Flexible energy selective surface for suppressing electromagnetic wave bioeffects

Abstract

The present application relates to the technical field of electromagnetic wave, in particular to a flexible energy selective surface for inhibiting electromagnetic wave biological effect, which comprises a medium layer and a structure layer arranged on the upper surface of the medium layer; the structure layer is composed of square inscribed circle structure units and Jerusalem crosses inside the structure units; the end of the Jerusalem cross is provided with a rectangular sheet; a diode is arranged in the gap between the square inscribed circle structure unit and the rectangular sheet; the flexible energy selective surface is divided into a plurality of periodically arranged structure layers; the flexible energy selective surface provided by the present application has an insertion loss of less than 3dB in the frequency range of 5.1-6.3GHz under the condition of low-power electromagnetic wave incidence; the flexible energy selective surface provides ultra-wideband protection against high-power electromagnetic waves in the frequency range of 0.1-8.5GHz, and has important application value in the field of electromagnetic protection.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave technology applications, and more particularly to a flexible energy-selective surface for suppressing the biological effects of electromagnetic waves. Background Technology

[0002] In recent years, the impact of high-power microwaves has received increasing attention and in-depth research. The effects of high-power electromagnetic waves can be categorized into biological and non-biological effects, depending on the target of the radiation. While the use of high-power electromagnetic waves in electronic devices does not cause biological effects, it can still harm living organisms. Long-term exposure to high-power electromagnetic waves can impair the activity of living organisms; these high-intensity electromagnetic waves can cause burns or even immediate death. The electromagnetic waves emitted by solar-powered space stations are high-power electromagnetic waves, and due to their biological effects, it is essential to protect living organisms in the surrounding environment. Traditional electromagnetic protection methods include frequency-selective surfaces (FSS) and pin limiters; however, these methods have inherent limitations. While FSSs can effectively defend against out-of-band EMI signals, they cannot prevent interference signals within the operating frequency band. Furthermore, traditional protection methods cannot distinguish between high-power electromagnetic waves and basic wireless communication signals; the former may damage communication electronic equipment.

[0003] To overcome the limitations of traditional electromagnetic protection methods, researchers have introduced adaptive defense devices that can be directly triggered by high-power electromagnetic waves (HPM). In 2014, Werner A. Arriola proposed an energy-sensitive bandpass filter limiter. This innovative approach achieves adaptive protection against strong electromagnetic radiation by integrating a diode onto a metal structure. The in-band loss of the incident wave is controlled based on the magnitude of the induced voltage on the metal structure, thus achieving adaptive protection against strong electromagnetic radiation. However, it is worth noting that this method has not yet been experimentally verified. Subsequently, due to the nonlinear response of PIN diodes to input power, researchers shifted their focus to energy selective surfaces (ESS). Over the past few decades, several ESS have been proposed and related papers published. However, most of these studies have mainly focused on high-power microwave protection in the L-band and S-band, and their protection bandwidth is relatively narrow. To extend the protection bandwidth, researchers have attempted to design ESS as multi-layered structures, but these structures lack conformal performance. Therefore, researching a conformal ultrawideband ESS for high-power electromagnetic protection remains a significant challenge. Summary of the Invention

[0004] To address the problem that existing energy selective surfaces cannot effectively protect living organisms in the surrounding environment, this invention provides a flexible energy selective surface for suppressing the biological effects of electromagnetic waves. The conformal energy selective surface of this invention has an insertion loss of less than 3dB in the frequency range of 5.1 to 6.3 GHz; the flexible energy selective surface provides ultra-wideband protection against high-power electromagnetic waves in the frequency range of 0.1 to 8.5 GHz.

[0005] Flexible energy-selective surfaces for suppressing the biological effects of electromagnetic waves include:

[0006] A dielectric layer and a structural layer disposed on the upper surface of the dielectric layer;

[0007] The structural layer is composed of square inscribed circle structural units and Jerusalem crosses inside them;

[0008] The ends of the Jerusalem Cross are each provided with a rectangular plate;

[0009] A diode is provided in the gap between the square inscribed circle structural unit and the rectangular piece;

[0010] The flexible energy selective surface is divided into several periodically arranged structural layers.

[0011] Preferably, the dielectric layer is made of polyimide with a relative permittivity of 2.8 and a loss tangent of 0.02; and

[0012] The thickness of the dielectric layer is 0.2 mm, the scanning range is 0.1-0.4 mm, and the scanning step size is 0.1 mm.

[0013] Preferably, the positive terminals of all the diodes are oriented towards the center of the Jerusalem Cross.

[0014] Preferably, the square inscribed circle structural unit includes: a square structure and a circular structure, wherein,

[0015] The side length of the square structure is 6.5mm;

[0016] The arm of the Jerusalem Cross is 1.53 mm long;

[0017] The rectangular piece is 2.6 mm long;

[0018] The width of the rectangular piece is 0.65mm;

[0019] The thickness of the square structure, the circular structure, and the Jerusalem cross is all 0.1 mm;

[0020] The radius of the circular structure is 3.25 mm.

[0021] Preferably, the side length scanning range of the square structure is 5-7 mm, and the scanning step size is 0.5 mm;

[0022] The scanning range for the length of the rectangular area is 2-3 mm, and the scanning step size is 0.1 mm.

[0023] Preferably, the diode is a PIN diode.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: the flexible energy selective surface provided by the present invention has an insertion loss of less than 3dB in the frequency range of 5.1 to 6.3 GHz under low power electromagnetic wave incident conditions; the flexible energy selective surface provides ultra-wideband protection against high power electromagnetic waves in the frequency range of 0.1-8.5 GHz, which has important application value in the field of electromagnetic protection. Attached Figure Description

[0025] Figure 1 This is a front view of the structure of the present invention;

[0026] Figure 2 This is a side view of the structure of the present invention;

[0027] Figure 3 This is a simulation model diagram of the diode startup voltage of the present invention;

[0028] Figure 4 This is a schematic diagram of the coupling voltage across the diode under different electric field strengths according to the present invention;

[0029] Figure 5 When a low-power electromagnetic wave is incident in this invention, S 21 Schematic diagram of the curve;

[0030] Figure 6 When the high-power electromagnetic wave of the present invention is incident, S 21 Schematic diagram of the curve;

[0031] Figure 7 This is a schematic diagram of the energy-selective surface under bending conditions in this invention;

[0032] Figure 8 The S-value of the energy-selective surface under different bending radii when low-power electromagnetic waves are incident in this invention. 21 Schematic diagram of the curve;

[0033] Figure 9 The S-value of the energy-selective surface under different bending radii when high-power electromagnetic waves are incident in this invention. 21 Schematic diagram of the curve;

[0034] Figure 10 Figure A is a physical representation of the present invention;

[0035] Figure 11 Figure B is a physical representation of the present invention;

[0036] Figure 12 This is a diagram illustrating the testing process of the present invention;

[0037] Figure 13 This is a comparison chart of simulation and physical test results when low-power electromagnetic waves are incident in this invention;

[0038] Figure 14 This is a comparison chart of simulation and physical test results when high-power electromagnetic waves are incident in this invention. Detailed Implementation

[0039] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0041] The simulation and measurement results of this invention show good consistency. Compared with previous research, the flexible energy selective surface of this invention has lower insertion loss and a wider operating bandwidth. The energy selective surface designed in this invention has an insertion loss of only 0.1 dB at 5.8 GHz, which happens to be an important frequency for communication. Therefore, the energy selective surface proposed in this invention has significant application value in the field of electromagnetic protection.

[0042] like Figures 1-2 As shown, the side length 'a' of the square structure is 6.5 mm;

[0043] The length b of the half arm of the Jerusalem Cross is 1.53 mm;

[0044] The length c of the rectangular piece is 2.6 mm;

[0045] The width d of the rectangular piece is 0.65mm;

[0046] The thickness w of the square structure, the circular structure, and the Jerusalem cross is 0.1 mm.

[0047] The radius r of the circular structure is 3.25 mm;

[0048] The thickness of the dielectric layer is 0.2 mm (the thickness of the dielectric layer was determined through simulation; when the thickness is 0.2 mm, the protective bandwidth of the flexible energy selection surface is the widest, so a thickness of 0.2 mm was chosen).

[0049] The diode selected in this embodiment of the invention is a PIN diode, specifically an SMP1345-079LF diode, which exhibits low insertion loss under forward bias and effective shielding under zero bias. Based on the S-parameters (referring to the S-parameters of a PIN diode, i.e., the diode's S...) in the datasheet... 21 The S-parameters of the diode are provided in the diode's datasheet. By importing the diode's S-parameters into the ADS software for simulation optimization, the equivalent circuit value of the PIN diode can be obtained. That is, the PIN diode used in this paper can be equivalent to a capacitor with a capacitance of 0.15pF when low-power electromagnetic waves are incident, and equivalent to a resistor of 2Ω when high-power electromagnetic waves are incident. Thus, when simulating in the CST software, the equivalent circuit value of the diode can be directly input for simulation. The equivalent circuit value of the lumped element was extracted using the Advanced Design System software.

[0050] When high-power electromagnetic waves are incident (the diode is in a conducting state when high-power electromagnetic waves are incident, and the impedance of the energy selective surface decreases, thus reflecting the electromagnetic waves incident on the energy selective surface; reflection means that the electromagnetic waves incident on the energy selective surface do not enter the interior of the energy selective surface but are reflected directly on the surface), the diode is in a conducting state and reflects the incident electromagnetic waves. In this case, the diode can be equivalent to a resistor with a resistance of 2Ω. When low-power electromagnetic waves are incident, the diode cannot conduct, and the incident electromagnetic waves will pass through the flexible energy selective surface. In this case, the diode will be equivalent to a capacitor with a capacitance C. OFF =0.15pF.

[0051] The startup voltage of an energy-selective surface depends on the coupling voltage across the PIN diode. Therefore, accurately simulating the coupling voltage is essential. Figure 3 The diagram shows a simulation model of the PIN diode's startup threshold. It uses a vertically polarized plane wave incident on the energy selective surface to simulate the metal gap coupling voltage of the designed energy selective surface. Because the structure is symmetrical, the coupling voltage amplitudes obtained from simulating the top and bottom diodes are the same but in opposite directions. This also applies to the left and right diodes. Therefore, the startup characteristics of the designed energy selective surface can be analyzed by simulating the coupling voltage of the top diode.

[0052] A time-domain simulation was performed on the PIN diode startup threshold model to evaluate the coupling voltage across the diode under different field strengths. Figure 4 The graph shows the variation of the coupling voltage of the PIN diode. When the incident electromagnetic field strength is less than 600 V / m, the voltage coupling across the diode is very low, and the diode cannot be excited, failing to reach the energy-selective surface protection threshold. However, at an electric field strength of 800 V / m, the diode is observed to conduct, achieving the purpose of electromagnetic protection.

[0053] It should be noted that in this invention, high-power electromagnetic waves correspond to environments with peak electric field strength exceeding 800V / m, while environments with peak electric field strength exceeding 800V / m correspond to low-power electromagnetic waves.

[0054] like Figure 5 - As shown in Figure 6, the S-type of the flexible energy-selective surface 21 The simulation results, as shown in the graph, indicate that under low-power electromagnetic wave incident conditions, the passband bandwidth of -3dB lies within the frequency range of 5.1-6.3GHz, and the insertion loss at 5.8GHz is only 0.1dB. When high-power microwave (HPM) is incident, the PIN diode will conduct, and at this time, a bandwidth below -10dB can be observed to reach 8.4GHz (0.1-8.5GHz).

[0055] The flexible energy selective surface of this invention can achieve conformal functionality. To investigate the influence of the degree of curvature on the performance of the proposed energy selective surface, the S-parameters of energy selective surfaces with different curvature radii were simulated and analyzed under low-power and high-power electromagnetic wave incident conditions. Figure 7 The diagram shows a curved, flexible energy-selective surface element structure, where R represents the bending radius. Simulation results are shown below. Figures 8-9 Simulation curves show that under low-power incident conditions, the resonant frequency shifts to a lower frequency as the bending radius increases, while the -3dB bandwidth narrows. However, under high-power electromagnetic wave incident conditions, the protection bandwidth expands with increasing bending radius. Furthermore, when R = 4mm, the S21 < -10dB bandwidth reaches 9.2GHz (0.1-9.3GHz). Overall, the flexible energy selective surface designed in this invention exhibits good conformal performance.

[0056] In one embodiment, to experimentally verify the performance of the flexible energy selective surface of the present invention, a 15x15 array design unit with a size of 150mm*150mm was fabricated, such as... Figures 10-11 As shown, a PIN diode (SMP1345-079LF) was soldered onto a polyimide substrate, and a periodic structure was printed on the front side. The designed energy-selective surface was measured using the free-space method, and the experimental test system is shown below.Figure 12 As shown, two broadband horn antennas, each approximately 21 cm in diameter, were placed on either side of the energy selective surface, which was positioned in the center of the absorbing wall. The distance between the energy selective surface and the horn antennas was approximately 2 meters. Due to environmental limitations, the PIN diodes were replaced with 2-ohm resistors to complete the testing of the energy selective surface under high-power incident conditions.

[0057] Figures 13-14 The graph shows a comparison between the test structure and the simulation results. The comparison reveals some differences between the test and simulation structures. Specifically, the frequency point of minimum insertion loss shifts to a lower frequency, and the -3dB bandwidth is smaller than the bandwidth obtained from the simulation. Furthermore, the shielding bandwidth becomes narrower under high-power incident conditions. There are two possible reasons for these differences. First, errors in the testing process and physical fabrication; second, the presence of two horn antennas prevents the incident and reflected waves from being perpendicular to the energy-selective surface, leading to some degree of error in the measurement system. Despite these differences, the trends observed in the experimental results are quite similar to those predicted by the simulation.

[0058] In summary, this invention provides a conformal flexible energy selective surface (ESS) that offers ultra-wideband protection. The transmission performance of the ESS is comprehensively discussed, demonstrating that the designed ESS allows operating signals to pass through with low insertion loss in the 5.1–6.3 GHz range under low-power electromagnetic environments. High-power electromagnetic waves are blocked from entering the device due to transmission attenuation exceeding 10 dB in the 0.1–8.5 GHz frequency range. Furthermore, the bending capability of the flexible energy selective surface is verified through simulation. The actual measurement results of the designed flexible energy selective surface are consistent with the simulation results, indicating that the flexible energy selective surface can serve as an adaptive defense against high-power electromagnetic waves (HPM). The proposed ESS is an ideal solution to avoid the biological effects of high-power electromagnetic waves.

[0059] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0060] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A flexible energy-selective surface for suppressing the biological effects of electromagnetic waves, characterized in that, include: A dielectric layer and a structural layer disposed on the upper surface of the dielectric layer; The structural layer is composed of square inscribed circle structural units and Jerusalem crosses inside them; The ends of the Jerusalem Cross are each provided with a rectangular plate; A diode is provided in the gap between the square inscribed circle structural unit and the rectangular piece; The flexible energy selective surface is divided into several periodically arranged structural layers.

2. The flexible energy-selective surface for suppressing the biological effects of electromagnetic waves according to claim 1, characterized in that, The dielectric layer is made of polyimide with a relative permittivity of 2.8 and a loss tangent of 0.02; and The thickness of the dielectric layer is 0.2 mm, the scanning range is 0.1-0.4 mm, and the scanning step size is 0.1 mm.

3. The flexible energy-selective surface for suppressing the biological effects of electromagnetic waves according to claim 1, characterized in that, The positive terminals of all the diodes are oriented towards the center of the Jerusalem Cross.

4. The flexible energy-selective surface for suppressing the biological effects of electromagnetic waves according to claim 1, characterized in that, The square inscribed circle structural unit includes: a square structure and a circular structure, wherein... The side length of the square structure is 6.5mm; The arm of the Jerusalem Cross is 1.53 mm long; The rectangular piece is 2.6 mm long; The width of the rectangular piece is 0.65mm; The thickness of the square structure, the circular structure, and the Jerusalem cross is all 0.1 mm; The radius of the circular structure is 3.25 mm.

5. The flexible energy-selective surface for suppressing the biological effects of electromagnetic waves according to claim 4, characterized in that, The scanning range of the side length of the square structure is 5-7mm, and the scanning step size is 0.5mm; The scanning range for the length of the rectangular area is 2-3 mm, and the scanning step size is 0.1 mm.

6. The flexible energy-selective surface for suppressing the biological effects of electromagnetic waves according to claim 1, characterized in that, The diode is a PIN diode.

Images