A non-developable curved metasurface device

Abstract

The present invention relates to the field of electromagnetic technology and specifically discloses a non-developable curved metasurface device, comprising: a spherical structure and a metasurface polarization converter formed on the spherical structure, wherein the metasurface polarization converter comprises a plurality of phase-modulated metasurface units arranged on the spherical structure according to a phase-modulation rule, wherein the phase-modulation rule comprises a relationship between the controlled phase of the phase-modulated metasurface unit and the position of the phase-modulated metasurface unit. The non-developable curved metasurface device provided by the present invention not only enables the non-developable curved metasurface device to have the effect of virtually imparting a flat ground stealth, but also improves broadband polarization conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic technology, and in particular to a non-developable curved metasurface device. Background Art

[0002] A metasurface is a two-dimensional equivalent structure of a metamaterial that can effectively control the propagation mode, polarization, wavefront amplitude, and phase of electromagnetic waves. It is easy to prepare and popularize. In recent years, research on phase control based on planar structures or developable surfaces such as cylindrical and rhombic shapes has developed rapidly. The demand for conformal cloaking of complex non-developable surfaces is even more widespread, but metasurfaces with complex non-developable surfaces have not yet been studied. The main difficulty in designing non-developable metasurfaces is that their conductive structure is non-periodic, while the entire surface is of finite size. Therefore, the assumption of infinite periodic structure commonly used in planar metasurface design no longer holds. The non-developable nature also makes it impossible to simply wrap a pre-designed conductive structure onto the surface. Summary of the Invention

[0003] The present invention provides a non-developable curved surface metasurface device, which solves the problem in the related art that non-developable curved surfaces cannot achieve stealth.

[0004] As one aspect of the present invention, a non-developable curved metasurface device is provided, which includes: a spherical structure and a metasurface polarization converter formed on the spherical structure, wherein the metasurface polarization converter includes a plurality of phase-controlled metasurface units arranged on the spherical structure according to a phase control rule, wherein the phase control rule includes the relationship between the control phase of the phase-controlled metasurface unit and the position of the phase-controlled metasurface unit.

[0005] Furthermore, the relationship between the control phase of the phase control metasurface unit and the position of the phase control metasurface unit is:

[0006]

[0007] Among them, α i represents the control phase of the i-th phase control metasurface unit, α0 represents the initial phase of the phase control metasurface unit, f0 represents the phase control frequency point, R represents the radius of the spherical structure, p represents the side length of the phase control metasurface unit, c represents the speed of light, and c = 3×10 8 m / s,x i Indicates the location of the i-th phase-controlled metasurface unit.

[0008] Furthermore, each of the phase-modulated metasurface units includes a conductive backplane layer located on the spherical structure, and an intermediate dielectric layer and a conductive structure layer located in sequence on the conductive backplane layer.

[0009] Furthermore, the conductive backplane layer is made of indium tin oxide, the intermediate dielectric layer is made of glass, and the conductive structure layer is made of silver.

[0010] Furthermore, the conductive structure layer includes a first double ring and a second double ring, and the first double ring and the second double ring are symmetrically arranged about the diagonal of the phase-control metasurface unit to form a non-closed ring, and a straight wire and a rectangular frame wire are arranged in the non-closed ring, and the two ends of the straight wire are respectively connected to the first double ring and the second double ring, and the straight wire passes through the rectangular frame wire and divides the rectangular frame wire into two new rectangular frame wires after passing through the rectangular frame wire.

[0011] Furthermore, the straight wire is arranged on the diagonal line of the phase control metasurface unit.

[0012] Furthermore, the first double ring includes a first inner ring line and a first outer ring line, the second double ring includes a second inner ring line and a second outer ring line, the first inner ring line and the second inner ring line symmetrically form a non-closed inner ring, the first outer ring line and the second outer ring line symmetrically form a non-closed outer ring, the first inner ring line and the second inner ring line are spaced a first distance apart, the first outer ring line and the second outer ring line are spaced a second distance apart, the second distance is greater than the first distance, the two ends of the straight wire are respectively connected to the first inner ring line and the second inner ring line, the first inner ring line and the second inner ring line both have a first arc angle, the first outer ring line and the second outer ring line both have a second arc angle, the first arc angle and the second arc angle are in a linear relationship, and changes in the first arc angle and the second arc angle can affect the control phase of the phase-control metasurface unit.

[0013] Furthermore, the relationship between the first arc angle and the second arc angle is:

[0014] t2=0.63*t1+11.7,

[0015] Wherein, t2 represents the second arc angle, and t1 represents the first arc angle.

[0016] Furthermore, the shape of the conductive structure layer includes a non-closed double-circular structure and / or a "Z"-shaped structure.

[0017] Furthermore, each of the phase-modulated metasurface units is mapped onto the spherical structure by vertical mapping.

[0018] In the present invention, multiple phase-controlled metasurface units are arranged on a spherical structure, and these phase-controlled metasurface units are arranged according to phase-control rules. Since these phase-controlled metasurface units can be arranged according to phase-control rules, that is, they can be arranged according to the phase for achieving stealth, not only can the non-developable curved metasurface device have the effect of virtually forming a flat ground stealth, but also the broadband polarization conversion efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention.

[0020] Figure 1 A top view of the non-developable curved metasurface device provided by the present invention.

[0021] Figure 2 A three-dimensional diagram of the non-developable curved metasurface device provided by the present invention.

[0022] Figure 3 This is a schematic diagram of the phase control principle provided by the present invention.

[0023] Figure 4 Schematic diagram of the arrangement of the metasurface phase control units provided by the present invention.

[0024] Figure 5 This is a three-dimensional diagram of the surface conductive structure provided by the present invention.

[0025] Figure 6 This is a top view of the surface conductive structure provided by the present invention.

[0026] Figure 7 A comparison diagram of the reflected electric field phase distribution of three structures provided by the present invention: a spherical surface covered with a phase-controlled metasurface, a PEC spherical surface, and a PEC plane.

[0027] Figure 8 A comparison diagram of the co-polarization and cross-polarization components of the bistatic RCS of a sphere covered with a phase-controlled metasurface provided by the present invention and the co-polarization components of the PEC sphere and PEC plane.

[0028] Figure 9 A comparison diagram of the cross-polarization component and co-polarization component of the RCS of a single station on a spherical surface covered with a phase-controlled metasurface provided by the present invention.

[0029] Figure 10 The polarization conversion rate of a spherical surface covered with a phase-modulated metasurface provided by the present invention. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0033] In this embodiment, a non-developable curved metasurface device is provided. Figure 1 is a top view of a non-developable curved metasurface device provided according to an embodiment of the present invention, Figure 2 : is a stereoscopic diagram of a non-developable curved metasurface device according to an embodiment of the present invention, as shown in FIG. Figure 1 and Figure 2 As shown, it includes: a spherical structure 100 and a metasurface polarization converter 200 formed on the spherical structure 100, wherein the metasurface polarization converter 200 includes a plurality of phase-controlled metasurface units 210 arranged on the spherical structure 100 according to a phase control rule, wherein the phase control rule includes the relationship between the control phase of the phase-controlled metasurface unit 210 and the position of the phase-controlled metasurface unit 210.

[0034] In an embodiment of the present invention, a plurality of phase-controlled metasurface units are arranged on a spherical structure, and these phase-controlled metasurface units are arranged according to phase-control rules. Since these phase-controlled metasurface units can be arranged according to the phase-control rules, that is, they can be arranged according to the phase for achieving stealth, not only can the non-developable curved metasurface device have the effect of virtually forming a flat ground stealth, but also the broadband polarization conversion efficiency can be improved.

[0035] In the embodiment of the present invention, the non-developable curved surface may specifically include a curved surface with different curvatures at different positions, that is, an irregular curved surface.

[0036] Specifically, the relationship between the control phase of the phase control metasurface unit and the position of the phase control metasurface unit is:

[0037]

[0038] Among them, α i represents the control phase of the i-th phase control metasurface unit, α0 represents the initial phase of the phase control metasurface unit, f0 represents the phase control frequency point, R represents the radius of the spherical structure, p represents the side length of the phase control metasurface unit, c represents the speed of light, and c = 3×10 8 m / s,x i Indicates the location of the i-th phase-controlled metasurface unit.

[0039] Among them, the initial phase of the phase-controlled metasurface unit can be set as needed and is not limited here.

[0040] It should be noted that the reference plane may specifically refer to a phase compensation reference plane, such as Figure 3 As shown, phase compensation is performed for a frequency of 20 GHz, with the plane where P(0) is located as the phase compensation reference plane, and different unit arrangements are made with the same cross-sectional height d, such as arranging unit 1 within the cross-sectional height 0 to d, arranging unit 2 within the cross-sectional height d to 2d, and so on. The cross-polarization reflection phase of the first unit, i.e., the initial phase α0, is taken as -177.6°, and the geometric parameters of the unit structure (the arc angles t1 and t2 of the conductive structure of the phase-controlled metasurface unit) are adjusted. Five different unit structures are selected for simulation optimization. The structural parameters are shown in Table 1. Figure 4 The unit arrangement shown is mapped vertically onto the sphere, and the structure after arrangement is as follows Figure 1 shown.

[0041] Table 1 Relationship between phase and geometric parameters of phase-controlled metasurface units

[0042] unit Theoretical phase (°) Actual phase (°) <![CDATA[t1(°)]]> <![CDATA[t2(°)]]> 1 -177.6 -177.6 61 50 2 2.8 2.9 5 15 3 113.4 113.7 84 65 4 -158.7 -160.5 56 47 5 -59.8 -59.3 74 58

[0043] In an embodiment of the present invention, each of the phase-modulated metasurface units 210 includes a conductive backplane layer located on the spherical structure 100 , and an intermediate dielectric layer and a conductive structure layer sequentially located on the conductive backplane layer.

[0044] Specifically, the conductive backplane layer is made of indium tin oxide (ITO), the intermediate dielectric layer is made of glass, and the conductive structure layer is made of silver.

[0045] That is to say, the conductive structure layer is located on the outer surface of the spherical structure. When designing, the conductive structure layer is made by making a Figure 5 The surface conductive structure shown is then mapped to the outer surface of the spherical structure by mapping. The surface conductive structure on the plane is arranged according to the above-mentioned phase control rules, and after being mapped to the spherical structure, it is also arranged according to the above-mentioned phase control rules. It should be understood that the above-mentioned plane refers to a finite plane hypersurface, and the finite plane hypersurface is mapped to the non-developable plane, that is, mapped to the spherical structure. Specific mapping methods may include vertical mapping, centripetal mapping, and longitude and latitude lines.

[0046] In an embodiment of the present invention, each of the phase-modulation metasurface units is mapped onto the spherical structure by vertical mapping.

[0047] like Figure 6 As shown, the conductive structure layer includes a first double ring 10 and a second double ring 20, and the first double ring 10 and the second double ring 20 are symmetrically arranged about the diagonal of the phase-controlled metasurface unit to form a non-closed ring, and a straight wire 30 and a rectangular frame wire 40 are arranged in the non-closed ring, and the two ends of the straight wire 30 are respectively connected to the first double ring 10 and the second double ring 20, and the straight wire 30 is arranged through the rectangular frame wire 40, and after passing through the rectangular frame wire 40, the rectangular frame wire 40 is divided into two new rectangular frame wires.

[0048] like Figure 6 As shown, the straight wire 30 is arranged on the diagonal line of the phase control metasurface unit, that is, Figure 5 The surface conductive structures shown are all multiple cubes on the large plane. The surface conductive structures are located on the square surface, and the straight wires 30 are located at the diagonal position of the square. Therefore, the angle between the straight wires 30 and the horizontal line is 45°.

[0049] According to the oblique polarization conversion theory, the straight conductor 30 at this angle can improve the broadband polarization conversion performance.

[0050] Specifically, the first double-ring 10 includes a first inner ring line 11 and a first outer ring line 12, the second double-ring 20 includes a second inner ring line 21 and a second outer ring line 22, the first inner ring line 11 and the second inner ring line 21 symmetrically enclose a non-closed inner ring, the first outer ring line 12 and the second outer ring line 22 symmetrically enclose a non-closed outer ring, there is a first distance between the first inner ring line 11 and the second inner ring line 21, there is a second distance between the first outer ring line 12 and the second outer ring line 22, the second distance is greater than the first distance, both ends of the straight wire 30 are respectively connected to the first inner ring line 11 and the second inner ring line 21, both the first inner ring line 11 and the second inner ring line 21 have a first arc angle t1, both the first outer ring line 12 and the second outer ring line 22 have a second arc angle t2, the first arc angle t1 and the second arc angle t2 are in a linear relationship, and the changes of both the first arc angle t1 and the second arc angle t2 can affect the regulated phase of the phase-regulated metasurface unit.

[0051] In an embodiment of the present invention, the relationship between the first arc angle and the second arc angle is:

[0052] t2 = 0.63 * t1 + 11.7,

[0053] where, t2 represents the second arc angle, and t1 represents the first arc angle.

[0054] As Figure 5 and Figure 6 shown, in an embodiment of the present invention, p can specifically be 5 mm, l1 can specifically be 3 mm, l2 can specifically be 4.2 mm, l3 can specifically be 0.8 mm, and w can specifically be 2\({0}\) μm.

[0055] At a line width of 2\({0}\) μm, in order to improve the polarization conversion efficiency, a rectangular frame structure is designed within the non-closed ring, as Figure 6 shown, the rectangular frame wire and the straight wire form a whole to jointly improve the polarization conversion efficiency.

[0056] In an embodiment of the present invention, the shape of the conductive structure layer includes a non-closed double-ring structure and / or a "middle" character shape.

[0057] Figure 5 The surface conductive structure shown in

[0058] As Figure 7As shown in the figure, the electric field wavefront phase distribution corresponding to three structures of spherical metasurface, PEC sphere, and PEC plane loaded with phase control units at a frequency of 20 GHz with a plane wave incident vertically along the -z direction in an embodiment of the present invention. After phase control, the electric field phase distribution of the spherical metasurface is on the same phase plane, similar to the electric field wavefront phase distribution of the PEC plane, effectively controlling the divergent phase of the PEC sphere to the same phase plane.

[0059] like Figure 8 As shown, the co-polarization and cross-polarization components of the bistatic RCS of the spherical metasurface loaded with the phase control unit are compared with the co-polarization components of the PEC sphere and PEC plane. At 20 GHz, in the 0° direction, the difference between the co-polarization and cross-polarization components of the spherical metasurface is about 27.6 dB, that is, 99.6% of the plane waves incident along the x-polarization are successfully converted into y-polarized waves, with a high polarization conversion effect, and the cross-polarization component is close to the co-polarization component of the PEC plane, with a difference of about 7.3 dB at the 0° azimuth.

[0060] like Figure 9 As shown in Figure 2, the cross-polarization component and co-polarization component of the RCS of a single station on the spherical metasurface loaded with a phase control unit vary with frequency, and its polarization conversion rate is calculated as follows: Figure 10 As shown, the polarization conversion rate is greater than 0.8 in the range of 15 GHz to 28.9 GHz, and has a wide bandwidth.

[0061] In summary, the non-developable curved surface metasurface device provided by the present invention forms phase-controlled metasurface units arranged according to phase control rules on the surface of the non-developable curved surface. The arrangement of the phase-controlled metasurface units is adjusted according to the phase that can achieve stealth, so that the non-developable curved surface metasurface device has the effect of virtually forming a flat ground stealth. Due to the setting of the conductive structure layer of each phase-controlled metasurface unit, the broadband polarization conversion efficiency can also be improved, and it has broad development prospects and important application value in the fields of electromagnetic protection, antenna design, radar detection, etc.

[0062] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A non-developable curved metasurface device, characterized in that: include: A spherical structure and a metasurface polarization converter formed on the spherical structure, wherein the metasurface polarization converter includes a plurality of phase-modulated metasurface units arranged on the spherical structure according to a phase-modulation rule, wherein the phase-modulation rule includes a relationship between a controlled phase of the phase-modulated metasurface unit and a position of the phase-modulated metasurface unit; The relationship between the control phase of the phase control metasurface unit and the position of the phase control metasurface unit is: Among them, α i represents the control phase of the i-th phase control metasurface unit, α0 represents the initial phase of the phase control metasurface unit, f0 represents the phase control frequency point, R represents the radius of the spherical structure, p represents the side length of the phase control metasurface unit, c represents the speed of light, and c = 3×10 8 m / s,x i Indicates the location of the i-th phase-controlled metasurface unit.

2. The non-developable curved metasurface device according to claim 1, characterized in that: Each of the phase-modulated metasurface units includes a conductive backplane layer located on the spherical structure, and an intermediate dielectric layer and a conductive structure layer sequentially located on the conductive backplane layer.

3. The non-developable curved metasurface device according to claim 2, characterized in that: The conductive backplane layer is made of indium tin oxide, the intermediate dielectric layer is made of glass, and the conductive structure layer is made of silver.

4. The non-developable curved metasurface device according to claim 2, characterized in that: The conductive structure layer includes a first double ring and a second double ring, and the first double ring and the second double ring are symmetrically arranged about the diagonal of the phase-control metasurface unit to form a non-closed ring. A straight wire and a rectangular frame wire are arranged in the non-closed ring, and the two ends of the straight wire are respectively connected to the first double ring and the second double ring, and the straight wire passes through the rectangular frame wire and divides the rectangular frame wire into two new rectangular frame wires after passing through the rectangular frame wire.

5. The non-developable curved metasurface device according to claim 4, characterized in that: The straight wire is arranged on the diagonal line of the phase control metasurface unit.

6. The non-developable curved metasurface device according to claim 4, characterized in that: The first double ring includes a first inner ring line and a first outer ring line, and the second double ring includes a second inner ring line and a second outer ring line. The first inner ring line and the second inner ring line symmetrically form a non-closed inner ring, and the first outer ring line and the second outer ring line symmetrically form a non-closed outer ring. The first inner ring line and the second inner ring line are spaced by a first distance, and the first outer ring line and the second outer ring line are spaced by a second distance. The second distance is greater than the first distance. The two ends of the straight wire are respectively connected to the first inner ring line and the second inner ring line. The first inner ring line and the second inner ring line both have a first arc angle, and the first outer ring line and the second outer ring line both have a second arc angle. The first arc angle and the second arc angle are in a linear relationship. Changes in the first arc angle and the second arc angle can affect the control phase of the phase-control metasurface unit.

7. The non-developable curved metasurface device according to claim 6, characterized in that: The relationship between the first arc angle and the second arc angle is: t2=0.63*t1+11.7, Wherein, t2 represents the second arc angle, and t1 represents the first arc angle.

8. The non-developable curved metasurface device according to claim 2, characterized in that: The shape of the conductive structure layer includes a non-closed double circular ring structure and / or a "Z"-shaped structure. The conductive structure layer includes a first double circular ring and a second double circular ring. The first double circular ring and the second double circular ring are symmetrically arranged about the diagonal of the phase-controlled metasurface unit to form a non-closed circular ring. A straight wire and a rectangular frame wire are arranged in the non-closed circular ring. The two ends of the straight wire are respectively connected to the first double circular ring and the second double circular ring, and the straight wire passes through the rectangular frame wire and divides the rectangular frame wire into two new rectangular frame wires after passing through the rectangular frame wire.

9. The non-developable curved metasurface device according to claim 1, characterized in that: Each of the phase-modulated metasurface units is mapped onto the spherical structure by vertical mapping.

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