Self-adaptive electromagnetic radiation suppression method for equipment in high-intensity radiation field

Abstract

The invention discloses a self-adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field. The method comprises the following specific steps: establishing an electronic equipment model under external plane wave irradiation; plane wave intensity is set, and field intensity distribution of an inner cavity of the electronic equipment model is obtained; determining shielding electromagnetic effect weak points according to the field intensity distribution of the inner cavity of the electronic equipment model; establishing an energy selection surface structure comprising a plurality of slot resonance patches arranged in an array; the energy selective surface structure is arranged on the surface where the shielding electromagnetic effect weak point is located, and an energy selective surface protection structure model is established; and comparing the field intensity at the shielding electromagnetic effect weak point in the energy selective surface protection structure model with a protection requirement, and judging whether the energy selective surface structure meets the protection requirement or not.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic environmental effects, and in particular to a method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field. Background Art

[0002] High-intensity radiation field (HIRF) refers to the electromagnetic environment formed by the electromagnetic waves radiated by radar, radio, navigation, broadcasting stations and other high-power transmitters from the ground, water and air. HIRF has the characteristics of wide frequency coverage, high electric field strength and long action time. It will cause harm to the normal operation of the electrical and electronic systems of the aircraft through the coupling of external strong electromagnetic fields and electronic systems, affecting the flight safety of the aircraft.

[0003] In terms of high-intensity radiation field protection, there is a patent available for reference: "A high-intensity radiation field protection structure for aviation airborne equipment", which mainly protects against HIRF through metal shielding and filtering.

[0004] According to the analysis of foreign authoritative organizations such as FAA in the aircraft development process in recent decades, the way high-intensity radiation fields are coupled to aircraft electronic systems can be summarized as follows: 1) In the 400MHz to 18GHz frequency band, high-intensity radiation field energy is mainly coupled through cabin openings, gaps and other channels; 2) In the 1MHz to 400MHz frequency band, the interconnection harness of the aircraft electronic system acts as an antenna, and the high-intensity radiation field energy is mainly coupled through the inductive coupling of the interconnection harness inside the aircraft; 3) HIRF energy below 1MHz is generally mainly coupled from the current on the aircraft surface to the inductive current of the cable harness. At present, the high-intensity radiation field protection of electronic equipment in aircraft is mainly achieved through metal shell shielding, but electromagnetic waves will couple into the inside of the equipment shell through holes and gaps, and then due to the resonance effect caused by metal reflection, standing waves will be formed at certain frequencies, thereby causing electromagnetic resonance. The field strength at the resonant frequency increases significantly, reducing the electromagnetic protection efficiency. Therefore, in order to improve the protection capability of aircraft equipment against high-intensity radiation field effects, a method for adaptive electromagnetic radiation suppression of equipment in high-intensity radiation fields is needed to achieve the function of targeted and efficient protection of equipment against high-intensity radiation field environments. Summary of the invention

[0005] The purpose of the present invention is to provide a method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field. The method adopts an energy selective surface structure, utilizes the electromagnetic wave aperture coupling mechanism, obtains the weak points of the equipment shielding effectiveness by calculating the resonant frequency of the electronic device's inner cavity, and designs the corresponding energy selective surface structure for protection according to the resonant frequency at the weak points of the shielding effectiveness.

[0006] In order to achieve the above object, the present invention provides a method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field, and the specific steps include:

[0007] Step 1, establishing an electronic device model under external plane wave irradiation;

[0008] Step 2, setting the plane wave intensity to obtain the field intensity distribution in the inner cavity of the electronic device model;

[0009] Step 3, determining the weak points of electromagnetic shielding effect according to the field strength distribution in the inner cavity of the electronic equipment model;

[0010] Step 4, establishing an energy selective surface structure including a plurality of slot resonant patches arranged in an array;

[0011] Step 5, setting the energy selective surface structure on the surface where the weak point of shielding electromagnetic effect is located, and establishing an energy selective surface protection structure model; comparing the field strength at the weak point of shielding electromagnetic effect in the energy selective surface protection structure model with the protection requirement, and judging whether the energy selective surface structure meets the protection requirement.

[0012] Optionally, in step 4, each of the slot resonant patches is a square metal sheet, including one or more slots and diodes with the same number of slots; each of the slots is parallel to the edge of the slot resonant patch, and a diode is provided at the center of each slot; the conductive direction of the diode is perpendicular to the length direction of the slot.

[0013] Optionally, when there are a plurality of slots on the slot resonant patch, the plurality of slots are symmetrically arranged about the center point of the slot resonant patch, the sizes of two symmetrical slots are the same, and the diodes on the slots are also arranged in the same direction.

[0014] Optionally, when there are multiple resonant frequency points in the electronic device model, each slot resonant patch in the energy selective surface structure includes two coaxially arranged square ring slots, namely a first square ring slot and a second square ring slot, the size of the first square ring slot is larger than the size of the second square ring slot, and the first square ring slot is sleeved on the outside of the second square ring slot; each square ring slot is composed of four slots of the same size and four diodes, and the diodes arranged in the middle position of two parallel slots in each square ring slot are in the same direction.

[0015] Optionally, the ratio of the length L to the width w of the slot is greater than 1, and the length L of the slot is 1 / 2 of the wavelength corresponding to the resonant frequency, which can be expressed as:

[0016]

[0017] Where f is the resonant frequency at the weak point of shielding electromagnetic effect, and v is the wave velocity of the plane wave.

[0018] Optionally, step 5 further includes: setting a field intensity threshold in the inner cavity of the electronic device model;

[0019] When the field strength at the weak point of the shielding electromagnetic effect is greater than or equal to the field strength threshold, it is necessary to return to step S4 to adjust the energy selective surface structure, change the gap length on the gap resonance patch and the operating frequency of the diode, and recalculate the field strength at this point; when the field strength at this point is less than the field strength threshold, it means that the energy selective surface structure meets the protection requirements.

[0020] Optionally, in step 1, the electronic device model includes: a metal shell of the electronic device, pores on the surface of the electronic device; there is a cavity inside the electronic device model, and when the electronic device model is in a plane wave, the plane wave can irradiate the pores on the electronic device model and irradiate into the cavity of the electronic device model through the pores.

[0021] Optionally, step 3 further includes: the weak point of shielding electromagnetic effect is the inner cavity at the pore of the electronic device model, and the field strength E" of the inner cavity at the pore of the electronic device model can be expressed as:

[0022]

[0023] Where a is the radius of the pore, S is the area of ​​the pore, R is the distance from the test point in the inner cavity of the electronic device model to the pore, E is the field intensity of the plane wave, θ is the angle between the incident direction of the plane wave and the height direction of the electronic device model, k is the transmission constant, J1 is the first-order Bessel function, and i and j are imaginary units.

[0024] Optionally, in step 2, the electronic device model is simulated by changing the irradiation angle of the plane wave and the frequency of the plane wave to obtain the field intensity distribution in the inner cavity of the electronic device model under different irradiation angles and polarization conditions; wherein the frequency of the plane wave does not exceed 18 GHz.

[0025] Optionally, the frequency range of the plane wave is 100 MHz to 6 GHz.

[0026] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0027] The present invention simplifies the modeling of the electronic device, calculates the shielding effectiveness weak points of the electronic device, and establishes the energy selective surface protection structure model by constructing the energy selective surface structure, and compares the field strength at the shielding effectiveness weak points to determine whether the energy selective surface structure can meet the protection requirements of the electronic device; and by changing the gap length and the operating frequency of the diode in the energy selective surface structure, the energy selective surface structure is automatically adjusted, so that the energy selective surface structure finally obtained in the method of the present invention meets the protection requirements of the electronic device. The method of the present invention can adjust the required energy selective surface structure according to the protection requirements of the electronic device, and can be designed according to different protection requirements to achieve better protection effects, and the process of designing the energy selective surface structure is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of the method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field.

[0029] Figure 2 It is a schematic diagram of an electronic device model of the method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field of the present invention.

[0030] Figure 3 This is a diagram of the slot structure of the slot resonant patch of the method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field of the present invention.

[0031] Figure 4 It is a structural diagram of the slot resonant patch of the method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field of the present invention.

[0032] Figure 5 This is a structural diagram of the energy-selective surface protection structure model of the method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field of the present invention.

[0033] In the figure, 1-electronic device model, 11-pore, 2-slot resonant patch, 21-slot, 22-diode, 3-energy selective surface structure. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] like Figure 1 As shown, the present invention provides a method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field, and the specific steps include:

[0038] Step 1: Establish a model of an electronic device under external plane wave irradiation.

[0039] In the process of modeling the electronic equipment in the aircraft, the wave-transmitting materials, the internal fine structures, the internal structures in the closed metal parts and the non-metallic patches in the layered structures in the electronic equipment are ignored to obtain a simplified electronic equipment model 1 of the electronic equipment, such as Figure 2 As shown. The electronic device model includes: a metal shell of the electronic device, and pores 11 on the surface of the electronic device, so that there is a cavity inside the electronic device model 1, and the surface of the electronic device model 1 is provided with pores 11, ensuring that when the electronic device model 1 is in a high-intensity radiation field (HIRF), the plane waves in the high-intensity radiation field can irradiate the pores 11 on the electronic device model 1, and irradiate into the cavity of the electronic device model 1 through the pores 11. Wherein, the wave-transmitting material includes: plastic, glass.

[0040] Step 2: Set the plane wave intensity to obtain the field intensity distribution in the cavity of the electronic device model.

[0041] According to the time when the electronic device is exposed to radiation, the intensity E and frequency of the plane wave in the high-intensity radiation field are set. The electronic device model 1 is simulated by changing the irradiation angle of the plane wave and the frequency of the plane wave to obtain the field intensity distribution of the inner cavity of the electronic device model 1 under different irradiation angles and polarization conditions. Among them, the frequency range of the plane wave is selected according to the type of electronic device, and the maximum frequency does not exceed 18GHz. Usually, the frequency range of the plane wave is 100MHz to 6GHz.

[0042] Step 3, determining the resonant frequency of the inner cavity of the electronic device model.

[0043] According to the field strength distribution of the inner cavity of the electronic device model 1 obtained in step 2, the inner cavity of the electronic device model 1 is simulated and calculated to determine the weak point of the shielding electromagnetic effect, and then the resonant frequency of the point is obtained through simulation calculation.

[0044] The electromagnetic shielding effect is related to the field strength obtained by the inner cavity test of the electronic device model 1, as shown in Formula 1. When the electromagnetic shielding effect is weak, the inner cavity field strength of the electronic device model 1 is closer to the external field strength, so the inner cavity at the aperture 11 of the electronic device model 1 is a weak point of the electromagnetic shielding effect.

[0045]

[0046] Where, E is the field strength at any test point in the inner cavity of the electronic equipment model when no shielding is added, that is, the field strength environment in which the electronic equipment model is located; E'' is the field strength at any test point in the inner cavity of the electronic equipment model when shielding is added, that is, the field strength in the inner cavity of the electronic equipment model; SSE is the shielding effectiveness.

[0047] Under the influence of the plane wave, due to the charge layer phenomenon on the metal surface, charge deposition occurs at the edge of the pore 11 of the electronic device model 1. At this time, the pore 11 can be equivalent to a dipole antenna emitting electromagnetic energy to the inner cavity of the electronic device model 1, forming a complex electromagnetic environment. Therefore, the field strength E" of the inner cavity at the pore 11 of the electronic device model 1 can be expressed as:

[0048]

[0049] Wherein, a is the radius of the pore 11, S is the area of ​​the pore 11, R is the distance from the test point in the inner cavity of the electronic device model to the pore, E is the field intensity of the plane wave, θ is the angle between the incident direction of the plane wave and the height direction of the electronic device model, k is the transmission constant, J1 is the first-order Bessel function, and i and j are imaginary units.

[0050] Step 4: Establish energy selective surface structure.

[0051] Aiming at the resonant frequency protection requirement at the pore 11 of the electronic device model 1, an energy selective surface structure 3 with single-frequency working characteristics is designed. Figure 5 As shown, the energy selective surface structure 3 includes a plurality of slot resonant patches 2 arranged in an array.

[0052] Each of the slot resonant patches 2 is a square metal sheet. According to the protection requirements, the slot resonant patch 2 includes one or more slots 21 and the same number of diodes 22 as the slots 21. Figure 3 As shown, each of the slots 21 is parallel to the edge of the slot resonant patch 2 , and a diode 22 is provided at the center of the slot 21 , so that the slot resonant patch 2 forms a passive structure; the conductive direction of the diode 22 is perpendicular to the length direction of the slot 21 .

[0053] Specifically, Figure 3 As shown, when there is one slot 21 on the slot resonant patch 2, the slot 21 is parallel to the edge of the slot resonant patch 2 and is arranged at the center of the slot resonant patch 2. At this time, the energy selective surface structure 3 composed of a plurality of slot resonant patches 2 is suitable for single frequency point shielding.

[0054] Specifically, Figure 4 As shown, when there are a plurality of slots 21 on the slot resonant patch 2, the plurality of slots 21 are parallel to the edge of the slot resonant patch 2 and are symmetrically arranged with respect to the center point of the slot resonant patch 2. At this time, the two symmetrical slots 21 (i.e., the length directions of the slots 21 are the same and the distances between the slots 21 and the center points of the slot resonant patch 2 are the same) have the same size, and the diodes 22 on the slots 21 are also arranged in the same direction, ensuring that the diodes 22 can form a passage through the slots 21 on the slot resonant patch 2.

[0055] In a preferred embodiment, when the electronic device model 1 has multiple resonant frequency points, an energy selective surface structure 3 with dual-frequency or even multi-frequency working characteristics needs to be designed, and the plurality of slots 21 on each slot resonant patch 2 in the energy selective surface structure 3 are arranged in a “U” shape, such as Figure 4 As shown, the slot resonant patch 2 includes two coaxially arranged square ring slots, namely the first square ring slot and the second square ring slot. The size of the first square ring slot is larger than the size of the second square ring slot, and the first square ring slot is sleeved on the outside of the second square ring slot. Each square ring slot is composed of four slots 21 of the same size and four diodes 22; the diodes 22 arranged in the middle position of two parallel slots 21 in each square ring slot are in the same direction. Among them, the length of the slot 21 of the first square ring slot, the length of the slot 21 of the second square ring slot, and the selected working frequency of the diode 22 determine the working frequency of the energy selective surface structure 3.

[0056] Specifically, the ratio of the length L to the width w of the slot 21 is greater than 1, that is, L / w>1, wherein the length L of the slot 21 is 1 / 2 of the wavelength corresponding to the resonant frequency, which can be expressed as:

[0057]

[0058] Where f is the resonant frequency at the weak point of shielding electromagnetic effect, and v is the wave velocity of the plane wave.

[0059] Circuit simulation is performed on the slot 21 and the diode 22 on the slot resonant patch 2 in the energy selective surface structure 3 to obtain an equivalent circuit model. The slot resonant patch 2 when the diode 22 is turned on is regarded as a resistor connected in series with the lead inductance, and the slot resonant patch 2 when the diode 22 is turned off is regarded as a capacitor connected in series with the lead inductance. Therefore, the equivalent circuit model can be expressed as:

[0060]

[0061] Where f0 is the resonant frequency of the equivalent circuit model, l is the lead inductance, and C is the capacitance.

[0062] When the diode 22 in the energy selective surface structure 3 is turned on, the energy selective surface can reflect electromagnetic waves, thereby achieving the protective effect of the energy selective surface structure 3 in a high-intensity radiation field.

[0063] The equivalent circuit model is jointly simulated with the energy selective surface energy structure to obtain the electromagnetic protection characteristics of the energy selective surface.

[0064] Step 5: Establish an energy selective surface protection structure model to determine whether the energy selective surface structure meets the protection requirements.

[0065] According to the protection requirements, the field strength threshold in the inner cavity of the electronic device model 1 is set.

[0066] The energy selective surface structure 3 in step 4 is set on the surface where the pores 11 are located in the electronic device model 1, and an energy selective surface protection structure model is established. The energy selective surface protection structure model is in a plane wave, and a full-wave simulation of the loading circuit is performed, and the shielding effectiveness of the weak point of the shielding electromagnetic effect of the original electronic device model 1 in the energy selective surface protection structure model is evaluated, and the field strength at the point is obtained through simulation.

[0067] When the field strength at this point is greater than or equal to the field strength threshold, it is necessary to return to step S4 to adjust the energy selective surface structure 3, change the length of the slot 21 on the slot resonant patch 2 and the operating frequency of the diode 22, and recalculate the field strength at this point; when the field strength at this point is less than the field strength threshold, it means that the energy selective surface structure 3 in step 4 can play a role in protecting electronic equipment in high-intensity radiation fields.

[0068] In summary, the present invention establishes an energy selective surface protection structure model by constructing an energy selective surface structure, and compares the field strength at the weak points of shielding effectiveness to determine whether the energy selective surface structure can meet the protection requirements of electronic equipment; at the same time, the present invention can automatically design an energy selective surface structure according to different protection requirements to achieve better protection effects, and the process of designing the energy selective surface structure is more convenient.

[0069] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field, characterized in that: The specific steps include: Step 1, establishing an electronic device model under external plane wave irradiation; Step 2, setting the plane wave intensity to obtain the field intensity distribution in the inner cavity of the electronic device model; Step 3, determining the weak points of electromagnetic shielding effect according to the field strength distribution in the inner cavity of the electronic equipment model; Step 4, establishing an energy selective surface structure including a plurality of slot resonant patches arranged in an array; Step 5, setting the energy selective surface structure on the surface where the weak point of shielding electromagnetic effect is located, and establishing an energy selective surface protection structure model; comparing the field strength at the weak point of shielding electromagnetic effect in the energy selective surface protection structure model with the protection requirement, and judging whether the energy selective surface structure meets the protection requirement.

2. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 1 is characterized in that: In step 4, each of the slot resonant patches is a square metal sheet, including one or more slots and diodes with the same number of slots; each of the slots is parallel to the edge of the slot resonant patch, and a diode is provided at the center of each slot; the conductive direction of the diode is perpendicular to the length direction of the slot.

3. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 2, characterized in that: When there are a plurality of slots on the slot resonant patch, the slots are symmetrically arranged about the center point of the slot resonant patch, the sizes of two symmetrical slots are the same, and the diodes on the slots are also arranged in the same direction.

4. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 2, characterized in that: When there are multiple resonant frequency points in the electronic device model, each slot resonant patch in the energy selective surface structure includes two coaxially arranged square ring slots, namely a first square ring slot and a second square ring slot. The size of the first square ring slot is larger than that of the second square ring slot, and the first square ring slot is sleeved on the outside of the second square ring slot. Each square ring slot is composed of four slots of the same size and four diodes, and the diodes arranged in the middle position of two parallel slots in each square ring slot have the same direction.

5. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 4, characterized in that: The ratio of the length L to the width w of the slot is greater than 1. The length L of the slot is 1 / 2 of the wavelength corresponding to the resonant frequency, which can be expressed as: Where f is the resonant frequency at the weak point of shielding electromagnetic effect, and v is the wave velocity of the plane wave.

6. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 5, characterized in that: Step 5 also includes: setting a field intensity threshold in the inner cavity of the electronic device model; When the field strength at the weak point of the shielding electromagnetic effect is greater than or equal to the field strength threshold, it is necessary to return to step S4 to adjust the energy selective surface structure, change the gap length on the gap resonance patch and the operating frequency of the diode, and recalculate the field strength at this point; when the field strength at this point is less than the field strength threshold, it means that the energy selective surface structure meets the protection requirements.

7. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 1, characterized in that: In step 1, the electronic device model includes: a metal shell of the electronic device and pores on the surface of the electronic device; there is a cavity inside the electronic device model. When the electronic device model is in a plane wave, the plane wave can irradiate the pores on the electronic device model and irradiate into the cavity of the electronic device model through the pores.

8. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 7, characterized in that: Step 3 also includes: the weak point of the shielding electromagnetic effect is the inner cavity at the pore of the electronic device model, and the field strength E" of the inner cavity at the pore of the electronic device model can be expressed as: Where a is the radius of the pore, S is the area of ​​the pore, R is the distance from the test point in the inner cavity of the electronic device model to the pore, E is the field intensity of the plane wave, θ is the angle between the incident direction of the plane wave and the height direction of the electronic device model, k is the transmission constant, J1 is the first-order Bessel function, and i and j are imaginary units.

9. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 1, characterized in that: The step 2 is to simulate the electronic device model by changing the irradiation angle of the plane wave and the frequency of the plane wave to obtain the field intensity distribution of the inner cavity of the electronic device model under different irradiation angles and polarization conditions; wherein the frequency of the plane wave does not exceed 18 GHz.

10. The method for adaptively suppressing electromagnetic radiation of equipment in a high-intensity radiation field according to claim 9, characterized in that: The frequency range of the plane wave is 100 MHz to 6 GHz.

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