A method for adaptive electromagnetic radiation suppression of equipment in a high intensity radiation field

Abstract

The application discloses a kind of high-strength radiation field equipment adaptive electromagnetic radiation suppression methods, specific steps include: establishing the electronic equipment model under the irradiation of external plane wave;Set the plane wave intensity, obtain the field intensity distribution of the electronic equipment model inner cavity;According to the field intensity distribution of the electronic equipment model inner cavity, determine the shielding electromagnetic effect weak point;Establish energy selection surface structure including several array arrangement gap resonant patch;The energy selection surface structure is set on the surface where shielding electromagnetic effect weak point is located, and an energy selection surface protection structure model is established;The field intensity at shielding electromagnetic effect weak point in energy selection surface protection structure model is compared with protection demand, to judge whether energy selection surface structure satisfies protection demand.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic environment effects technology, specifically to an adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field. Background Technology

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

[0003] The patent available for high-intensity radiation field protection is "A high-intensity radiation field protection structure for airborne equipment", which mainly protects against HIRF through metal shielding and filtering.

[0004] According to analyses conducted by authoritative international organizations such as the FAA during aircraft development over the past few decades, the ways in which high-intensity radiated fields couple into aircraft electronic systems can be summarized as follows: 1) In the 400MHz–18GHz frequency band, high-intensity radiated field energy is mainly coupled through cabin openings and gaps; 2) In the 1MHz–400MHz frequency band, the interconnecting wiring harnesses of the aircraft electronic systems act as antennas, and high-intensity radiated field energy is mainly coupled through inductive coupling via the internal interconnecting wiring harnesses; 3) HIRF energy below 1MHz is generally coupled primarily through the induced current from the aircraft surface current to the wiring harnesses. Currently, protection against high-intensity radiated fields in aircraft electronic equipment mainly relies on metal casing shielding. However, electromagnetic waves can couple into the equipment casing through openings and gaps, leading to resonance effects due to metal reflection. This can create standing waves at certain frequencies, resulting in electromagnetic resonance. At the resonance frequency, the field strength increases significantly, reducing the effectiveness of electromagnetic protection. Therefore, to improve the protection capability of aircraft equipment against high-intensity radiated field effects, an adaptive electromagnetic radiation suppression method for equipment in high-intensity radiated fields is needed to achieve targeted and efficient protection against high-intensity radiated field environments. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive electromagnetic radiation suppression method for equipment in high-intensity radiation fields. It adopts an energy-selective surface structure and utilizes the electromagnetic wave aperture coupling mechanism. By calculating the resonant frequency of the internal cavity of the electronic device, the weak point of the equipment's shielding effectiveness is obtained, and a corresponding energy-selective surface structure is designed to protect the weak point of the shielding effectiveness based on the resonant frequency of the weak point.

[0006] To achieve the above objectives, the present invention provides an adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field, the specific steps of which include:

[0007] Step 1: Establish an electronic device model under external plane wave illumination;

[0008] Step 2: Set the plane wave intensity to obtain the field strength distribution inside the cavity of the electronic device model;

[0009] Step 3: Based on the field strength distribution inside the electronic device model, determine the weak points of the shielding electromagnetic effect;

[0010] Step 4: Establish an energy-selective surface structure comprising several slot resonant patches arranged in an array;

[0011] Step 5: Set the energy selective surface structure on the surface where the weak point of the shielding electromagnetic effect is located, and establish an energy selective surface protection structure model; compare the field strength at the weak point of the shielding electromagnetic effect in the energy selective surface protection structure model with the protection requirements to determine whether the energy selective surface structure meets the protection requirements.

[0012] Optionally, in step 4, each of the slot resonant patches is a square metal sheet, including one or more slots and diodes of the same number as the slots; each slot 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 several gaps on the slot resonant patch, the gaps are arranged symmetrically with respect to the center point of the slot resonant patch, the two symmetrical gaps have the same size, and the diodes on the gaps are also arranged in the same direction.

[0014] Optionally, when the electronic device model has multiple resonant frequency points, 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 fitted outside the second square ring slot. Each square ring slot is composed of four slots of the same size and four diodes, and the diodes in the middle positions of two parallel slots in each square ring slot are oriented in the same direction.

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

[0016]

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

[0018] Optionally, step 5 may also include: setting a field strength threshold in the 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 resonant patch and the operating frequency of the diode, and recalculate the field strength at that point; when the field strength at that 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 casing of the electronic device and pores on the surface of the electronic device; the electronic device model has an internal cavity, 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 the cavity of the electronic device model through the pores.

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

[0022]

[0023] In the formula, a is the radius of the pore, S is the area of ​​the pore, R is the distance from the test point in the cavity of the electronic device model to the pore, E is the field strength 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 illumination angle and frequency of the plane wave to obtain the field strength distribution of the cavity of the electronic device model under different illumination 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 100MHz to 6GHz.

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

[0027] This invention simplifies the modeling of electronic devices, calculates the weak points in their shielding effectiveness, and establishes an energy-selective surface (ESS) protective structure model by constructing an ESS structure. The electric field strength at these weak points is compared to determine whether the ESS structure meets the protection requirements of the electronic device. Furthermore, by changing the gap length and diode operating frequency within the ESS structure, the method automatically adjusts the ESS structure to ensure it meets the protection requirements of the electronic device. The method described in this invention allows for automatic adjustment of the required ESS structure based on the protection needs of the electronic device, enabling design for different protection requirements and achieving better protection effects. Moreover, the design process for the ESS structure is more convenient. Attached Figure Description

[0028] Figure 1 This is a flowchart of the adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to the present invention.

[0029] Figure 2 This is a schematic diagram of an electronic device model for the adaptive electromagnetic radiation suppression method in a high-intensity radiation field according to the present invention.

[0030] Figure 3 This is a diagram of the slit structure of the slit resonant patch in the adaptive electromagnetic radiation suppression method for devices in high-intensity radiation fields according to the present invention.

[0031] Figure 4 This is a structural diagram of the slot resonant patch for the adaptive electromagnetic radiation suppression method of the device in a high-intensity radiation field according to the present invention.

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

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

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] like Figure 1 As shown, this invention provides an adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field, the specific steps of which include:

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

[0039] In the modeling of electronic equipment within an aircraft, the transparent materials, fine internal structures, internal structures within enclosed metal components, and non-metallic patches within layered structures of the electronic equipment are ignored, resulting in a simplified electronic equipment model 1, as shown in Figure 1. Figure 2 As shown. The electronic device model includes: a metal casing of the electronic device and pores 11 on the surface of the electronic device. Therefore, the electronic device model 1 has an internal cavity, and the surface of the electronic device model 1 is provided with pores 11 to ensure that when the electronic device model 1 is in a high-intensity radiation field (HIRF), plane waves in the HIRF field can irradiate the pores 11 on the electronic device model 1 and then irradiate the cavity of the electronic device model 1 through the pores 11. The wave-transparent material includes: plastic and glass.

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

[0041] Based on the duration of radiation exposure to the electronic device, 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 illumination angle and frequency of the plane wave to obtain the field strength distribution within the cavity of the electronic device model 1 under different illumination angles and polarization conditions. The frequency range of the plane wave is selected according to the type of electronic device, with a maximum frequency not exceeding 18 GHz, and typically ranging from 100 MHz to 6 GHz.

[0042] Step 3: Determine the resonant frequency of the cavity inside the electronic device model.

[0043] Based on the field strength distribution inside the electronic device model 1 obtained in step 2, simulation calculations are performed on the inside of the electronic device model 1 to determine the weak points of the shielding electromagnetic effect, and then the resonant frequency at that point is obtained through simulation calculations.

[0044] The electromagnetic shielding effect is related to the field strength obtained from the internal cavity test of the electronic device model 1, as shown in Equation 1. When the electromagnetic shielding effect is weak, the field strength inside the electronic device model 1 is closer to the external field strength. Therefore, the internal cavity at the aperture 11 of the electronic device model 1 is the weak point of the electromagnetic shielding effect.

[0045]

[0046] In the formula, E is the field strength at any test point in the cavity of the electronic device model when it is unshielded, that is, the field strength environment in which the electronic device model is located; E” is the field strength at any test point in the cavity of the electronic device model when it is shielded, that is, the field strength in the cavity of the electronic device model; SSE is the shielding effectiveness.

[0047] Under the influence of plane waves, charge deposition occurs at the edge of aperture 11 in electronic device model 1 due to the charge layer phenomenon on the metal surface. Aperture 11 can then be considered equivalent to a dipole antenna emitting electromagnetic energy into the cavity of electronic device model 1, creating a complex electromagnetic environment. Therefore, the field strength E” in the cavity at aperture 11 of electronic device model 1 can be expressed as:

[0048]

[0049] In the formula, a is the radius of the aperture 11, S is the area of ​​the aperture 11, R is the distance from the test point in the cavity of the electronic device model to the aperture, E is the field strength 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 the energy-selective surface structure.

[0051] For the resonance 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. As Figure 5 shown, the energy selective surface structure 3 includes a number 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 requirement, the slot resonant patch 2 includes one or several slots 21 and the same number of diodes 22 as the number of slots 21. As Figure 3 shown, each of the slots 21 is parallel to the edge of the slot resonant patch 2, and one diode 22 is provided at the center position of the slot 21, so that the slot resonant patch 2 forms a passive structure; the conduction direction of the diode 22 is perpendicular to the length direction of the slot 21.

[0053] Specifically, as Figure 3 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 provided at the center position of the slot resonant patch 2. At this time, the energy selective surface structure 3 composed of a number of slot resonant patches 2 is suitable for single-frequency point shielding.

[0054] Specifically, as Figure 4 shown, when there are several slots 21 on the slot resonant patch 2, the several 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 sizes of two relatively symmetric slots 21 (that is, the length directions of the slots 21 are the same and the distances between the slots 21 and the center point of the slot resonant patch 2 are the same) are the same, and the setting directions of the diodes 22 on the slots 21 are also the same, ensuring that the diodes 22 can form a path for the slots 21 on the slot resonant patch 2.

[0055] In a preferred embodiment, when there are multiple resonant frequencies in the electronic device model 1, an energy selective surface structure 3 with dual-frequency or even multi-frequency working characteristics needs to be designed. The several slots 21 on each slot resonant patch 2 in the energy selective surface structure 3 are arranged in a "hui" character shape, as Figure 4 shown, that is, 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 that of the second square ring slot, and the first square ring slot is sleeved outside the second square ring slot. Each square ring slot is composed of 4 slots 21 with the same size and 4 diodes 22; the directions of the diodes 22 provided at the middle positions of the two mutually parallel slots 21 in each square ring slot are the same. 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 slit 21 is greater than 1, i.e., L / w > 1. The length L of the slit 21 is half the wavelength corresponding to the resonant frequency, which can be expressed as:

[0057]

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

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

[0060]

[0061] In the formula, 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 function of the energy selective surface structure 3 in a high-intensity radiation field.

[0063] By jointly simulating the equivalent circuit model with the energy selective surface energy structure, the electromagnetic protection characteristics of the energy selective surface are obtained.

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

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

[0066] The energy selective surface structure 3 from step 4 is placed on the surface where the aperture 11 is located in the electronic device model 1, thus establishing an energy selective surface protection structure model. The energy selective surface protection structure model is placed in a plane wave, and a full-wave simulation of the loaded circuit is performed. The shielding effectiveness is evaluated at the weak points of the original electronic device model 1 in the energy selective surface protection structure model, and the field strength at these points 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 gap 21 on the gap 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 a high-intensity radiation field.

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

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

Claims

1. A method for adaptive electromagnetic radiation suppression of equipment in a high-intensity radiation field, characterized in that, The specific steps include: Step 1: Establish an electronic device model under external plane wave illumination; Step 2: Set the plane wave intensity to obtain the field strength distribution inside the cavity of the electronic device model; Step 3: Based on the field strength distribution inside the electronic device model, determine the weak points of the shielding electromagnetic effect; Step 4: Establish an energy selective surface structure comprising several slot resonant patches arranged in an array; each slot resonant patch is a square metal sheet, including one or more slots and diodes of the same number as the slots; each slot is parallel to the edge of the slot resonant patch, and a diode is provided at the center of each slot; the conduction direction of the diode is perpendicular to the length direction of the slot. Step 5: Set the energy selective surface structure on the surface where the weak point of the shielding electromagnetic effect is located, and establish an energy selective surface protection structure model; compare the field strength at the weak point of the shielding electromagnetic effect in the energy selective surface protection structure model with the protection requirements to determine whether the energy selective surface structure meets the protection requirements. Set the field strength threshold in the 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 resonant patch and the operating frequency of the diode, and recalculate the field strength at that point; when the field strength at that point is less than the field strength threshold, it means that the energy selective surface structure meets the protection requirements.

2. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 1, characterized in that, When there are several gaps on the slot resonant patch, the gaps are arranged symmetrically with respect to the center point of the slot resonant patch. The two symmetrical gaps have the same size, and the diodes on the gaps are also arranged in the same direction.

3. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 1, characterized in that, When the electronic device model has multiple resonant frequency points, 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 fitted outside the second square ring slot. Each square ring slot is composed of four slots of the same size and four diodes, and the diodes placed at the middle position of two parallel slots in each square ring slot are in the same direction.

4. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 3, characterized in that, The ratio of the length L to the width w of the slit is greater than 1, and the length L of the slit is half the wavelength corresponding to the resonant frequency, which can be expressed as: In the formula, f is the resonant frequency at the weak point of the shielding electromagnetic effect, and v is the wave speed of the plane wave.

5. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 1, characterized in that, In step 1, the electronic device model includes: a metal casing of the electronic device and pores on the surface of the electronic device; the electronic device model has a cavity inside, 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 the cavity of the electronic device model through the pores.

6. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 5, characterized in that, Step 3 also includes: the weak point of the shielding electromagnetic effect is the inner cavity at the aperture of the electronic device model, and the field strength E'' of the inner cavity at the aperture of the electronic device model can be expressed as: In the formula, a is the radius of the pore, S is the area of ​​the pore, R is the distance from the test point in the cavity of the electronic device model to the pore, E is the field strength 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.

7. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 1, characterized in that, In step 2, the electronic device model is simulated by changing the illumination angle and frequency of the plane wave to obtain the field strength distribution of the cavity of the electronic device model under different illumination angles and polarization conditions; wherein the frequency of the plane wave does not exceed 18 GHz.

8. The adaptive electromagnetic radiation suppression method for equipment in a high-intensity radiation field according to claim 7, characterized in that, The plane wave has a frequency range of 100MHz to 6GHz.

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