Wide-frequency-band on-off-adjustable low-scattering metamaterial antenna housing
By designing a wide-band on-off adjustable metamaterial radome with a multi-layer stacked structure and using switch control elements to achieve penetration or cutoff of electromagnetic waves, the problems of passive frequency selective surfaces being unable to change frequency response and active metamaterials having poor wave transmittance are solved, thus realizing the application of low-scattering and high-transmittance radomes.
Patent Information
- Application Number
- CN202511065146.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2025-09-30
AI Technical Summary
Existing passive frequency selective surfaces cannot change the frequency response, resulting in strong scattering of incoming waves within the antenna cover, limiting the stealth function. In addition, existing active metamaterials have problems such as poor wave transmittance and large period in the on-off structure design in the low-frequency band.
A low-scattering metamaterial radome with wide-band on-off adjustable function is designed. It adopts a multi-layer stacked structure, including first to fourth frequency selective surface layers and a substrate layer. By setting a switch control element in the first frequency selective surface layer, the penetration or cutoff control of electromagnetic waves in different states can be achieved.
It realizes L-band broadband wave transmission/cutoff on-off control, reduces the radar scattering cross section within and outside the antenna band, has high wave transmittance and isolation, and is suitable for radar covers and electronic warfare antenna covers with both stealth and radiation functions.
Smart Images
Figure CN120728232A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of metamaterials, and in particular to a low-scattering metamaterial antenna cover with wide-band on / off adjustment. Background Art
[0002] Traditional passive frequency selective surfaces (FSSs) have limitations because their frequency response cannot be altered once fabricated. For example, while they effectively achieve out-of-band stealth, in-band waves can enter the radome, causing strong scattering at the antenna and limiting its stealth capabilities. Active FSSs offer a solution to this problem, enabling metamaterials to switch between frequency conversion, frequency stabilization, and wave transmission and reflection, providing a method for achieving in-band stealth for radomes and a promising path to intelligent aircraft.
[0003] In addition to adjustable resonance, active metamaterials can also enable microstructure miniaturization. By modifying the capacitance and inductance between or within microstructures, the resonant frequency of traditional passive devices can be lowered, achieving miniaturization. This is crucial for stabilizing the incident angle, reducing grating lobes, and mitigating edge scattering in metamaterials. F. Bayatpur et al. designed a new miniaturized, controllable metamaterial with X-band resonance. The unit cell size is 1 / 12 of the wavelength, six times smaller than that of traditional microstructure units. They then connected two strip-shaped microstructures using vias to create a 2.5D bandpass active metamaterial switch in air. This structure switches on and off at a resonant frequency of 8 GHz, with a unit cell period of only 4.8 mm. The upper and lower metal strips in this structure serve as both part of the microstructure and as feed lines for the diode, effectively reducing structural complexity and preventing the impact of the feed network on the electrical performance. However, due to the higher resonant frequency of these structures, switching on and off in the S-band requires a longer period or a higher applied voltage. A. Ebrahimi et al. designed a multi-layer active frequency selective surface (AFSS) with a passband that can be shifted between 4 and 5 GHz, but with poor wave transmission. SCBakshi et al. designed a two-layer AFS loaded with diodes and resistors, achieving S-band wave transmission and cutoff state switching. This achieved high isolation, but with poor wave transmission and a large period. Therefore, there is considerable design potential for structures that are adjustable and switchable at low frequencies, compact, have high isolation, and good wave transmission. Summary of the Invention
[0004] An embodiment of the present invention proposes a low-scattering antenna cover with adjustable on / off in a wide frequency band, which solves the technical problem of how to enable the antenna cover to achieve a low-frequency and wide-band passband when at least one switch control element is in the "on" state, and to achieve strong cutoff and high wave transmittance within the passband when at least one switch control element is in the "off" state.
[0005] An embodiment of the present invention provides a low-scattering metamaterial radome with adjustable on / off function over a wide frequency band, characterized in that the radome is laminated in the following order from the outside to the inside: a first frequency selective surface layer, a first base layer, a second frequency selective surface layer, a core material layer, a third frequency selective surface layer, a second base layer, and a fourth frequency selective surface layer;
[0006] The first frequency selective surface layer, the second frequency selective surface layer, the third frequency selective surface layer and the fourth frequency selective surface layer all include a substrate and a conductive microstructure arranged on the substrate, and at least one switch control element is arranged in the conductive microstructure of the first frequency selective surface layer; when the at least one switch control element is turned on, electromagnetic waves in a predetermined low frequency band in a preset frequency band penetrate the antenna cover; when the at least one switch control element is turned off, the antenna cover cuts off the electromagnetic waves in the preset frequency band.
[0007] The beneficial effects of the present invention are:
[0008] The wide-band, on-off adjustable, low-scattering metamaterial radome described in the present invention can achieve L-band broadband wave transmission / cutoff control. By rationally designing the active and passive layers, a low-frequency, wide-band passband (i.e., a 0.89-1.38 GHz wide-band passband) can be achieved when the switching diode is in the "on" state (i.e., the conducting state); strong cutoff is achieved in the 0-18 GHz frequency band when the switching diode is in the "off" state, reducing the radar cross section within and outside the antenna band. This design can be applied to radomes and electronic warfare radomes that combine stealth and radiation functions. Furthermore, the isolation between the wave transmission / reflection states is high, and the wave transmittance within the passband is high. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0010] Figure 1 3 is a schematic structural diagram of a low-scattering metamaterial antenna cover with adjustable on / off function over a wide frequency band according to an embodiment of the present invention.
[0011] Figure 2 yes Figure 1 Schematic diagram of the specific structure of the first frequency selective surface layer and the second frequency selective surface layer.
[0012] Figure 3 yes Figure 1 Schematic diagram of the specific structure of the third frequency selective surface layer and the fourth frequency selective surface layer.
[0013] Figure 4 yes Figure 1 The wave transmission curves of the antenna cover shown in the figure are when the switching diode is in the on (on) and off (off) states. DETAILED DESCRIPTION
[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.
[0015] Figure 1 A wide-band on-off adjustable low-scattering metamaterial radome 100 according to an embodiment of the present invention is shown. The stacking sequence of the radome 100 from the outside to the inside is a first frequency selective surface layer 10, a first base layer 20, a second frequency selective surface layer 30, a core material layer 40, a third frequency selective surface layer 50, a second base layer 60 and a fourth frequency selective surface layer 80.
[0016] The first frequency selective surface layer 10, the second frequency selective surface layer 30, the third frequency selective surface layer 50 and the fourth frequency selective surface layer 80 all include a substrate and a conductive microstructure arranged on the substrate. At least one switching diode is arranged in the conductive microstructure of the first frequency selective surface layer 10; when the at least one switching diode is turned on, electromagnetic waves in a predetermined low frequency band in a preset frequency band penetrate the antenna cover 100; when the at least one switching diode is turned off, the antenna cover 100 cuts off the electromagnetic waves in the preset frequency band.
[0017] In this embodiment of the present invention, the first base layer 20 and the second base layer 60 are both made of FR4 (i.e., glass fiber reinforced epoxy resin). The substrates of the first frequency selective surface layer 10, the second frequency selective surface layer 30, the third frequency selective surface layer 50, and the fourth frequency selective surface layer 80 are all PI films (i.e., polyimide films). The core layer 40 is a foam layer or a honeycomb layer; preferably, the core layer 40 is a PMI foam layer.
[0018] In this embodiment of the present invention, the dielectric constants of the substrates of the first, second, third, and fourth frequency selective surface layers 10, 30, 50, and 80 are all 3.5 and 0.002, respectively. The dielectric constants of the first and second base layers 20, 60 are both 4.3 and 0.025, respectively. The dielectric constant of the core layer 40 is 1.11 and the loss tangent is 0.005.
[0019] In the embodiment of the present invention, the thickness of the first frequency selective surface layer 10, the second frequency selective surface layer 30, the third frequency selective surface layer 50 and the fourth frequency selective surface layer 80 are all 0.025 mm, the thickness of the first base layer 20 and the second base layer 60 are both 1 mm, and the thickness of the core material layer 40 is 10 mm.
[0020] like Figure 2 As shown, in one embodiment of the present invention, the at least one switching control element is six switching diodes 16, and the conductive microstructure of the first frequency selective surface layer 10 includes a mutually orthogonal first I-shape 12 and a second I-shape 14, six switching diodes 16, and six first feeding holes 18, and the six switching diodes 16 correspond to the six first feeding holes 18 one by one; the middles of the two mutually parallel sides in the first I-shape 12 are connected to the corresponding first feeding holes 18 in sequence through the switching diodes 16 and the feeding lines; the two ends of the two mutually parallel sides in the second I-shape 14 are connected to the corresponding first feeding holes 18 in sequence through the switching diodes 16 and the feeding lines.
[0021] See also Figure 2 The conductive microstructure of the second frequency selective surface layer 30 includes six identical first conductive geometric structures 32, a second conductive geometric structure 34 and six second feeding holes 38. The six first conductive geometric structures 32 are connected end to end in sequence to form an approximately regular hexagonal structure, and a first gap is formed at the center position of the approximately regular hexagonal structure and a second gap is formed between any two adjacent first conductive geometric structures 32; the six second feeding holes 38 are respectively arranged at the six end points of the approximately regular hexagonal structure.
[0022] Each first conductive geometric structure 32 includes a plurality of raised curve segments, the shapes of the plurality of raised curve segments are the same as the shape of the rectangular wave of the positive half cycle, the plurality of raised curve segments are arranged in a row in the horizontal direction, and the gaps formed between any two adjacent raised curve segments are the same; the heights of the plurality of raised curve segments arranged in a row in the vertical direction first increase and then decrease; the raised curve segment at the head end of the plurality of raised curve segments arranged in a row is connected to a second feeding through-hole 38 through a feed line, and the raised curve segment at the end of the plurality of raised curve segments arranged in a row is connected to another second feeding through-hole 38 through the gap and the feed line in sequence.
[0023] The second conductive geometric structure 34 includes a regular hexagonal single-ring structure and six first straight line segments. The regular hexagonal single-ring structure is arranged in the first gap, and the six first straight line segments are respectively arranged in the six second gaps. One end of the six first straight line segments is respectively connected to the six end points of the single-ring structure, and the other ends of the six first straight line segments respectively extend into the corresponding second gaps.
[0024] Specifically, in the first frequency selective surface layer 10 , the line width W1 of the first I-shape and the second I-shape are both 0.1 mm.
[0025] In the second frequency selective surface layer 30, the high-level continuous line segment length g1 of the multiple convex curve segments is 0.15 mm, and the line width w2 of the multiple convex curve segments is 0.04 mm; the side length r1 of the single ring structure of the regular hexagon is 0.5 mm; the line width w3 of the single ring structure of the regular hexagon and the six straight line segments is 0.2 mm.
[0026] like Figure 3 As shown, the conductive microstructure of the third frequency selective surface layer 50 is a regular hexagonal single ring structure.
[0027] See also Figure 3 The conductive microstructure of the fourth frequency selective surface layer 80 includes six identical third conductive geometric structures 82 and six identical fourth conductive geometric structures 84. The six third conductive geometric structures 82 are sequentially connected end to end to form a substantially annular structure, and a third gap is formed at the center of the substantially annular structure. The six fourth conductive geometric structures 84 are all disposed within the third gap and are sequentially arranged end to end adjacent to each other to form a substantially regular hexagonal structure.
[0028] Each third conductive geometric structure 82 includes a rectangular wave-shaped bending portion and two bending lines, wherein the two bending lines are respectively connected to two ends of the bending portion;
[0029] Each fourth conductive geometric structure 84 includes a triangular open ring structure and two second straight line segments, the two second straight line segments are respectively connected to the two ends of the opening of the triangular open ring structure, and the two second straight line segments of each fourth conductive geometric structure 84 are respectively connected to the bending lines of the corresponding two adjacent third conductive geometric structures 82 at one end away from the opening.
[0030] Specifically, in the third frequency selective surface layer 50 , the side length r2 and line width w4 of the regular hexagonal single ring structure are 2.45 mm and 0.17 mm, respectively.
[0031] In the fourth frequency selective surface layer 80 , the line width w5 of each third conductive geometric structure 82 and each fourth conductive geometric structure 84 is 0.05 mm, and the high-level continuous line segment length and low-level continuous line segment length g2 of the rectangular wave bend are both 0.08 mm.
[0032] In this way, the following technical effects can be achieved: when all six switching diodes 16 are turned on, electromagnetic waves in a predetermined low frequency band in the preset frequency band penetrate the antenna cover 100; when all six switching diodes 16 are turned off, the antenna cover 100 cuts off the electromagnetic waves in the preset frequency band.
[0033] The preset frequency range is 0 to 18 GHz, and the predetermined low frequency range in the preset frequency range is 0.89 to 1.38 GHz; that is, please refer to Figure 4 The schematic diagram of the wave transmission curve simulation of the radome 100 is shown. When all six switching diodes 16 are turned on, electromagnetic waves in the frequency range of 0.89 to 1.38 GHz penetrate the radome 100 (specifically, the wave transmission rate of the radome 100 to electromagnetic waves in the frequency range of 0.89 to 1.38 GHz is greater than or equal to 73%, that is, high wave transmission is achieved; as shown in FIG. Figure 4 When all six switching diodes 16 are turned off (i.e., off), the antenna cover 100 cuts off the electromagnetic waves in the frequency range of 0 to 18 GHz, and the wave transmittance in the cut-off section is less than 10%. Figure 4 shown.
[0034] Optionally, in another embodiment of the present invention, the at least one switching control element is four switching diodes, and the conductive microstructure of the second frequency selective surface layer includes four identical first conductive geometric structures, a second conductive geometric structure, and four second feeding through-holes, wherein the four first conductive geometric structures are sequentially connected end to end to form an approximately regular quadrilateral structure, and a first gap is formed at the center of the approximately regular quadrilateral structure, and a second gap is formed between any two adjacent first conductive geometric structures; the four second feeding through-holes are respectively arranged at the four endpoints of the approximately regular quadrilateral structure;
[0035] Each first conductive geometric structure includes a plurality of raised curve segments, each having a shape identical to a positive half-cycle of a rectangular wave, the plurality of raised curve segments being arranged in a row in the horizontal direction, and the gaps formed between any two adjacent raised curve segments being identical; the heights of the plurality of raised curve segments arranged in a row first increase and then decrease in the vertical direction; the leading end of the plurality of raised curve segments arranged in a row being connected to a second feed through-hole via a feed line, and the trailing end of the plurality of raised curve segments arranged in a row being connected to another second feed through-hole via the gaps and the feed line in sequence;
[0036] The second conductive geometric structure includes a single-ring structure of a regular quadrilateral and four first straight line segments. The single-ring structure of the regular quadrilateral is arranged in the first gap, and the four first straight line segments are respectively arranged in the four second gaps. One end of the four first straight line segments is respectively connected to the four end points of the single-ring structure, and the other ends of the four first straight line segments extend into the four second gaps respectively.
[0037] Correspondingly, the conductive microstructure of the first frequency selective surface layer 10 includes the four switching diodes, the four first feed through-holes, and a first I-shaped and a second I-shaped structure that are orthogonal to each other (i.e., the at least one switching control element is four switching diodes). The four switching diodes correspond one-to-one to the four first feed through-holes; the middle of the two mutually parallel sides of the first I-shaped structure are connected to the corresponding first feed through-holes in sequence through the switching diodes and the feed lines; and one end of the two mutually parallel sides of the second I-shaped structure are connected to the corresponding first feed through-holes in sequence through the switching diodes and the feed lines.
[0038] The conductive microstructure of the third frequency selective surface layer 50 is a single-ring structure of a regular quadrilateral.
[0039] The conductive microstructure of the fourth frequency selective surface layer 80 includes four identical third conductive geometric structures and four identical fourth conductive geometric structures. The four third conductive geometric structures are sequentially connected end to end to form a substantially annular structure, and a third gap is formed at the center of the substantially annular structure. The four fourth conductive geometric structures are all arranged in the third gap and are sequentially arranged end to end adjacent to each other to form a substantially regular quadrilateral structure.
[0040] Each third conductive geometric structure includes a rectangular wave-shaped bending portion and two bending lines, wherein the two bending lines are respectively connected to two ends of the bending portion;
[0041] Each fourth conductive geometric structure includes a triangular open ring structure and two second straight line segments, the two second straight line segments are respectively connected to the two ends of the opening of the triangular open ring structure, and the two second straight line segments of each fourth conductive geometric structure are respectively connected to the bending lines of the corresponding two adjacent third conductive geometric structures at one end away from the opening.
[0042] In this way, optionally, in another embodiment of the present invention, the following technical effects can also be achieved: when all four switching diodes are turned on, electromagnetic waves in a predetermined low frequency band in a preset frequency band penetrate the antenna cover 100; when all four switching diodes are turned off, the antenna cover 100 cuts off the electromagnetic waves in the preset frequency band.
[0043] This invention describes an active low-scattering switchable composite metamaterial radome (i.e., a low-scattering radome with wide-band on / off control), capable of achieving resonance regulation and on / off control across electromagnetic wave bands. Its small period, high isolation, thin thickness, simple structure, and ease of implementation facilitate stealth and resonance control of the radome and antenna, and its application in electronic warfare, communications, and other radome applications.
[0044] This invention describes a low-frequency, low-scattering switchable composite metamaterial radome (i.e., a low-scattering metamaterial radome with wideband on / off control), capable of L-band broadband wave transmission / cutoff control. Through the rational design of the active and passive layers, full cutoff is achieved in the 0-18 GHz frequency band when the switch diode is in the "off" position, reducing both in-band and out-of-band radar cross-sections. This design is applicable to radomes and electronic warfare radomes that combine stealth and radiation capabilities.
[0045] The present invention has a simple structure and is easy to manufacture. Miniaturization is achieved through winding and the introduction of switching diodes. Through the rational design of the microstructure and the arrangement of the switching diodes in their operating states, a low-frequency, wide-band passband is achieved in the "on" state (i.e., conducting state) of the switching diodes, while strong cutoff is achieved in the "off" state (i.e., shutoff state). High isolation is achieved in both the transmission and reflection states, and high wave transmission within the passband is achieved.
[0046] The most difficult parts of the present invention are (1) the design of the two "on" and "off" states of the switching diode to achieve a large isolation; (2) the design of a miniaturized structure in the low frequency band (L band); (3) the low frequency broadband passband with stable angle; and (4) the full frequency band cutoff in the "off" state.
[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A low-scattering metamaterial antenna cover with adjustable on / off function over a wide frequency band, characterized in that: The lamination sequence of the radome from outside to inside is the first frequency selective surface layer, the first base layer, the second frequency selective surface layer, the core material layer, the third frequency selective surface layer, the second base layer and the fourth frequency selective surface layer; The first frequency selective surface layer, the second frequency selective surface layer, the third frequency selective surface layer and the fourth frequency selective surface layer each include a substrate and a conductive microstructure disposed on the substrate, and at least one switch control element is disposed in the conductive microstructure of the first frequency selective surface layer; When the at least one switch control element is turned on, electromagnetic waves in a predetermined low frequency band in a preset frequency band penetrate the antenna cover; when the at least one switch control element is turned off, the antenna cover cuts off the electromagnetic waves in the preset frequency band.
2. The radome according to claim 1, wherein: The first base layer and the second base layer are both made of FR4 material, and the substrates of the first frequency selective surface layer, the second frequency selective surface layer, the third frequency selective surface layer and the fourth frequency selective surface layer are all PI films; the core material layer is a foam layer or a honeycomb layer; preferably, the core material layer is a PMI foam layer; The dielectric constants of the substrates of the first frequency selective surface layer, the second frequency selective surface layer, the third frequency selective surface layer and the fourth frequency selective surface layer are all 3.5, and the loss tangents are all 0.002; the dielectric constants of the first base layer and the second base layer are both 4.3, and the loss tangents are both 0.025; the dielectric constant of the core material layer is 1.11, and the loss tangent is 0.
005.
3. The radome according to claim 2, wherein: The thickness of the first frequency selective surface layer, the second frequency selective surface layer, the third frequency selective surface layer and the fourth frequency selective surface layer are all 0.025 mm, the thickness of the first base layer and the second base layer are both 1 mm, and the thickness of the core material layer is 10 mm.
4. The radome according to claim 1, wherein: The at least one switching control element is six switching diodes, and the conductive microstructure of the first frequency selective surface layer includes six first feed holes and mutually orthogonal first I-shapes and second I-shapes. The six switching diodes correspond to the six first feed holes one by one; the middles of the two mutually parallel sides of the first I-shape are connected to the corresponding first feed holes in sequence through switching diodes and feed lines; the two ends of the two mutually parallel sides of the second I-shape are connected to the corresponding first feed holes in sequence through switching diodes and feed lines.
5. The radome according to claim 4, wherein: The conductive microstructure of the second frequency selective surface layer includes six identical first conductive geometric structures, a second conductive geometric structure, and six second feed through holes, wherein the six first conductive geometric structures are sequentially connected end to end to form an approximately regular hexagonal structure, and a first gap is formed at the center of the approximately regular hexagonal structure, and a second gap is formed between any two adjacent first conductive geometric structures; the six second feed through holes are respectively arranged at the six endpoints of the approximately regular hexagonal structure; Each first conductive geometric structure includes a plurality of raised curve segments, each having a shape identical to a positive half-cycle of a rectangular wave, the plurality of raised curve segments being arranged in a row in the horizontal direction, and the gaps formed between any two adjacent raised curve segments being identical; the heights of the plurality of raised curve segments arranged in a row first increase and then decrease in the vertical direction; the leading end of the plurality of raised curve segments arranged in a row being connected to a second feed through-hole via a feed line, and the trailing end of the plurality of raised curve segments arranged in a row being connected to another second feed through-hole via the gaps and the feed line in sequence; The second conductive geometric structure includes a regular hexagonal single-ring structure and six first straight line segments. The regular hexagonal single-ring structure is arranged in the first gap, and the six first straight line segments are respectively arranged in the six second gaps. One end of the six first straight line segments is respectively connected to the six end points of the single-ring structure, and the other ends of the six first straight line segments respectively extend into the six second gaps; each first feeding through hole and each corresponding second feeding through hole are respectively connected to the positive and negative poles of the power supply through a feeder line to power the corresponding switching diode.
6. The radome according to claim 5, wherein: The line width W1 of the first I-shape and the second I-shape are both 0.1 mm; The high-level continuous line segment length g1 of the multiple convex curve segments is 0.15mm, and the line width w2 of the multiple convex curve segments is 0.04mm; the side length r1 of the single ring structure of the regular hexagon is 0.5mm; the line width w3 of the single ring structure of the regular hexagon and the six straight line segments is 0.2mm.
7. The radome according to claim 5, wherein: The conductive microstructure of the third frequency selective surface layer is a single ring structure of a regular hexagon or a regular quadrilateral.
8. The radome according to claim 7, wherein: The conductive microstructure of the fourth frequency selective surface layer includes six identical third conductive geometric structures and six identical fourth conductive geometric structures, wherein the six third conductive geometric structures are sequentially connected end to end to form an approximately ring-shaped structure, and a third gap is formed at the center of the approximately ring-shaped structure; the six fourth conductive geometric structures are all arranged in the third gap and are sequentially arranged end to end adjacent to each other to form an approximately regular hexagonal structure. Each third conductive geometric structure includes a rectangular wave-shaped bending portion and two bending lines, wherein the two bending lines are respectively connected to two ends of the bending portion; Each fourth conductive geometric structure includes a triangular open ring structure and two second straight line segments, the two second straight line segments are respectively connected to the two ends of the opening of the triangular open ring structure, and the two second straight line segments of each fourth conductive geometric structure are respectively connected to the bending lines of the corresponding two adjacent third conductive geometric structures at one end away from the opening.
9. The radome according to claim 8, wherein: The side length r2 and line width w4 of the regular hexagonal single ring structure are 2.45 mm and 0.17 mm respectively; The line width w5 of each third conductive geometric structure and each fourth conductive geometric structure is 0.05 mm, and the high-level continuous line segment length and the low-level continuous line segment length g2 of the rectangular wave bending portion are both 0.08 mm.
10. The radome according to claim 9, wherein: The preset frequency band is 0-18 GHz, and the predetermined low frequency band in the preset frequency band is 0.89-1.38 GHz.