (1);

[0026] 5) Calculate the electromagnetic shielding effectiveness correction factor b2 using formula (4);

[0027] 6) Determine the electromagnetic shielding effectiveness S of the electromagnetic shielding fabric waveguide window E , and calculate the length L of the waveguide by formula (3);

[0028] 7) The corresponding cross-sectional length data of the cut-off waveguide, the length L and the measured shielding effectiveness S of the shielding fabric obtained by approximate calculation according to the above method Eb ,Use electromagnetic calculation simulation software to calculate the shielding effectiveness of the electromagnetic shielding fabric waveguide window. If the index requirements are met, the design is completed; if the index requirements are not met, the cutoff waveguide section length is reduced, the waveguide length is increased, and the electromagnetic calculation simulation software is used again to calculate the shielding effectiveness of the waveguide window. If the index requirements are met, the design is completed, otherwise the process is continued until the design index requirements are met;

[0029] The above formulas are explained as follows:

[0030] The approximate calculation formula for the waveguide cutoff frequency is:

[0031] (Hz) a is the side length of the square cross-section waveguide (cm);

[0032] (Hz) b is the length of the long side of the rectangular cross-section waveguide (cm);

[0033] (Hz) c is the long diagonal length of the rhombus cross-section waveguide (cm);

[0034] (Hz) w is the diameter of the circumscribed circle of the waveguide with a regular hexagonal cross section (cm);

[0035] Formula (1);

[0036] In formula (1), fc is the waveguide cutoff frequency (Hz), b1 is the cutoff frequency correction coefficient, and the approximate calculation formula of b1 is:

[0037] Formula (2);

[0038] In formula (2), S Eb The electromagnetic shielding effectiveness of the shielding fabric strips used to sew the waveguide window core;

[0039] The approximate calculation formula for the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window is:

[0040] (dB) Formula (3);

[0041] In formula (3), S E is the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window (dB), l is the waveguide length (cm), f is the frequency of the electromagnetic wave (Hz), b2 is the electromagnetic shielding effectiveness correction factor, and the approximate calculation formula of b2 is:

[0042] Formula (4).

[0043] The advantages of the present invention are: for the first time, a technical solution is proposed to use flexible electromagnetic shielding fabric to make an integrated electromagnetic shielding ventilation waveguide window and a lighting window that can be used in an electromagnetic shielding tent; an approximate calculation formula for the cutoff frequency of a shielding fabric waveguide tube and an approximate calculation formula for the electromagnetic shielding effectiveness of a shielding fabric waveguide window are proposed; a rapid design method for a shielding fabric waveguide window using a mixture of approximate calculation and computer simulation optimization is proposed; and the invented ventilation and light-transmitting flexible electromagnetic shielding fabric waveguide window has the following advantages:

[0044] 1. All of them are made of shielding fabrics, with simple process and low cost. Compared with the metal ventilation waveguide windows and metal wire mesh flexible lighting windows used in the electromagnetic shielding tents currently in service in our army, the cost is reduced several times.

[0045] 2. The flexible electromagnetic shielding fabric waveguide window can be directly sewn onto the electromagnetic shielding tent body, which not only effectively shortens the erection and withdrawal time, but also greatly reduces the difficulty of operation for non-professionals and the resulting failure rate of electromagnetic leakage of the electromagnetic shielding tent.

[0046] 3. The weight of the main accessories of the electromagnetic shielding tent is greatly reduced. At the same time, the flexible structure is convenient for packaging and transportation, which provides favorable conditions for the packaging, storage and transportation of the electromagnetic shielding tent.

[0047] The flexible electromagnetic shielding fabric waveguide window of the present invention has three functions of electromagnetic shielding, ventilation and natural lighting. Due to its light weight, it can be arranged on the upper part of the electromagnetic shielding tent body, making it possible to provide large-area natural ventilation and lighting for the electromagnetic shielding tent, and providing a more comfortable working environment for the staff in the tent. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the waveguide window structure of the present invention.

[0049] Figure 2 It is a schematic diagram of the structure of the waveguide window core (square cross section) of the present invention.

[0050] Figure 3 This is a schematic diagram of the structure of the first type of fabric of the present invention. DETAILED DESCRIPTION

[0051] A ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window comprises a flexible electromagnetic shielding fabric waveguide window core, a flexible shielding fabric assembly connector, a sleeve-shaped canopy connector and a plastic shaping frame. Figure 1 As shown, the specific technical scheme is as follows: the flexible electromagnetic shielding fabric waveguide window core is sewn into a cutoff waveguide array structure by using shielding fabric strips, and the waveguide cross section can be square / rhombus / hexagon / circle / triangle and other unequal sides (taking a regular side as an example below), and its side length is designed according to the cutoff frequency requirements, and the waveguide length is designed according to the shielding effectiveness index requirements. The flexible shielding fabric assembly connector is composed of a double-layer shielding fabric, and the double-layer shielding fabric and the flexible electromagnetic shielding fabric waveguide window core are sewn together by 100% stainless steel sewing thread. The shielding fabric close to the plastic shaping frame is fixed to the shaping frame, and the flexible electromagnetic shielding fabric waveguide window core can be stretched and formed into a rectangular waveguide array. On the one hand, according to the cutoff characteristics of the waveguide, electromagnetic waves below the specified frequency are quickly attenuated, and on the other hand, the ventilation performance and light transmittance of the waveguide window can be improved. The other layer of shielding fabric can be directly sewn on the shielding tent body, or can be connected to the shielding tent body by rolling through the sleeve-shaped tent body connector sewn thereon. The plastic shaping frame is a rectangular frame made of plastic, which plays the role of fixing the waveguide window core.

[0052] The flexible electromagnetic shielding fabric waveguide window core is made of shielding fabric strips. The structure is as follows Figure 1As shown, the structure (1) of the shielding fabric waveguide window core is a square cross-section cutoff waveguide array, which is sewn with 100% stainless steel shielding wire (2), and the four sides of each cutoff waveguide tube (3) are all high-conductivity shielding fabrics. According to the results of electromagnetic theory and computer simulation, when the electromagnetic wave frequency is lower than the cutoff frequency of the cutoff waveguide tube (3), the electromagnetic wave decays rapidly along the length direction of the waveguide tube, thus generating a shielding effect on the electromagnetic wave. The cutoff frequency of the cutoff waveguide tube and the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window are calculated based on the computer simulation results and fitted with a large amount of actual test data.

[0053] The approximate calculation formula for the waveguide cutoff frequency is:

[0054] (Hz) a is the side length of the square cross-section waveguide (cm);

[0055] (Hz) b is the length of the long side of the rectangular cross-section waveguide (cm);

[0056] (Hz) c is the long diagonal length of the rhombus cross-section waveguide (cm);

[0057] (Hz) w is the diameter of the circumscribed circle of the waveguide with a regular hexagonal cross section (cm);

[0058] Formula (1);

[0059] In formula (1), fc is the waveguide cutoff frequency (Hz), b1 is the cutoff frequency correction coefficient, and the approximate calculation formula of b1 is:

[0060] Formula (2);

[0061] In formula (2), S Eb The electromagnetic shielding effectiveness of the shielding fabric strips used to sew the waveguide window core;

[0062] The approximate calculation formula for the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window is:

[0063] (dB) Formula (3);

[0064] In formula (3), S E is the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window (dB), l is the waveguide length (cm), f is the frequency of the electromagnetic wave (Hz), b2 is the electromagnetic shielding effectiveness correction factor, and the approximate calculation formula of b2 is:

[0065] Formula (4).

[0066] The design method of the flexible electromagnetic shielding fabric waveguide window core is as follows:

[0067] 1) Test the electromagnetic shielding effectiveness S of the shielding fabric used to sew the waveguide window core Eb ;

[0068] 2) Calculate the waveguide cutoff frequency correction coefficient b1 by formula (2);

[0069] 3) Determine the cut-off frequency fc of the waveguide, which is approximately 1.2 times the highest operating frequency fm of the shielding tent;

[0070] 4) Calculate the corresponding cross-sectional length data of waveguides with different cross-sections using formula (1);

[0071] 5) Calculate the electromagnetic shielding effectiveness correction factor b2 using formula (4);

[0072] 6) Determine the electromagnetic shielding effectiveness S of the electromagnetic shielding fabric waveguide window E , and calculate the length L of the waveguide by formula (3);

[0073] 7) The corresponding cross-sectional length data of the cut-off waveguide, the length L and the measured shielding effectiveness S of the shielding fabric obtained by approximate calculation according to the above method Eb , the shielding effectiveness of the electromagnetic shielding fabric waveguide window is calculated using electromagnetic calculation simulation software. If the index requirements are met, the design is completed; if the index requirements are not met, the cutoff waveguide section length is reduced and the waveguide tube length is increased. The electromagnetic calculation simulation software is used again to calculate the shielding effectiveness of the waveguide window. If the index requirements are met, the design is completed, otherwise the process is continued until the design index requirements are met.

Claims

1. A ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window, characterized in that: It includes a window core, which is woven with a flexible electromagnetic shielding fabric; A layer of transparent windshield curtain is also provided, and the transparent windshield curtain can cover the window core when it is lowered; The window core is designed according to the following process: 1) Test the electromagnetic shielding effectiveness S of the shielding fabric used to sew the waveguide window core Eb ; 2) Calculate the waveguide cutoff frequency correction coefficient b1 by formula (2); 3) Determine the cut-off frequency fc of the waveguide, which is approximately 1.2 times the highest operating frequency fm of the shielding tent; 4) Calculate the corresponding cross-sectional length data of waveguides with different cross-sections using formula (1); 5) Calculate the electromagnetic shielding effectiveness correction factor b2 using formula (4); 6) Determine the electromagnetic shielding effectiveness S of the electromagnetic shielding fabric waveguide window E , and calculate the length l of the waveguide by formula (3); 7) The corresponding cross-sectional length data of the cut-off waveguide, length l and the measured shielding effectiveness S of the shielding fabric obtained by approximate calculation according to the above process Eb ,Use electromagnetic calculation simulation software to calculate the shielding effectiveness of the electromagnetic shielding fabric waveguide window. If the index requirements are met, the design is completed; if the index requirements are not met, the cutoff waveguide section length is reduced, the waveguide length is increased, and the electromagnetic calculation simulation software is used again to calculate the shielding effectiveness of the waveguide window. If the index requirements are met, the design is completed, otherwise the process is continued until the design index requirements are met; The above formulas are explained as follows: The approximate calculation formula for the waveguide cutoff frequency is: (Hz) Formula (1); a is the side length of the square cross-section waveguide (cm); (Hz) Formula (1); b is the length of the long side of the rectangular cross-section waveguide (cm); (Hz) Formula (1); c is the long diagonal length of the rhombus cross-section waveguide (cm); (Hz) Formula (1); w is the diameter of the circumscribed circle of the waveguide with a regular hexagonal cross section (cm); In each equation (1): fc is the waveguide cutoff frequency (Hz), b1 is the cutoff frequency correction coefficient, and the approximate calculation formula of b1 is: Formula (2); In formula (2), S Eb The electromagnetic shielding effectiveness of the shielding fabric strips used to sew the waveguide window core; The approximate calculation formula for the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window is: (dB) Formula (3); In formula (3), S E is the electromagnetic shielding effectiveness of the electromagnetic shielding fabric waveguide window (dB), l is the waveguide length (cm), f is the frequency of the electromagnetic wave (Hz), b2 is the electromagnetic shielding effectiveness correction factor, and the approximate calculation formula of b2 is: Formula (4).

2. The ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window according to claim 1, characterized in that: The flexible electromagnetic shielding fabric is one of the following structural forms: 1) comprising a silver-plated fiber base fabric, wherein a nickel-plated layer and a copper-plated layer are sequentially arranged on both sides of the silver-plated fiber base fabric from inside to outside to form the flexible electromagnetic shielding fabric; 2) Stainless steel conductive wire and high-strength polyester fiber are blended to form yarn, and then the yarn is woven to form the flexible electromagnetic shielding fabric; 3) Graphene is coated on the surface of the fabric to form the flexible electromagnetic shielding fabric.

3. The ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window according to claim 2, characterized in that: Among them, the flexible electromagnetic shielding fabric of the first type: the silver-plated fiber base cloth is a high-strength polyester fiber cloth plated with nano-silver, and a nickel alloy layer is arranged outside the copper-plated layer.

4. The ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window according to claim 1, characterized in that: The window core is formed by sewing the fabric with stainless steel sewing thread to form cutoff waveguides with various cross-sections.

5. The ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window according to claim 4, characterized in that: The cross-section of the waveguide tube may be one of square, rhombus, hexagon, circle and triangle.

6. The ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window according to claim 1, characterized in that: Also included are flexible shielding fabric assembly connectors and a frame; One end of the flexible shielding fabric assembly connector connects the window core to the frame, and the other end of the flexible shielding fabric assembly connector is directly connected to the tent body or connected through an intermediate piece.

7. The ventilated and light-transmitting flexible electromagnetic shielding fabric waveguide window according to claim 6, characterized in that: The flexible shielding fabric assembly connector is composed of a double layer of shielding fabric; The assembly connector is sewn into one with the window core by stainless steel sewing thread, wherein the shielding fabric close to the frame is fixedly connected to the frame to form an integral structure, and the shielding fabric away from the frame is directly connected to the tent body or connected through an intermediate piece.

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