Broadband bandwidth angle RCS reduction metasurface fusing OAM characteristics

Abstract

The invention discloses a broadband bandwidth angle RCS reduction metasurface fused with OAM characteristics, which is formed by periodically arranging a plurality of metasurface units, and each metasurface unit sequentially comprises a first dielectric substrate, a metal patch, a second dielectric substrate and a metal grounding plane from the top layer to the bottom layer; the metal patch comprises a first arc metal patch and a second arc metal patch; the first arc-shaped metal patch and the second arc-shaped metal patch are the same in structural size, are arranged concentrically and are of a central symmetry structure about the circle center; through rotation of the metasurface unit, 0-360-degree continuous reflection phase coverage is realized based on a PB phase principle. Through fusion of OAM vortex phase characteristics, a composite phase formula is adopted to superpose a vortex phase and an RCS phase, and protruding beams in a scattered field are counteracted. Reflected electromagnetic waves are controlled by controlling rotation of the metasurface units, so that broadband and wide-angle efficient RCS reduction is achieved, protruding beams are counteracted, and the problem of scattering energy concentration is solved.

Description

Technical Field

[0001] This invention relates to the field of artificial electromagnetic metamaterials technology, and in particular to a broadband angle RCS-reduced metasurface that incorporates OAM properties. Background Technology

[0002] Metamaterials are artificial structures designed based on the equivalent medium theory. Among them, metasurfaces, as its two-dimensional counterpart, have attracted much attention due to their low profile, easy integration, and small space occupation. They can also flexibly control the amplitude, phase, and polarization state of electromagnetic waves and have been extensively studied in the field of radar cross section (RCS) reduction in recent years.

[0003] A typical method for traditional RCS reduction is to arrange polarization conversion metasurfaces (PCMs) in a checkerboard array, using a 180° phase difference between adjacent cells to achieve destructive interference of the scattered field. However, this method redistributes the scattered energy and forms four significant directional beams, limiting the RCS reduction effect. While coded metasurfaces, developed subsequently, can control the scattering pattern by designing coded sequences, their performance heavily relies on optimization algorithms, often requiring significant computational resources and time, resulting in low design efficiency and limited engineering practicality.

[0004] Therefore, the existing technology still has the following prominent problems:

[0005] First, the scattered energy is concentrated in a specific direction, resulting in a limited RCS reduction bandwidth and angle range;

[0006] Second, the design of coded metasurfaces is highly dependent on numerical optimization, which is computationally expensive and time-consuming.

[0007] Third, while existing methods achieve high-efficiency RCS reduction over wide bandwidth and wide angle, they struggle to balance low design complexity with low-energy focusing characteristics.

[0008] To advance this technology, it is necessary to explore novel metasurface architectures and design strategies that can improve RCS reduction performance while reducing design complexity and computational overhead, and effectively suppress the spatial concentration of scattered energy. Summary of the Invention

[0009] The purpose of this invention is to provide a composite phase-tunable metasurface based on PB (Pancharatnam-Berry) phase and OAM vortex characteristics that is simple in structure and easy to implement. It can achieve wide-bandwidth and wide-angle efficient RCS reduction, while canceling out-of-focus beams and solving the problem of concentrated scattered energy.

[0010] The technical solution to achieve the purpose of this invention is: a wideband bandwidth angle RCS-reduced metasurface that integrates OAM characteristics, characterized in that the RCS-reduced metasurface is composed of multiple metasurface units arranged periodically, with the lower left corner of each metasurface unit being the origin O, the rightward direction being the positive X-axis, and the vertical upward direction being the positive Y-axis;

[0011] Each metasurface unit consists of a first dielectric substrate, a metal patch, a second dielectric substrate, and a metal ground plane, arranged sequentially from top to bottom. The metal patch includes a first arc-shaped metal patch and a second arc-shaped metal patch. The first arc-shaped metal patch and the second arc-shaped metal patch have the same structural dimensions, are arranged at the same center, and are centrally symmetrical about the center.

[0012] By rotating the metasurface unit, continuous reflection phase coverage from 0° to 360° is achieved based on the PB phase principle; by integrating the OAM vortex phase characteristics, the vortex phase and RCS phase are superimposed using a composite phase formula to cancel out the prominent beams in the scattered field.

[0013] Furthermore, by changing the rotation direction of the metal patch, the phase and amplitude of the reflected electromagnetic wave are controlled, so that the phase and amplitude of the reflected electromagnetic wave are mapped to the rotation direction of the metal patch.

[0014] Furthermore, the unit phase design of the metal patch must satisfy the following formula:

[0015]

[0016] In the formula, It is the phase of the metasurface unit. This refers to the position coordinates of the metasurface unit. It is the topological charge number.

[0017] Furthermore, the vortex phase and the RCS phase are superimposed using a composite phase formula, which is as follows:

[0018]

[0019] In the formula, It is a wideband bandwidth angle RCS-reduced metasurface that incorporates OAM characteristics for phase reduction. This refers to RCS reducing the metasurface phase. It is a vortex phase.

[0020] Furthermore, based on the composite phase formula, the compensation phase of the incident wave arriving at each metasurface unit is calculated, and the RCS-reduced metasurface is optimized.

[0021] Furthermore, the first dielectric substrate has a square structure with a side length of 8 mm, is made of polytetrafluoroethylene, has a thickness of 1.8 mm, has a dielectric constant of 2.2, and a loss tangent of 0.0007.

[0022] Furthermore, the second dielectric substrate has a square structure with a side length of 8 mm, is made of polytetrafluoroethylene, has a thickness of 3.2 mm, has a dielectric constant of 2.2, and a loss tangent of 0.0007.

[0023] Furthermore, the metal grounding plane has a square structure with a side length of 8mm and a thickness of 0.035mm, enabling total internal reflection.

[0024] Furthermore, the structural period of the metasurface unit is 8 mm.

[0025] Furthermore, the RCS-reduced metasurface is provided with 32×32 metasurface units.

[0026] Compared with the prior art, the significant advantages of this invention are:

[0027] (1) Design a double circular arc metasurface unit. By rotating the unit with the PB phase, continuous reflection phase coverage from 0° to 360° can be achieved, which is convenient and efficient to control.

[0028] (2) Introducing OAM vortex phase, utilizing its characteristics of zero central energy and beam divergence, effectively cancels out-of-focus beams through composite phase formula, solving the problem of concentrated scattered energy in traditional technology;

[0029] (3) By adopting a formulaic design method, only the unit position parameters need to be adjusted, without relying on wavelength information. The frequency band can be flexibly extended and extended, and the frequency band can be promoted across frequency bands, which greatly reduces the computer resources and time costs of the design.

[0030] (4) It has excellent wide bandwidth and wide angle performance, achieving RCS reduction of more than 10dB in the 6.8-21.6GHz band (relative bandwidth 104%), and can still maintain the same reduction effect when the incident angle is ≤60°, with outstanding stability. Attached Figure Description

[0031] Figure 1a This is a side view of the structure of the widebandwidth angle RCS-reduced metasurface that integrates OAM characteristics according to the present invention.

[0032] Figure 1b This is a front view of the structure of the widebandwidth angle RCS-reduced metasurface that integrates OAM characteristics according to the present invention.

[0033] Figure 2aThis is a simulation result curve of the reflection phase of the metal patch of the wideband bandwidth angle RCS reduction metasurface unit with OAM characteristics as a function of frequency.

[0034] Figure 2b This is a simulation result curve of the reflection coefficient of the metal patch of the wideband bandwidth angle RCS reduction metasurface unit with OAM characteristics as a function of frequency.

[0035] Figure 3 This invention presents three-dimensional far-field scattering diagrams of vortex metasurfaces at different representative frequencies under LCP plane wave vertical incidence conditions.

[0036] Figure 4 This invention presents three-dimensional and two-dimensional far-field scattering diagrams of the RCS metasurface at different representative frequencies under the condition of perpendicular incidence of LCP plane waves.

[0037] Figure 5 This is a schematic diagram of the deflection angle of the beam protruding from the RCS metasurface when phi=90 under the condition of perpendicular incidence of LCP plane wave.

[0038] Figure 6a This invention presents three-dimensional and two-dimensional far-field scattering diagrams of RCS-optimized metasurfaces at different representative frequencies under LCP plane wave vertical incidence conditions.

[0039] Figure 6b This is a comparison diagram of the RCS as a function of frequency when different metasurfaces are irradiated under the condition of perpendicular incidence of LCP plane waves according to the present invention.

[0040] Figure 6c This is a comparison chart of the RCS versus frequency under the condition of perpendicular incidence of LCP plane waves, when the incident angle is 0.3° or 0.6°. Detailed Implementation

[0041] This invention provides a wideband bandwidth angle RCS-reduced metasurface that integrates OAM characteristics. The RCS-reduced metasurface is characterized by being composed of multiple metasurface units arranged periodically, with the lower left corner of each metasurface unit being the origin O, the rightward direction being the positive X-axis, and the vertical upward direction being the positive Y-axis.

[0042] Each metasurface unit consists of a first dielectric substrate 1, a metal patch 2, a second dielectric substrate 3, and a metal ground plane 4, from top to bottom. The metal patch 2 includes a first arc-shaped metal patch 21 and a second arc-shaped metal patch 22. The first arc-shaped metal patch 21 and the second arc-shaped metal patch 22 have the same structural dimensions, are arranged at the same center, and are centrally symmetrical about the center.

[0043] By rotating the metasurface unit, continuous reflection phase coverage from 0° to 360° is achieved based on the PB phase principle; by integrating the OAM vortex phase characteristics, the vortex phase and RCS phase are superimposed using a composite phase formula to cancel out the prominent beams in the scattered field.

[0044] As a specific example, by changing the rotation direction of the metal patch 2, the phase and amplitude of the reflected electromagnetic wave of the incident circularly polarized electromagnetic wave are controlled, so that the phase and amplitude of the reflected electromagnetic wave are mapped with the rotation direction of the metal patch 2.

[0045] As a specific example, the unit phase design requirement of the metal patch 2 is to satisfy the following formula:

[0046]

[0047] In the formula, It is the phase of the metasurface unit. This refers to the position coordinates of the metasurface unit. It is the topological charge number.

[0048] As a specific example, the composite phase formula is used to superimpose the vortex phase and the RCS phase. The composite phase formula is as follows:

[0049]

[0050] In the formula, It is a wideband bandwidth angle RCS-reduced metasurface that incorporates OAM characteristics for phase reduction. This refers to RCS reducing the metasurface phase. It is a vortex phase.

[0051] As a specific example, the compensation phase of the incident wave arriving at each metasurface unit is calculated based on the composite phase formula, thereby optimizing the RCS-reduced metasurface.

[0052] As a specific example, the first dielectric substrate 1 has a square structure with a side length of 8 mm, is made of polytetrafluoroethylene, has a thickness of 1.8 mm, has a dielectric constant of 2.2, and a loss tangent of 0.0007.

[0053] As a specific example, the second dielectric substrate 3 has a square structure with a side length of 8 mm, is made of polytetrafluoroethylene, has a thickness of 3.2 mm, a dielectric constant of 2.2, and a loss tangent of 0.0007.

[0054] As a specific example, the metal grounding plane 4 is a square structure with a side length of 8mm and a thickness of 0.035mm, which can achieve total internal reflection.

[0055] As a specific example, the structural period of the metasurface unit is 8 mm.

[0056] As a specific example, the RCS-reduced metasurface is configured with 32×32 metasurface units.

[0057] In one specific embodiment, a broadband, wide-angle RCS-reducing metasurface integrating OAM characteristics is provided. Metal patches containing 32×32 metasurface units are arranged according to the tilt direction of the metal patches. This easily implements a composite phase-tunable metasurface based on PB phase and OAM vortex characteristics, achieving broadband, wide-angle, and efficient RCS reduction while simultaneously canceling prominent beams and solving the problem of concentrated scattered energy.

[0058] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0059] Example

[0060] This embodiment provides a wideband bandwidth and wide-angle RCS reduction metasurface that integrates OAM characteristics. By controlling the rotation of the metasurface unit, the reflected electromagnetic waves can be controlled, achieving wideband and wide-angle efficient RCS reduction, while canceling outstanding beams and solving the problem of concentrated scattered energy.

[0061] Referring to Figure 1, the multifunctional coded metasurface is composed of multiple metasurface units arranged in a periodic manner. Each metasurface unit consists of a first dielectric substrate 1, a metal patch 2, a second dielectric substrate 3, and a metal ground 4, from top to bottom.

[0062] The metal patch 2 is composed of a first arc-shaped metal patch 21 and a second arc-shaped metal patch 22; the first arc-shaped metal patch 21 and the second arc-shaped metal patch 22 have the same structural dimensions, and the metal patch 2 is a centrally symmetrical shape.

[0063] Furthermore, the first arc-shaped metal sheet 21 and the second arc-shaped metal sheet 22 have the same width.

[0064] Furthermore, the metasurface first dielectric substrate 1 has a square structure with a side length of 8 mm, is made of polytetrafluoroethylene, has a thickness of 1.8 mm, and has a dielectric constant of 2.2 and a loss tangent of 0.0007.

[0065] Furthermore, the metasurface second dielectric substrate 3 has a square structure with a side length of 8 mm, is made of polytetrafluoroethylene, has a thickness of 3.2 mm, and has a dielectric constant of 2.2 and a loss tangent of 0.0007.

[0066] Furthermore, the structural period of the metasurface unit is 8 mm.

[0067] Furthermore, the unit phase design of the metal patch must satisfy the following formula:

[0068]

[0069] In the formula, It is the phase of the unit. This refers to the position coordinates of the metasurface unit. It is the topological charge number.

[0070] Furthermore, the unit phase design of the metal patch satisfies the following equation:

[0071]

[0072] In the formula, It is the phase of the RCS-reduced metasurface that incorporates OAM properties. This refers to RCS reducing the metasurface phase. It is a vortex phase.

[0073] Furthermore, the metasurface is composed of multiple metasurface units arranged periodically, and the metasurface is provided with 32×32 metasurface units.

[0074] Furthermore, the metal patch 2 can control the phase and amplitude of the reflected electromagnetic wave from the incident circularly polarized electromagnetic wave, so that the phase and amplitude of the reflected electromagnetic wave are mapped to the tilt direction of the metal patch.

[0075] Referring to Figure 1, in this embodiment, the broadband bandwidth angle RCS reduction metasurface with OAM characteristics is constructed with the first dielectric substrate 1 made of polytetrafluoroethylene (PTFE) with a dielectric constant of [insert dielectric constant here]. =2.2, loss tangent is 0.0007, thickness is h=1.8mm, and size is 8mm×8mm×1.8mm; the width of the first arc-shaped metal patch 21 and the second arc-shaped metal patch 22 of the metal patch 2 is 0.45mm; the material of the second dielectric substrate 3 is polytetrafluoroethylene, and the dielectric constant is =2.2, loss tangent is 0.0007, thickness is h=1.8mm, dimensions are 8mm×8mm×3.2mm; the reflection coefficient, reflection amplitude, and phase can be obtained. The changing relationship.

[0076] Figure 2a This embodiment is a wideband RCS-reduced metasurface with integrated OAM characteristics in reflection mode, and a 3-bit unit for the reflection phase of electromagnetic wave reflection.

[0077] Figure 2b This embodiment is a wideband angular RCS-reduced metasurface with integrated OAM characteristics, which is the reflection coefficient of the unit cell for electromagnetic wave reflection in the reflection mode.

[0078] Figure 3 In this embodiment, the widebandwidth angle RCS-reduced metasurface with integrated OAM characteristics forms vortices of different modes at different frequencies in reflection mode. Figure 3 In the equation (a), (b), and (c), l=1; (d), (e), and (f), l=2; and (g), (h), and (i), l=3.

[0079] Figure 4 In this embodiment, the RCS-reduced metasurface is presented in reflection mode under the condition of perpendicular incidence of LCP plane waves, and three-dimensional and two-dimensional far-field scattering images of the RCS metasurface at different representative frequencies are given. Figure 4 In the diagram, (a) shows the three-dimensional and two-dimensional far-field scattering patterns of the RCS metasurface at a frequency of 10 GHz, (b) shows the three-dimensional and two-dimensional far-field scattering patterns of the RCS metasurface at a frequency of 15 GHz, and (c) shows the three-dimensional and two-dimensional far-field scattering patterns of the RCS metasurface at a frequency of 20 GHz.

[0080] Figure 5 The RCS-reduced metasurface in this embodiment highlights the beam position in reflection mode.

[0081] Figure 6a In this embodiment, the wideband angle RCS-reduced metasurface with integrated OAM characteristics is presented in reflection mode under the condition of perpendicular incidence of LCP plane waves, giving three-dimensional and two-dimensional far-field scattering images of the RCS metasurface at different representative frequencies. Figure 6a In the diagram, (a) shows the three-dimensional and two-dimensional far-field scattering patterns of the RCS metasurface at a frequency of 10 GHz, (b) shows the three-dimensional and two-dimensional far-field scattering patterns of the RCS metasurface at a frequency of 15 GHz, and (c) shows the three-dimensional and two-dimensional far-field scattering patterns of the RCS metasurface at a frequency of 20 GHz.

[0082] Figure 6b This is a comparison of the RCS changes with frequency when different metasurfaces are irradiated in reflection mode using a broadband angle RCS reduction metasurface with OAM characteristics integrated in this embodiment.

[0083] Figure 6c This is a comparison chart showing the RCS of the wideband angular RCS reduction metasurface with integrated OAM characteristics in this embodiment as a function of frequency in reflection mode when the incident angle is 0.3° or 0.6°.

[0084] According to the formula:

[0085]

[0086] In the formula, It is a wideband bandwidth angle RCS-reduced metasurface that incorporates OAM characteristics for phase reduction. This refers to RCS reducing the metasurface phase. It is the vortex phase. Based on the above formula, the compensation phase of the incident wave arriving at each unit is calculated, and the RCS reduction metasurface is optimized. This metasurface achieves an RCS reduction of more than 10 dB (relative bandwidth of 104%) in the 6.8-21.6 GHz frequency band, and still maintains a reduction effect of more than 10 dB when the incident angle is ≤60°, with excellent angular stability.

[0087] In summary, this invention provides a broadband RCS-reducing metasurface that integrates OAM (Orbital Angular Momentum) characteristics. By rotating the double circular arcs as a whole, continuous reflection phase coverage from 0° to 360° can be achieved based on the PB phase principle. By integrating the OAM vortex phase characteristics, and utilizing the unique advantages of zero energy at the center of the vortex beam and beam divergence, the vortex phase and RCS phase are superimposed using a composite phase formula to efficiently cancel out prominent beams in the scattered field and solve the problem of concentrated scattered energy. This invention provides a new path for broadband RCS reduction and has significant theoretical and engineering application value in fields such as stealth technology and electromagnetic compatibility.

Claims

1. A broadband angle RCS-reduced metasurface incorporating OAM characteristics, characterized in that, The RCS-reducing metasurface is composed of multiple metasurface units arranged periodically. The lower left corner of each metasurface unit is the origin O, the rightward direction is the positive X-axis, and the vertical upward direction is the positive Y-axis. Each metasurface unit consists of a first dielectric substrate (1), a metal patch (2), a second dielectric substrate (3), and a metal ground plane (4) from top to bottom. The metal patch (2) includes a first arc-shaped metal patch (21) and a second arc-shaped metal patch (22). The first arc-shaped metal patch (21) and the second arc-shaped metal patch (22) have the same structural dimensions, are arranged at the same center, and are centrally symmetrical about the center. By rotating the metasurface unit, continuous reflection phase coverage from 0° to 360° is achieved based on the PB phase principle; by integrating the OAM vortex phase characteristics, the vortex phase and RCS phase are superimposed using a composite phase formula to cancel out the prominent beams in the scattered field.

2. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, By changing the rotation direction of the metal patch (2), the phase and amplitude of the reflected electromagnetic wave of the incident circularly polarized electromagnetic wave are controlled, so that the phase and amplitude of the reflected electromagnetic wave are mapped with the rotation direction of the metal patch (2).

3. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The unit phase design requirement of the metal patch (2) is to satisfy the following formula: In the formula, It is the phase of the metasurface unit. This refers to the position coordinates of the metasurface unit. It is the topological charge number.

4. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The vortex phase and the RCS phase are superimposed using a composite phase formula, which is as follows: In the formula, It is a wideband bandwidth angle RCS-reduced metasurface that incorporates OAM characteristics for phase reduction. This refers to RCS reducing the metasurface phase. It is a vortex phase.

5. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 4, characterized in that, Based on the composite phase formula, the compensation phase of the incident wave arriving at each metasurface unit is calculated, and the RCS-reduced metasurface is optimized.

6. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The first dielectric substrate (1) has a square structure with a side length of 8 mm. It is made of polytetrafluoroethylene with a thickness of 1.8 mm. The dielectric constant of the first dielectric substrate (1) is 2.2 and the loss tangent is 0.0007.

7. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The second dielectric substrate (3) has a square structure with a side length of 8 mm. It is made of polytetrafluoroethylene with a thickness of 3.2 mm. The dielectric constant of the second dielectric substrate (3) is 2.2 and the loss tangent is 0.0007.

8. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The metal grounding plane (4) is a square structure with a side length of 8mm and a thickness of 0.035mm, which can achieve total reflection.

9. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The structural period of the metasurface unit is 8 mm.

10. The broadband angle RCS-reduced metasurface with integrated OAM characteristics according to claim 1, characterized in that, The RCS-reduced metasurface has 32×32 metasurface units.

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