Frequency-agile absorptive and transmissive metasurfaces and radomes

Abstract

The present application belongs to the technical field of multifunctional radome, and particularly relates to a frequency agile absorbing and penetrating integrated electromagnetic metasurface and radome, which comprises a plurality of periodically arrayed basic units, wherein the basic unit comprises two oppositely arranged wave-penetrating layer and wave-absorbing layer; the wave-penetrating layer comprises a wave-penetrating dielectric substrate and wave-penetrating metal foil layers I and II arranged on both sides of the wave-penetrating dielectric substrate; the wave-penetrating metal foil layer I comprises a plurality of metal spiral lines, and the wave-penetrating metal foil layer II comprises a metal foil, wherein the metal foil is provided with an annular gap and a plurality of rectangular gaps distributed around the annular gap; the wave-absorbing layer comprises a wave-absorbing dielectric substrate and wave-absorbing metal foil layers I and II arranged on both sides of the wave-absorbing dielectric substrate; the present application has both wave-penetrating communication and wave-absorbing isolation functions, and has a frequency agile wave-absorbing function, and has a better wave-absorbing effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of multifunctional radomes, and particularly relates to a frequency agile absorbing and transmitting integrated electromagnetic super surface and radome. BACKGROUND

[0002] The antenna of the front end of a modern wireless communication and radar system is an indispensable component in the entire system. A new type of multifunctional electromagnetic super material radome provides physical protection for the antenna covered by the radome, prevents adverse weather such as rain and snow from affecting it, and at the same time, provides electromagnetic protection, allowing the antenna covered by the radome to freely communicate without loss in its own communication frequency band, and to realize isolation from the external electromagnetic environment in the absorbing frequency band, that is, in the absorbing frequency band outside the antenna communication frequency band, the external electromagnetic wave is difficult to interfere with or detect the antenna covered by the radome.

[0003] The frequency agility of the absorbing and transmitting integrated electromagnetic super material refers to the material's ability to dynamically adjust its operating frequency and quickly switch between absorbing or transmitting electromagnetic waves in different frequency bands to adapt to the needs of complex electromagnetic environments. The core mechanism is based on the reconfigurability of electromagnetic super materials, which changes the material's electromagnetic parameters (such as permittivity and permeability) through external excitation or intelligent control means to achieve response adjustment for specific frequencies. Achieving frequency agility can better adapt to the needs of dynamic electromagnetic environments, improve anti-interference and concealment, and optimize wideband performance. SUMMARY

[0004] The technical problem to be solved by the application is to provide a frequency agile absorbing and transmitting integrated electromagnetic super surface and radome that has both wave-transparent communication and wave-absorbing isolation functions, and has a frequency agile absorbing function, and has better wave-absorbing effect.

[0005] The embodiment of the application provides a frequency agile absorbing and transmitting integrated electromagnetic super surface, which comprises a plurality of periodically arrayed basic units, the basic unit comprising two oppositely arranged wave-transparent layers and wave-absorbing layers.

[0006] The wave-transparent layer comprises a wave-transparent dielectric substrate and wave-transparent metal foil layers I and II arranged on both sides of the wave-transparent dielectric substrate.

[0007] The wave-transparent metal foil layer I comprises a plurality of metal spiral lines, and the wave-transparent metal foil layer II comprises a metal foil, the metal foil being provided with an annular gap and a plurality of rectangular gaps distributed around the annular gap.

[0008] The wave-absorbing layer comprises a wave-absorbing dielectric substrate and wave-absorbing metal foil layers I and II arranged on both sides of the wave-absorbing dielectric substrate.

[0009] The wave-absorbing metal foil layer I comprises closed loop metal wires I, a plurality of resonant structures I are arranged on the closed loop metal wires I, the resonant structure I comprises a connecting wire I connected to the closed loop metal wire I and an open metal wire connected to the connecting wire I; and a varactor diode is arranged on the connecting wire I and / or the open metal wire.

[0010] The wave-absorbing metal foil layer II comprises closed loop metal wires II, a plurality of resonant structures II are arranged on the closed loop metal wires II, the resonant structure II comprises a connecting wire II connected to the closed loop metal wire II and a U-shaped metal wire connected to the connecting wire II; a varactor diode is arranged on the connecting wire II, and a resistor is arranged on the U-shaped metal wire.

[0011] Preferably, the wave-transparent layer and the wave-absorbing layer are air.

[0012] Preferably, the wave-transparent layer and the wave-absorbing layer are rectangular, and the closed loop metal wires I and the closed loop metal wires II are rectangular.

[0013] Preferably, the number of the metal spiral wires is 4, and the metal spiral wires are arrayed on the surface of the wave-transparent dielectric substrate, and the metal spiral wires are rectangular path spiral structures.

[0014] Preferably, the shape of the ring-shaped slot is rectangular.

[0015] Preferably, the closed loop metal wires I and the closed loop metal wires II are rectangular, the number of the resonant structures I is 4, and the resonant structures I are respectively located on four edges of the closed loop metal wires I, and the number of the resonant structures II is 4, and the resonant structures II are respectively located on four edges of the closed loop metal wires II.

[0016] Preferably, the open metal wire is a rectangle with an opening, and the opening is close to the center of the closed loop metal wire I.

[0017] Preferably, the varactor diode is arranged on the connecting wire I.

[0018] Preferably, a connecting through hole is arranged on the wave-absorbing dielectric substrate, and the connecting through hole connects and conducts the open metal wire and the U-shaped metal wire.

[0019] The embodiment of the present application provides an antenna cover, which comprises the frequency-agile wave-absorbing and wave-transparent electromagnetic metasurface.

[0020] The present application has the advantages that the wave-transparent communication metasurface structure and the wave-absorbing isolation metasurface structure are organically combined together to form an integrated multifunctional antenna cover structure. The printed circuit board process loaded with varactor diodes and lumped resistors can realize the agility of the wave-absorbing frequency band, so that the metasurface antenna cover can effectively cope with the complex electromagnetic environment with variable frequency bands. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Structure diagram of the wave-transparent metal foil layer I of Example 1 of the present application.

[0022] Figure 2 Structure diagram of the wave-transparent metal foil layer I of Example 1 of the present application.

[0023] Figure 3 Structure diagram of the wave-transparent metal foil layer II of Example 1 of the present application.

[0024] Figure 4 Structure diagram of the wave-absorbing metal foil layer I of Example 1 of the present application.

[0025] Figure 5 Structure diagram of the wave-absorbing metal foil layer II of Example 1 of the present application.

[0026] Figure 6 Transmission coefficient of the structure of Example 1 of the present application.

[0027] Figure 7 Reflection coefficient of the structure of Example 1 of the present application.

[0028] Figure 8 Transmission / reflection characteristics of the structure of Example 1 of the present application.

[0029] Figure 9 Transmission / reflection characteristics of the structure of Comparative Example 1 of the present application.

[0030] Figure 10 Transmission / reflection characteristics of the structure of Comparative Example 2 of the present application.

[0031] Figure 11 Transmission / reflection characteristics of the structure of Comparative Example 3 of the present application.

[0032] Figure 12 Transmission / reflection characteristics of the structure of Comparative Example 4 of the present application.

[0033] In the drawings, 1 wave-transparent layer, 11 wave-transparent metal foil layer I, 111 metal spiral, 12 wave-transparent dielectric substrate, 13 wave-transparent metal foil layer II, 131 metal foil, 132 annular slit, 133 rectangular slit;

[0034] 2 wave-absorbing layer, 21 wave-absorbing metal foil layer I, 211 closed-loop metal wire I, 212 connecting wire I, 213 open metal wire, 2131 connecting through-hole, 2132 opening, 214 varactor diode, 22 wave-absorbing dielectric substrate; 23 wave-absorbing metal foil layer II, 231 closed-loop metal wire II, 232 connecting wire II, 233 U-shaped metal wire, 234 resistor. DETAILED DESCRIPTION

[0035] Example 1

[0036] AsFigures 1-5 The frequency agile absorbing and transmitting integrated electromagnetic metasurface comprises a plurality of periodically arrayed basic units, and the basic unit comprises two oppositely arranged wave-transparent layer 1 and wave-absorbing layer 2.

[0037] The wave-transparent layer 1 comprises a wave-transparent medium substrate 12 and wave-transparent metal foil layers I 11 and II 13 arranged on both sides of the wave-transparent medium substrate 12.

[0038] The wave-transparent metal foil layer I 11 is a plurality of metal spiral lines 111, and the wave-transparent metal foil layer II 13 comprises a metal foil 131, wherein the metal foil 131 is provided with an annular gap 132 and a rectangular gap 133 distributed around the annular gap 132.

[0039] The wave-absorbing layer 2 comprises a wave-absorbing medium substrate 22 and wave-absorbing metal foil layers I 21 and II 23 arranged on both sides of the wave-absorbing medium substrate 22.

[0040] The wave-absorbing metal foil layer I 21 comprises a closed loop metal line I 211, wherein a plurality of resonant structures I are arranged on the closed loop metal line I 211, the resonant structure I comprises a connecting line I 212 connected to the closed loop metal line I 211 and an open metal line 213 connected to the connecting line I 212, and a variable capacitance diode 214 (the number is 4) is arranged on the connecting line I 212.

[0041] The wave-absorbing metal foil layer II 23 comprises a closed loop metal line II 231, wherein a plurality of resonant structures II are arranged on the closed loop metal line II 231, the resonant structure II comprises a connecting line II 232 connected to the closed loop metal line II 231 and a U-shaped metal line 233 connected to the connecting line II 232, a variable capacitance diode 214 (that is, after the connecting line II 232 is cut off, the variable capacitance diode 214 is placed at the cut-off position and connected to the cut-off connecting line II 232, the number is 4) is arranged on the connecting line II 232, and a resistor 234 (that is, after the U-shaped metal line 233 is cut off, the resistor 234 is placed at the cut-off position and connected to the cut-off U-shaped metal line 233, the resistor 234 is arranged on the two U-shaped arms of the U-shaped metal line 233, the number of the U-shaped metal line 233 is 4, and the total number of the resistors 234 is 8) is arranged on the U-shaped metal line 233.

[0042] The wave-transparent layer 1 realizes the wave-transparent function, the wave-absorbing layer 2 realizes the wave-absorbing function, and both the wave-transparent layer 1 and the wave-absorbing layer 2 are prepared by using a printed circuit board process.

[0043] The wave-transparent medium substrate 12 and the wave-absorbing medium substrate 22 are both insulating materials, the thickness is 0.3-1 mm, and the relative dielectric constant is 2.2-6.

[0044] The air is arranged between the wave-transparent layer 1 and the wave-absorbing layer 2, and the distance between the two is 5-20 mm.

[0045] The wave-transparent layer 1 and the wave-absorbing layer 2 are rectangular, and the closed loop metal wire I 211 and the closed loop metal wire II 231 are rectangular, preferably square.

[0046] The number of the metal spiral wire 111 is 4, which is arrayed on the surface of the wave-transparent medium substrate 12, and the metal spiral wire 111 is a rectangular path spiral structure, that is, a plurality of fold lines are bent at 90° to form a rectangle, the length of the rectangle is 3-6 mm, the width is 2-5 mm, and the line width is 0.1-0.5 mm.

[0047] The shape of the ring-shaped gap 132 is rectangular, preferably square, and the length is 1-5 mm. The length of the rectangular gap 133 is 2-5 mm, and the width is 1-5 mm.

[0048] The closed loop metal wire I 211 and the closed loop metal wire II 231 are rectangular, the number of the resonant structure I is 4, which is arranged on the four edges of the closed loop metal wire I 211, and the number of the resonant structure II is 4, which is arranged on the four edges of the closed loop metal wire II 231.

[0049] The open metal wire 213 is a rectangle with an opening 2132, and the opening 2132 is close to the center of the closed loop metal wire I 211.

[0050] The connecting line I 212 is provided with a varactor diode 214.

[0051] The wave-absorbing medium substrate 22 is provided with a connecting through hole 2131, the connecting through hole 2131 connects and conducts the open metal wire 213 and the U-shaped metal wire 233, the meaning of conducting is that the open metal wire 213 and the U-shaped metal wire 233 are electrically connected, which can be realized by a metal through hole, preferably the connecting through hole 2131 connects and conducts the end of the open metal wire 213 and the end of the U-shaped metal wire 233, and the diameter of the connecting through hole 2131 is 0.1-0.5 mm.

[0052] The closed loop metal wire I 211 and the closed loop metal wire II 231 are square, and the side length is the same as that of the wave-transparent medium substrate 12 and the wave-absorbing medium substrate 22.

[0053] The wave-transparent metal foil layer I 111 and the wave-absorbing metal foil layer II 23 are oppositely arranged.

[0054] The wave-transparent medium substrate 12 and the wave-absorbing medium substrate 22 are square, and the side length is 5-20 mm.

[0055] The linewidths of the metal spiral wire 111, closed-loop metal wire I 211, connecting wire I 212, open metal wire 213, closed-loop metal wire II 231, connecting wire II 232, and U-shaped metal wire 233 are 0.1–0.5 mm. The thicknesses of the wave-transparent metal foil layer I 11, wave-transparent metal foil layer II 13, wave-absorbing metal foil layer I 21, and wave-absorbing metal foil layer II 23 are 0.017 mm–0.035 mm.

[0056] The open metal wire 213 is a rectangle with an opening 2132, the length of which is 3mm to 8mm and the width of which is 0.5mm to 2mm. The width of the opening is 0.5mm to 1mm and the wire width is 0.1mm to 0.5mm.

[0057] The varactor diode 214 has a capacitance range of 0.2pF to 1pF, an inductance range of 0.3nH to 1nH, and a parasitic resistance range of 5Ω to 20Ω. The resistor 234 has a resistance range of 100Ω to 500Ω.

[0058] This invention provides an antenna radome, including the aforementioned frequency-agile, permeable, integrated electromagnetic metasurface.

[0059] Example 2

[0060] The transmission coefficient of the structure in Example 1 was measured, and the results are as follows: Figure 6 As shown, by Figure 6 It can be seen that when the capacitance value of the varactor diode 214 changes from 0.3pF to 0.9pF in 0.1pF increments, its transmission frequency band ( The GHz band remains unchanged at 15.54 GHz to 17.25 GHz.

[0061] The reflection coefficient of the structure in Example 1 was measured, and the results are as follows: Figure 7 As shown, by Figure 7 It can be seen that when the capacitance value of the varactor diode 214 changes from 0.3pF to 0.9pF in 0.1pF increments, its absorption frequency band ( The highest absorption frequency in the spectrum changes from 13.65 GHz to 12.97 GHz, then to 12.72 GHz, then to 12.45 GHz, then to 12.29 GHz, and finally to 12.11 GHz. It can be seen that when the capacitance value is small, a change of 0.1 pF in the capacitance value results in a significant change in the absorption frequency band.

[0062] Comparative Example 1

[0063] Based on Example 1, the metal spiral 111 and rectangular slit 133 of the wave-transparent layer 1 are removed, while the other structures remain the same as in Example 1.

[0064] Comparing the transmission / reflection characteristics of the structure of Example 1 (i.e., structural unit 00) and Comparative Example 1 (i.e., structural unit 01), it is found that Figures 8-9 .

[0065] As can be seen from Figures 8-9 , the structural unit of the rectangular slot and the metal spiral line does not increase any cost. However, at the high frequency end of the wave-absorbing frequency band, the S parameter near the frequency point marked in the figure shows that the wave-absorbing effect of Example 1 is better. In the wave-absorbing frequency band, the rectangular slot and the metal spiral line are combined to form a series resonance, which works together with the series resonance formed by the ring-shaped slot to make the electromagnetic wave incident on the wave-transparent layer 1 reflect back to the wave-absorbing layer 2 more. Thus, it is better absorbed by the wave-absorbing layer 2.

[0066] Comparative Example 2-3

[0067] On the basis of Example 1, no resistance 234 is arranged on the U-shaped metal line 233, and correspondingly, 8 resistances 234 are arranged on the open metal line 213, which is a rectangle provided with an opening.

[0068] Specifically, the 8 resistances 234 are arranged on the side of the open metal line 213 where the opening is located, and the other structures remain the same as Example 1, i.e., Comparative Example 2 (i.e., structural unit 02).

[0069] Specifically, the 8 resistances 234 are arranged on the long side of the open metal line 213 close to the connecting line I 212, and the other structures remain the same as Example 1, i.e., Comparative Example 3 (i.e., structural unit 03).

[0070] The transmission / reflection characteristics of the structure of Comparative Example 2-3 are measured, and it is found that Figures 10-11 .

[0071] As can be seen from the figure, the open metal line 213 of Comparative Example 2 and Comparative Example 3 is disconnected in order to cross the resistance, and the length of the metal wire of the open metal line 213 is shortened, which can only sense the incident electromagnetic wave of a higher frequency band relative to the original wave-absorbing frequency band. Therefore, the wave-absorbing frequency band of these two structural units moves to the transmission frequency band, resulting in the disappearance of the transmission frequency band possessed by the structure of Example 1. That is Figures 10-11 , the S parameter at the frequency point marked in does not meet the requirement of the wave-transparent band.

[0072] Comparative Example 4

[0073] The 4 varactor diodes 214 on the wave-absorbing metal foil layer I 21 are removed, and the two ends crossed by the 4 varactor diodes 214 are connected together with a metal foil, and the other structures remain the same as Example 1.

[0074] The transmission / reflection characteristics of the structure of Comparative Example 4 are measured, and it is found that Figure 12 .

[0075] Comparative Example 4 contains only the varactor diode 214 on the wave-absorbing metal foil layer II 23. When the capacitance value of the varactor diode 214 is regulated, the regulation range is 0.2 pF to 1 pF. The wave-absorbing characteristics of the structure can be seen. In the frequency band around 10 GHz, when the capacitance value is changed, the frequency band does not change, only the degree of wave-absorption is changed. Figure 12 The wave-absorbing characteristics of the structure can be seen. In the frequency band around 10 GHz, when the capacitance value is changed, the frequency band does not change, only the degree of wave-absorption is changed.

[0076] It should be understood by those of ordinary skill in the art that the above discussion of any of the embodiments is merely exemplary and is not intended to suggest any limitation as to the scope of use or functionality of the application; nor do the embodiments minimize the applicability or functionality as set forth in the claims. It should also be understood that the steps of the exemplary methods, techniques, and processes can be carried out in any order, unless otherwise specifically limited, and that certain steps can be modified, omitted, or expanded, and certain features can be substituted, except where expressly stated otherwise. Consequently, as will be appreciated by those of skill in the art, the application is capable of numerous modifications and variations without departing from the scope of the present application.

[0077] One or more embodiments of the present application are intended to cover all such modifications and variations as fall within the scope of the application. Thus, it should be understood by those of ordinary skill in the art that any of the changes, modifications, equivalents, improvements, etc., made to any of the embodiments of the present application are intended to be included within the scope of the present application.

Claims

1. A frequency-agile absorptive and transmissive electromagnetic metasurface, characterized in that, The base unit comprises two oppositely arranged wave-transparent layer (1) and wave-absorbing layer (2). The wave-transparent layer (1) comprises wave-transparent medium substrate (12) and wave-transparent metal foil layer I (11) and wave-transparent metal foil layer II (13) arranged on both sides of the wave-transparent medium substrate (12). The wave-transparent metal foil layer I (11) is a plurality of metal spiral lines (111), and the wave-transparent metal foil layer II (13) comprises a metal foil (131) provided with an annular gap (132) and a rectangular gap (133) distributed around the annular gap (132). The wave-absorbing layer (2) comprises wave-absorbing medium substrate (22) and wave-absorbing metal foil layer I (21) and wave-absorbing metal foil layer II (23) arranged on both sides of the wave-absorbing medium substrate (22). The wave-absorbing metal foil layer I (21) comprises a closed loop metal wire I (211) provided with a plurality of resonant structures I, the resonant structure I comprises a connecting line I (212) connected to the closed loop metal wire I (211) and an open metal wire (213) connected to the connecting line I (212); the connecting line I (212) and / or the open metal wire (213) are provided with a varactor (214); The wave-absorbing metal foil layer II (23) comprises a closed loop metal wire II (231) provided with a plurality of resonant structures II, the resonant structure II comprises a connecting line II (232) connected to the closed loop metal wire II (231) and a U-shaped metal wire (233) connected to the connecting line II (232); the connecting line II (232) is provided with a varactor (214), and the U-shaped metal wire (233) is provided with a resistor (234).

2. The metasurface of claim 1, wherein, The wave-transparent layer (1) and the wave-absorbing layer (2) are air.

3. The metasurface of claim 1, wherein, The wave-transparent layer (1) and the wave-absorbing layer (2) are rectangular, and the closed loop metal wire I (211) and the closed loop metal wire II (231) are rectangular.

4. The metasurface according to any one of claims 1 to 3, wherein, The number of the metal spiral lines (111) is 4, which are arrayed on the surface of the wave-transparent medium substrate (12), and the metal spiral lines (111) are rectangular path spiral structures.

5. The metasurface of any one of claims 1-3, wherein, The shape of the annular gap (132) is rectangular.

6. The metasurface of any one of claims 1-3, wherein, The closed loop metal wire I (211) and the closed loop metal wire II (231) are rectangular, the number of the resonant structure I is 4, which are respectively located on the four edges of the closed loop metal wire I (211), and the number of the resonant structure II is 4, which are respectively located on the four edges of the closed loop metal wire II (231).

7. The metasurface of claim 6, wherein, The open metal wire (213) is a rectangle with an opening (2132), and the opening (2132) is close to the center of the closed loop metal wire I (211).

8. The metasurface of claim 6, wherein, The connecting line I (212) is provided with a varactor (214).

9. The metasurface of any one of claims 1-3, wherein, The wave-absorbing medium substrate (22) is provided with a connecting through hole (2131) connecting and conducting the open metal wire (213) and the U-shaped metal wire (233).

10. A radome, characterized by The frequency agile absorptive and transmissive metasurface comprises the frequency agile absorptive and transmissive metasurface according to any one of claims 1-9. The frequency agile absorptive and transmissive metasurface comprises the frequency agile absorptive and transmissive metasurface according to any

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