A composite shielding wall device giving consideration to electromagnetic shielding and ventilation and heat dissipation

Abstract

The application discloses a composite shielding wall device which takes into account electromagnetic shielding and ventilation and heat dissipation, comprising a metal shielding wall, a circular waveguide array 1, a circular waveguide array 2 and a plastic conduit, two groups of independent circular waveguide arrays with the same size are arranged in parallel and staggered on two opposite wall surfaces of the metal shielding wall. The circular waveguide array 1 and the circular waveguide array 2 are arranged in parallel and staggered, which is equivalent to obtaining twice the length of the transmission waveguide of a single circular waveguide and twice the cutoff waveguide loss. While enhancing the attenuation of electromagnetic wave signals, the problem of the metal shielding wall being too thick caused by the direct opposition of the two groups of circular waveguide arrays is avoided, and the space of the metal shielding wall is saved. Air flow passes through the complete straight-through air flow channel formed by the two groups of circular waveguide arrays and the plastic conduit connecting the two groups of circular waveguide arrays, realizing the air flow exchange between the inside and the outside of the electrical equipment, so that the effect of ventilation and heat dissipation is achieved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic field technology, and specifically to a composite shielding wall device that combines electromagnetic shielding with ventilation and heat dissipation. Background Technology

[0002] In today's world, with the rapid development of modern science and technology and the widespread application of various electrical and electronic products, while facilitating people's production and lives, it has also objectively made our electromagnetic environment increasingly complex and deteriorating, bringing about a series of electromagnetic compatibility (EMC) problems. The EMC issues of electrical and electronic products are receiving increasing attention from governments and manufacturers worldwide.

[0003] Currently, using enclosed metal structures for electromagnetic shielding is a crucial and commonly used EMC technique for addressing various electromagnetic compatibility (EMC) issues. However, in practical applications, due to various reasons such as ventilation, heat dissipation, and air exchange requirements, we cannot completely enclose the equipment / entity with a metal structure for electromagnetic shielding. Instead, we need to create corresponding windows / holes in the shielding structure. In this case, electromagnetic energy leakage (e.g., ...) can occur through these windows / holes. Figure 1 (As shown). According to electromagnetic field theories, the larger the size of these windows / holes, the more severe the electromagnetic leakage and the worse the electromagnetic shielding performance. To meet the electromagnetic shielding performance requirements, the size of the windows / holes must be reduced. For example, for a shielding performance requirement of 30dB (frequency 40GHz), the maximum size of a single window / hole cannot exceed 0.1mm. In this case, for metal structures that also need to consider heat dissipation and ventilation, normal ventilation and heat dissipation are impossible. This creates a contradictory technical problem: for ventilation, the opening must be relatively large (e.g., aperture 3mm or more), while for better electromagnetic shielding performance, the opening size must be small enough (e.g., aperture 0.1mm or less).

[0004] In such cases, it is currently difficult to solve these problems using a simple, perforated overall metal shielding structure. The commonly used approach is as follows: First, due to heat dissipation and ventilation requirements, the overall shielding structure must have relatively large openings, resulting in poor shielding performance. Second, to compensate for the insufficient electromagnetic shielding performance of the overall structure, multiple (layers) of independent shielding structures are used to reinforce key core modules / components within the equipment (different independent shielding structures are installed for the core area, the vicinity of the core, and the entire equipment) to achieve a better overall electromagnetic shielding effect (e.g., ...). Figure 2(As shown). This approach can improve the overall electromagnetic shielding effect, but it is relatively complex to implement and will occupy too much internal space, increasing the complexity and cost of the equipment. Furthermore, too many independent metal shielding structures inside can easily cause EMC problems such as internal electromagnetic resonance / coupling, thereby affecting the reliability of the equipment. Summary of the Invention

[0005] In view of the problems raised in the background art, the purpose of this invention is to provide a composite shielding wall device that takes into account both electromagnetic shielding and ventilation and heat dissipation, thus solving the problem that existing electromagnetic shielding structures cannot simultaneously achieve both electromagnetic shielding and ventilation and heat dissipation.

[0006] This invention is achieved through the following technical solution:

[0007] A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation includes...

[0008] A metal shielding wall, wherein the metal shielding wall is a hollow structure, and the metal shielding wall has multiple ventilation holes on the side wall near the shielding target and the side wall away from the shielding target respectively;

[0009] Each ventilation hole is connected to a circular waveguide. The circular waveguides close to the side wall of the shielded target form a circular waveguide array 1, and the circular waveguides away from the side wall of the shielded target form a circular waveguide array 2.

[0010] The circular waveguide array 1 and the circular waveguide array 2 are arranged in parallel and staggered in the cavity of the metal shielding wall. Both the circular waveguide array 1 and the circular waveguide array 2 have waveguide openings inside the cavity, and the waveguide opening of the circular waveguide array 1 cannot be face-to-face with the waveguide opening of the circular waveguide array 2.

[0011] The circular waveguide array 1 and the circular waveguide array 2 are connected by a plastic conduit.

[0012] In the above technical solution, the circular waveguide array 1 and circular waveguide array 2 are arranged in a parallel staggered manner, so that the openings of the array waveguides on both sides of the cavity are not face to face. The opening of one array waveguide can only appear behind the opening of the other array waveguide. That is, the waveguide opening of the circular waveguide array 1 can only appear behind the waveguide opening of the adjacent circular waveguide array 2, and the waveguide opening of the circular waveguide array 2 can only appear behind the waveguide opening of the adjacent circular waveguide array 1. This also determines that after the electromagnetic wave from either array waveguide in the cavity is transmitted from the waveguide opening, it will not immediately enter the waveguide opening of the other array waveguide. Instead, it can only reach the waveguide opening of the other array waveguide after being reflected at least twice by the inner wall of the metal shielding wall. At this time, compared with the shielding device of a single circular waveguide, the composite shielding wall of the present invention is equivalent to obtaining twice the transmission waveguide length and twice the cutoff waveguide loss of a single circular waveguide. While enhancing the attenuation of electromagnetic wave signals, it also avoids the problem of excessively thick metal shielding walls caused by two sets of circular waveguide arrays directly facing each other, thus saving space for metal shielding walls.

[0013] When the electrical equipment ventilates and dissipates heat from its interior to the exterior, the airflow enters the circular waveguide array 1 through the openings in the circular waveguide array 1. Within the cavity of the metal shielding wall, it is transmitted via plastic conduits to the corresponding circular waveguides in the circular waveguide array 2, which leads to the exterior of the electrical equipment. Finally, the airflow is conducted to the exterior of the electrical equipment through the openings in the metal shielding wall of the circular waveguide array 2, thus achieving the effect of airflow ventilation and heat dissipation. Based on the fundamental principles of electromagnetic fields / waves, the plastic conduits, lacking metallic properties, cannot confine or guide electromagnetic waves during transmission, nor can they block them. Therefore, they do not affect the electromagnetic waves transmitted through the two sets of circular waveguides. The plastic conduits achieve the effect of airflow ventilation and heat dissipation without affecting the electromagnetic wave transmission and electromagnetic shielding effect within the device.

[0014] The present invention solves the problem that existing electromagnetic shielding structures cannot simultaneously achieve electromagnetic shielding and ventilation and heat dissipation through the above technical solution.

[0015] In one possible embodiment, the diameter of the ventilation hole is equal to the inner diameter of the circular waveguide.

[0016] In one possible embodiment, the circular waveguides in the circular waveguide array 1 and the circular waveguides in the circular waveguide array 2 are both cutoff waveguides of the same specifications and dimensions.

[0017] In one possible embodiment, the total length of the cutoff waveguide is calculated using the following formula:

[0018] A = 1.823f0T * 10 9 [1-(f / f0) 2 ] 1 / 2

[0019] Where A is the attenuation; f0 is the cutoff frequency; f is the frequency of the electromagnetic wave; and T is the total length of the cutoff waveguide.

[0020] In one possible embodiment, the lengths of the circular waveguides in the circular waveguide array 1 and the circular waveguides in the circular waveguide array 2 are both half the total length of the cutoff waveguide.

[0021] In one possible embodiment, the sidewall of the inner cavity of the metal shielding wall is provided with an electromagnetic absorbing material, which is used to absorb electromagnetic wave energy entering the cavity of the metal shielding wall.

[0022] In one possible embodiment, the electromagnetic absorbing material is serrated.

[0023] In one possible embodiment, the distance between two adjacent circular waveguides in the circular waveguide array 1 is greater than half a wavelength; the distance between two adjacent circular waveguides in the circular waveguide array 2 is greater than half a wavelength.

[0024] The wavelength is calculated using the highest frequency of the electromagnetic wave required for shielding.

[0025] In one possible embodiment, the shielding target includes electrical equipment and electrical components.

[0026] In one possible embodiment, the metal shielding wall is formed by assembling and closing thin metal sheets.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] 1. The composite shielding wall device of the present invention uses two sets of circular waveguide arrays of the same specifications and sizes. It utilizes the working principle of the two sets of circular waveguide arrays to attenuate electromagnetic waves transmitted in the waveguides below the cutoff frequency to suppress the energy leakage of electromagnetic waves. Thus, it can achieve good electromagnetic shielding effect while requiring large ventilation holes. It is especially suitable for shielding equipment enclosures, shielding rooms, and modular shelters with high requirements for ventilation, heat dissipation and electromagnetic shielding.

[0029] 2. Plastic conduits are used to connect the circular waveguides of the two sets of circular waveguide arrays. Therefore, without affecting the transmission of electromagnetic waves and the electromagnetic shielding effect, the airflow channel formed by the circular waveguides and plastic conduits is used to guide the airflow, realize the smooth ventilation and heat dissipation channel, and thus enable the air to circulate effectively on both sides of the metal shielding wall, thereby achieving the effect of ventilation and heat dissipation.

[0030] 3. Because the two sets of circular waveguide arrays are arranged in a parallel staggered manner, and there is no metal tube connecting the two sets of circular waveguide arrays, electromagnetic waves entering the cavity of the metal shielding wall through one set of circular waveguide arrays cannot directly enter the circular waveguide array on the other side. Instead, they need to undergo two or more reflections in the cavity of the metal shielding wall before entering the circular waveguide array on the other side. Thus, the metal shielding wall, which is equipped with sawtooth absorbing material, consumes the energy of electromagnetic waves entering the cavity by reflecting and absorbing them, thereby reducing the signal strength of electromagnetic waves entering the circular waveguide array on the other side, reducing the overall electromagnetic wave signal leakage, and further improving the electromagnetic shielding effect of the overall shielding wall device.

[0031] 4. Because the two sets of circular waveguide arrays are of the same size, separated from each other, and arranged in a parallel staggered manner, electromagnetic waves must pass through both sets of circular waveguide arrays regardless of which side they enter from and pass through the shielding wall device. This means the effective length of the cutoff waveguides through which the electromagnetic wave passes is twice the length of a single cutoff waveguide, enhancing the attenuation of the electromagnetic wave signal. Simultaneously, this structure, with its separated and parallel staggered arrangement of the two sets of circular waveguide arrays, avoids the problem of excessively thick metal walls caused by directly facing the waveguides, saving space and making the entire composite shielding wall structure more compact and efficient. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0033] Figure 1 A schematic diagram of a traditional metal shielding opening structure;

[0034] Figure 2 This is a schematic diagram of a multi-layer shielding structure;

[0035] Figure 3 This is a schematic diagram of the structure of the circular waveguide array 1 provided in Embodiment 1 of the present invention;

[0036] Figure 4 This is a schematic diagram of the structure of the circular waveguide array 2 provided in Embodiment 1 of the present invention;

[0037] Figure 5 This is a side view of the metal shielding wall provided in Embodiment 1 of the present invention;

[0038] Figure 6 This is a schematic diagram illustrating the electromagnetic shielding working principle of the composite shielding wall device provided in Embodiment 1 of the present invention;

[0039] Figure 7 This is a schematic diagram illustrating the ventilation and heat dissipation working principle of the composite shielding wall device provided in Embodiment 1 of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0041] Example 1

[0042] Figure 1 This is a schematic diagram of a traditional metal shielding opening structure, such as... Figure 1 As shown, traditional metal shielding structures require openings to ensure ventilation and heat dissipation for electrical equipment. For shielding devices operating at frequencies of 30GHz-40GHz and above, the aperture size generally cannot exceed 0.1mm to achieve good shielding performance, while ventilation and heat dissipation typically require an aperture size of 3mm or larger. Using traditional metal shielding with openings in shielding devices operating at frequencies of 30GHz-40GHz and above will lead to a decrease in electromagnetic shielding performance, thus failing to meet the performance targets. This presents a technical difficulty and contradiction: increasing the aperture size worsens the shielding effect, while not increasing the aperture size prevents adequate ventilation and heat dissipation.

[0043] Figure 2 This is a schematic diagram of a multi-layer shielding structure, as shown below. Figure 2 As shown, the triangle represents the key core component of the electrical equipment. To enhance the electromagnetic shielding effect of this component, existing technology employs a three-layer independent shielding structure. Figure 2 (Shielding 1, Shielding 2, and Shielding 3 in the diagram). Although the three-layer independent shielding structure can improve the electromagnetic shielding effect, this structure will occupy the internal space of the electrical equipment, increase the complexity and cost of the electrical equipment, and affect the reliability of the electrical equipment.

[0044] Based on the deficiencies in the existing technology, this invention provides a composite shielding wall device that balances electromagnetic shielding and ventilation / heat dissipation for engineering applications of electrical equipment requiring electromagnetic shielding frequencies of 30GHz-40GHz and above, and shielding coefficients of 30dB-40dB and above. This device ensures both ventilation / heat dissipation requirements and electromagnetic shielding performance of the electrical equipment. Specifically, a composite shielding wall device that balances electromagnetic shielding and ventilation / heat dissipation includes:

[0045] A metal shielding wall, wherein the metal shielding wall is a hollow structure, and the metal shielding wall has multiple ventilation holes on the side wall near the shielding target and the side wall away from the shielding target respectively;

[0046] Each ventilation hole is connected to a circular waveguide. The circular waveguides close to the side wall of the shielded target form a circular waveguide array 1, and the circular waveguides away from the side wall of the shielded target form a circular waveguide array 2.

[0047] The circular waveguide array 1 and the circular waveguide array 2 are arranged in parallel and staggered within the cavity of the metal shielding wall;

[0048] The circular waveguide array 1 and the circular waveguide array 2 are connected by a plastic conduit.

[0049] The principles and functions of the metal shielding wall, circular waveguide array 1, circular waveguide array 2, and plastic conduit in this invention are explained as follows:

[0050] Circular waveguide array 1 as Figure 3 As shown, Figure 3 The circular holes in the metal shielding wall are the circular holes (i.e., ventilation holes) opened on the wall surface near electrical equipment or electrical components. The circular waveguides are connected to the circular holes to form a circular waveguide array 1. The circular waveguide array 1 is fixed in the cavity of the metal shielding wall through the circular holes.

[0051] Circular waveguide array 2 as Figure 4 As shown, Figure 4 The circular hole in the middle is a circular hole (i.e. a ventilation hole) opened on the wall surface of the metal shielding wall near electrical equipment or electrical components. The circular waveguide is connected to the circular hole 2 to form a circular waveguide array 2. The circular waveguide array 2 is fixed in the cavity of the metal shielding wall through the circular hole.

[0052] Circular waveguide array 1 and circular waveguide array 2 are respectively mounted on two opposite walls of a metal shielding wall, arranged in a parallel and staggered manner. According to the principle of waveguide transmission of electromagnetic waves, for electromagnetic waves below the waveguide cutoff frequency, the waveguide will greatly attenuate the energy of these electromagnetic waves; for electromagnetic waves above the cutoff frequency, they can be transmitted smoothly through the waveguide. In this invention, the circular waveguides corresponding to circular waveguide array 1 and circular waveguide array 2 are used as cutoff waveguides. The attenuation effect of the cutoff waveguide on electromagnetic waves below the waveguide cutoff frequency is utilized to effectively attenuate the electromagnetic wave signals.

[0053] Because circular waveguide array 1 and circular waveguide array 2 are separated and arranged in a parallel staggered configuration, electromagnetic waves must pass through both arrays regardless of which side they enter from and pass through the device. This means the total length of the cutoff waveguides traversed by the electromagnetic wave is twice the length of a single cutoff waveguide, enhancing the attenuation of the electromagnetic signal. Furthermore, the parallel staggered arrangement of the two circular waveguide arrays not only enhances signal attenuation but also avoids the problem of excessively thick metal shielding walls caused by directly facing the two arrays, thus saving space in the metal shielding wall.

[0054] It is important to emphasize that the circular waveguide arrays 1 and 2 are arranged in a parallel, staggered configuration. This means that the openings of the waveguide arrays on both sides of the cavity are not face-to-face. The opening of one waveguide array can only appear behind the opening of the other; that is, the waveguide opening of circular waveguide array 1 can only appear behind the waveguide opening of the adjacent circular waveguide array 2, and vice versa. This also means that after electromagnetic waves from either side of the waveguide array exit the cavity, they will not immediately enter the waveguide opening of the other side. Instead, they will undergo at least two reflections through the inner wall of the metal shielding wall before reaching the waveguide opening of the other side. Therefore, compared to a single circular waveguide shielding device, the composite shielding wall of this invention effectively achieves twice the transmission waveguide length and twice the cutoff waveguide loss of a single circular waveguide.

[0055] At the same time, this staggered arrangement saves more space than the method of installing two sets of waveguides facing each other in a straight line.

[0056] In one possible embodiment, the diameter of the ventilation hole is equal to the inner diameter of the circular waveguide.

[0057] In one possible embodiment, the circular waveguides in the circular waveguide array 1 and the circular waveguides in the circular waveguide array 2 are both cutoff waveguides of the same specifications and dimensions.

[0058] It should be noted that different specifications of the circular waveguide (diameter, shape, size, etc.) will affect the cutoff frequency and cutoff waveguide loss. Therefore, the present invention uses cutoff waveguides of the same specifications and size to improve working efficiency and effect.

[0059] In one possible embodiment, the total length of the cutoff waveguide is calculated using the following formula:

[0060] A = 1.823f0T * 10 9 [1-(f / f0) 2 ] 1 / 2

[0061] Where A is the attenuation; f0 is the cutoff frequency; f is the frequency of the electromagnetic wave; and T is the total length of the cutoff waveguide.

[0062] According to relevant theories of electromagnetic field microwave technology, electromagnetic waves below the cutoff frequency that fall within the cutoff region of a waveguide will experience attenuation when passing through the waveguide. This attenuation is called the absorption loss of the cutoff waveguide. The engineering estimation formula for the absorption loss of the cutoff waveguide is shown in the above formula. Where A is the attenuation (unit: dB); f0 is the cutoff frequency (unit: Hz); f is the frequency of the electromagnetic wave; and T is the total length of the cutoff waveguide (unit: cm).

[0063] It should be noted that, in specific applications, those skilled in the art can determine the cutoff frequency value (not lower than the upper limit value) based on the upper limit value of the actual electromagnetic shielding frequency, and thereby determine the size of the circular waveguide opening. Furthermore, the length of the cutoff waveguide can be determined according to the requirements of the shielding specifications.

[0064] In one possible embodiment, the lengths of the circular waveguides in the circular waveguide array 1 and the circular waveguides in the circular waveguide array 2 are both half the total length of the cutoff waveguide.

[0065] It should be noted that, since the circular waveguide array 1 and circular waveguide array 2 in this invention are arranged in a parallel staggered manner, the length of a single circular waveguide in each group of circular waveguide arrays is half the total length T of the cutoff waveguide, thereby saving space in the metal shielding wall.

[0066] In one possible embodiment, the distance between two adjacent circular waveguides in the circular waveguide array 1 is greater than half a wavelength; the distance between two adjacent circular waveguides in the circular waveguide array 2 is greater than half a wavelength.

[0067] It should be noted that, based on the electromagnetic wave aperture coupling theory and the basic principle of cutoff waveguides, since the distance between adjacent apertures in a circular waveguide array is greater than half a wavelength, the multiple apertures in the circular waveguide array in this invention will not reduce the shielding effectiveness.

[0068] Metal shielding wall, such as Figure 5 As shown, the metal shielding wall has a hollow structure, with a metal plate surface and a metal cavity. A circular hole 1 is provided on the side of the metal shielding wall closest to the electrical equipment, and a circular hole 2 is provided on the side furthest from the electrical equipment. Circular hole 1 is used to assemble circular waveguide array 1, and circular hole 2 is used to assemble circular waveguide array 2. Circular waveguide array 1 and circular waveguide array 2 are arranged in parallel, staggered arrangement within the cavity of the metal shielding wall.

[0069] The electromagnetic shielding working principle of the composite shielding wall device is as follows: Figure 6 As shown (it should be noted that this is for illustrative purposes only), Figure 6The diagram only shows the transmission of electromagnetic waves from the left to the right circular waveguide array (in reality, electromagnetic waves can also transmit from the right to the left). When an electromagnetic wave enters a circular waveguide through an opening in either array, it is attenuated and reaches the end of the waveguide. There, it enters the cavity of the metal shielding wall and is reflected by the metal inner wall opposite the waveguide. Part of the reflected wave is reflected again by the metal inner wall on the other side. After two reflections, a portion of the wave enters another circular waveguide array, where it continues to attenuate during further transmission. The portion that fails to enter the other array is reflected multiple times within the cavity of the metal shielding wall. With the metal shielding wall and the parallel staggered circular waveguide arrays 1 and 2 of the present invention, electromagnetic wave signals, regardless of which set of circular waveguide arrays they enter from, will undergo at least two reflections in the cavity of the metal shielding wall before reaching the other set of circular waveguide arrays. This structure helps to achieve a better overall electromagnetic shielding effect.

[0070] In one possible embodiment, the sidewall of the inner cavity of the metal shielding wall is provided with an electromagnetic absorbing material, which is used to absorb electromagnetic wave energy entering the cavity of the metal shielding wall.

[0071] In one possible embodiment, the electromagnetic absorbing material is serrated.

[0072] It should be noted that, as can be seen from the working principle of the cutoff waveguide above, the cutoff waveguide can be used to attenuate electromagnetic waves below the waveguide cutoff frequency, thereby effectively attenuating the electromagnetic wave signal. However, for electromagnetic wave signals with relatively high frequencies that are closer to the cutoff frequency, the attenuation effect of the cutoff waveguide is less effective.

[0073] Therefore, to enhance the absorption of electromagnetic wave energy, this invention incorporates electromagnetic absorbing material on the sidewalls of the inner cavity of the metal shielding wall. In this case, the electromagnetic wave signal is reflected and absorbed by the absorbing material within the metal wall cavity. This not only mitigates reflection loss but also absorbs electromagnetic wave energy, further attenuating the electromagnetic wave signal and contributing to a better overall electromagnetic shielding effect. Furthermore, serrated edges on the electromagnetic absorbing material further enhance the absorption effect.

[0074] like Figure 7 As shown, a plastic conduit is located inside the cavity of the metal wall, connecting parallel, staggered circular waveguide arrays 1 and 2. The function of this plastic conduit in this invention is to guide ventilation airflow, forming a complete and unobstructed airflow channel. The ventilation and heat dissipation working principle of the composite shielding wall device is as follows: Figure 7As shown, when the electrical equipment is ventilated and cooled from the inside to the outside, the airflow enters the circular waveguide array 1 through the opening of the circular waveguide array 1. In the cavity of the metal shielding wall, it is transmitted through the plastic conduit into the relevant circular waveguide of the circular waveguide array 2 leading to the outside of the electrical equipment. Finally, it is conducted to the outside of the electrical equipment through the opening of the circular waveguide array 2 in the metal shielding wall, thus achieving the effect of airflow ventilation and cooling of the electrical equipment.

[0075] Based on the fundamental principles of electromagnetic fields / waves, plastic conduits, lacking metallic properties, cannot confine or guide electromagnetic waves during transmission, nor can they block them. Therefore, they will not affect the electromagnetic waves transmitted through the two sets of circular waveguides. Figure 6 As shown, when an electromagnetic wave entering a certain set of circular waveguide arrays reaches the end of the circular waveguide, it is not affected by the plastic conduit and can directly enter the cavity inside the metal wall. After two or more electromagnetic wave reflections / absorptions, it may enter another set of circular waveguide arrays.

[0076] The plastic duct achieves the effect of airflow ventilation and heat dissipation, without affecting the electromagnetic wave transmission and electromagnetic shielding effect within the device.

[0077] In one possible embodiment, the shielding target includes electrical equipment and electrical components.

[0078] It should be noted that the composite shielding wall device provided by the present invention can be used as a shielding wall in an electrical equipment room, or as a chassis shell of electrical equipment (i.e., part of the electrical equipment).

[0079] In one possible embodiment, the metal shielding wall is formed by assembling and closing thin metal sheets.

[0080] The working principle of this invention is as follows:

[0081] When electromagnetic waves leak from inside electrical equipment to the outside, they enter circular waveguide array 1. After being attenuated by the cutoff waveguide of the circular waveguide array, they enter the cavity of the metal shielding wall. After being reflected at least twice by the metal shielding wall and absorbed by the sawtooth absorbing material on the inner wall of the metal shielding wall cavity, they enter circular waveguide array 2 and are attenuated again by the cutoff waveguide. The signal energy of the electromagnetic waves leaking from inside the electrical equipment to the outside is greatly consumed by the electromagnetic wave transmission attenuation effect of the two sets of circular waveguide arrays and the electromagnetic wave reflection and absorption effect of the cavity inside the metal wall, thus achieving an overall electromagnetic shielding effect.

[0082] When electromagnetic waves enter the electrical equipment from the outside, they enter the circular waveguide array 2. After being attenuated by the cutoff waveguide of the circular waveguide array, they enter the cavity of the metal shielding wall. After being reflected at least twice by the metal shielding wall and absorbed by the sawtooth absorbing material on the inner wall of the metal shielding wall cavity, they enter the circular waveguide array 1 and are attenuated again by the cutoff waveguide. The signal energy of the electromagnetic waves entering the electrical equipment from the outside is greatly consumed by the electromagnetic wave transmission attenuation effect of the two sets of circular waveguide arrays and the electromagnetic wave reflection and absorption effect of the cavity inside the metal wall, thus achieving a better overall electromagnetic shielding effect.

[0083] At the same time, the airflow passes through a complete straight airflow channel formed by two sets of circular waveguide arrays and a plastic duct connecting the two sets of circular waveguide arrays, realizing the exchange of airflow between the inside and outside of the electrical equipment, thereby achieving the effect of ventilation and heat dissipation.

[0084] Example 2

[0085] Based on Example 1, Example 2 provides an embodiment of a composite shielding wall device that combines electromagnetic shielding and ventilation and heat dissipation, applied to a certain electrical equipment or electrical component.

[0086] A certain electrical equipment or component requires that the diameter of the ventilation hole be no less than 3mm, the center distance between adjacent holes in the circular waveguide array be no less than 2.5 times the diameter, and the electromagnetic shielding coefficient be no less than 60dB (frequency 0.1GHz-40 GHz).

[0087] For the technical requirement of an electromagnetic shielding coefficient of not less than 60dB (frequency 0.1GHz-40 GHz), if conventional electromagnetic shielding / metal structure opening technology is used, the maximum opening diameter cannot exceed 0.065mm. Obviously, the opening diameter data cannot meet the opening requirements for ventilation and heat dissipation.

[0088] The composite shielding wall device provided in Example 1, which combines electromagnetic shielding and ventilation / heat dissipation, can ensure the achievement of electromagnetic shielding targets and shielding effects while satisfying airflow ventilation and heat dissipation requirements. Specific applications are as follows:

[0089] First, based on the requirements of electromagnetic shielding technology and using the relevant theory of cutoff waveguides, it is determined that the cutoff frequency must be higher than 40GHz. In order to obtain a better attenuation effect, this embodiment considers using a cutoff frequency of 50GHz to design the cutoff waveguide. At this time, the corresponding aperture is 3.5mm, which meets the requirement that the aperture of the ventilation hole of electrical equipment or electrical components should not be less than 3mm.

[0090] According to the cutoff waveguide attenuation theory, the attenuation calculation formula of the cutoff waveguide can be used to estimate that when the total length T of the cutoff waveguide is 12mm, the waveguide attenuates the electromagnetic wave signal by 64dB, which meets the electromagnetic shielding requirements.

[0091] Since this invention employs two sets of circular waveguide arrays of the same size arranged in parallel and staggered configurations, the length of a single circular waveguide in each set is half the total length T, i.e., 6 mm. Considering the parallel and staggered arrangement of the two sets of circular waveguide arrays, the thickness of the metal shielding wall can be set to 10 mm.

[0092] The metal shielding wall is formed by assembling and closing thin metal plates. Holes are opened on the thin metal plates to assemble and weld circular waveguide arrays. At the same time, absorbing material is placed on the inner cavity sidewall of the metal shielding wall, and two sets of circular waveguide arrays are connected by plastic conduits.

[0093] Previously, we designed and evaluated the electromagnetic wave attenuation effect of the cutoff waveguide. Because the spacing between adjacent apertures in the circular waveguide array is relatively large (greater than half the wavelength), the multiple apertures in the waveguide array do not reduce the shielding effectiveness in this application. Furthermore, the metal shielding wall cavity, equipped with electromagnetic absorbing material, reflects and absorbs the electromagnetic waves entering the cavity. Therefore, the overall structure of the composite shielding wall device will attenuate electromagnetic waves entering the device by more than 64 dB, and the actual electromagnetic shielding coefficient can generally reach 70 dB.

[0094] Therefore, the composite shielding wall device provided by this invention solves the need for ventilation and heat dissipation through openings while avoiding the electromagnetic leakage problem caused by large opening diameters. Compared with traditional metal opening shielding technology, the aperture (3.5mm) is more than 50 times larger than that of conventional technology (<0.065mm), yet the electromagnetic shielding performance not only does not decrease but also has a margin compared to the performance requirements.

[0095] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation, characterized in that, include: A metal shielding wall, wherein the metal shielding wall is a hollow structure, and the metal shielding wall has multiple ventilation holes on the side wall near the shielding target and the side wall away from the shielding target respectively; Each ventilation hole is connected to a circular waveguide. The circular waveguides close to the side wall of the shielded target form a circular waveguide array 1, and the circular waveguides away from the side wall of the shielded target form a circular waveguide array 2. The circular waveguide array 1 and the circular waveguide array 2 are arranged in parallel and staggered in the cavity of the metal shielding wall. Both the circular waveguide array 1 and the circular waveguide array 2 have waveguide openings inside the cavity, and the waveguide opening of the circular waveguide array 1 cannot be face-to-face with the waveguide opening of the circular waveguide array 2. The circular waveguide array 1 and the circular waveguide array 2 are connected by a plastic conduit; Both the circular waveguides in the circular waveguide array 1 and the circular waveguides in the circular waveguide array 2 are cutoff waveguides of the same specifications and dimensions. The lengths of the circular waveguides in the circular waveguide array 1 and the circular waveguides in the circular waveguide array 2 are both half the total length of the cutoff waveguide.

2. The composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 1, characterized in that, The diameter of the ventilation hole is equal to the inner diameter of the circular waveguide.

3. The composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 1, characterized in that, The total length of the cutoff waveguide is calculated using the following formula: Where A represents attenuation; The cutoff frequency; denoted as , where is the frequency of the electromagnetic wave; and T is the total length of the cutoff waveguide.

4. A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 1, characterized in that, The inner cavity of the metal shielding wall is provided with an electromagnetic absorbing material, which is used to absorb electromagnetic wave energy entering the cavity of the metal shielding wall.

5. A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 4, characterized in that, The electromagnetic absorbing material is serrated.

6. A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 1, characterized in that, In the circular waveguide array 1, the distance between two adjacent circular waveguides is greater than half a wavelength; in the circular waveguide array 2, the distance between two adjacent circular waveguides is greater than half a wavelength. The wavelength is calculated using the highest frequency of the electromagnetic wave required for shielding.

7. A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 1, characterized in that, The shielding targets include electrical equipment and electrical components.

8. A composite shielding wall device that combines electromagnetic shielding and ventilation / heat dissipation according to claim 1, characterized in that, The metal shielding wall is formed by assembling and closing thin metal plates.

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