Cylindrical luneberg lens antenna with azimuth plane and pitching plane scanning capability

Abstract

The invention discloses a cylindrical Luneberg lens antenna with azimuth plane and pitching plane scanning capability, which comprises a Luneberg lens, the Luneberg lens comprises a support plate and a plurality of dielectric plate units arranged on the support plate, the thickness of each dielectric plate unit is gradually changed, and the dielectric plate units are anisotropic; a first feed waveguide disposed on a side surface of the luneberg lens to perform linear polarization beam scanning; and the second feed waveguide is arranged at the bottom of the luneberg lens so as to carry out circular polarization beam scanning. According to the antenna, the scanning dimension of the cylindrical luneberg lens is expanded, beam scanning of an azimuth plane and a pitching plane is realized, and meanwhile, the advantages of simple feed and low cost of the antenna are reserved; and by using the anisotropic unit, the functions of the cylindrical luneberg lens and the polarizer are integrated into a single structure, so that the structural compactness is improved on the premise of not sacrificing the original beam scanning performance of the azimuth plane and the pitching plane. The invention relates to the technical field of antenna engineering.

Description

Technical Field

[0001] The present application relates to the field of antenna engineering technology, and in particular to a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities. Background Art

[0002] Millimeter-wave wireless communication technology, with its abundant spectrum resources, large bandwidth, and low latency, can effectively meet the stringent requirements of fifth-generation (5G) wireless systems for higher data rates and lower latency. However, millimeter-wave communications suffer from significant path loss, which requires the use of high-gain antennas to effectively compensate for these losses. In addition, to ensure signal coverage in a specific area, these antennas must also have powerful beam scanning capabilities. Luneburg lens antennas offer a range of advantages, including broadband, high gain, and good beam coherence. These characteristics make them an ideal candidate for overcoming the inherent challenges of millimeter-wave communications.

[0003] With the continuous advancement of vehicle-to-everything (V2X) technology, the demand for vehicle antennas capable of supporting multiple connections is increasing. In complex urban environments, vehicles need to communicate with surrounding vehicles, ground base stations, roadside units (ROSs), and low-altitude drones. This requires vehicle antennas to have quasi-endfire and linearly polarized radiation characteristics to ensure effective communication. Furthermore, the system integration of terrestrial and satellite communications can provide seamless global service, which is the development vision of the next-generation wireless communication network. Furthermore, due to the polarization diversity of space-based and ground-based systems, vehicle antennas also need to support circularly polarized radiation in the zenith direction, especially in remote suburban areas. These evolving requirements bring new challenges to vehicle antenna design. These antennas must not only achieve beam scanning in azimuth and elevation but also support multiple polarization characteristics to adapt to different environmental requirements.

[0004] The spherical Luneburg lens antenna can theoretically achieve 360° full-space beam scanning, but its large and bulky structure limits its integration in actual systems. This has promoted the development of cylindrical Luneburg lenses. The cylindrical Luneburg lens structure is more compact and easier to integrate, but the scanning dimension of the traditional cylindrical Luneburg lens is limited to a single plane (usually the azimuth plane). In order to expand the scanning capability of the cylindrical Luneburg lens, researchers have explored a variety of methods, such as lens antenna arrays, new two-dimensional hybrid beam scanning schemes that combine phased array antennas and lens antennas, and new frequency-scanned leakage wave antennas that use modulated Luneburg lenses as beamforming networks. Although these schemes have expanded the scanning dimension of the cylindrical Luneburg lens to a certain extent, they also have problems such as large lens size, complex design, and high cost.

[0005] Existing technical solutions for the design and implementation of circularly polarized lens antennas can be summarized as follows: directly using a circularly polarized feed, cascading a lens and a linear-circular polarizer, introducing an air gap in the lens structure, exciting two orthogonal modes with different phase constants, and using anisotropic elements. These designs generally suffer from the problem of limiting the scanning dimension to a single plane, making it difficult to meet the requirements for multi-dimensional beam steering in complex communication scenarios. Summary of the Invention

[0006] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities, which can expand the scanning dimension of the cylindrical Luneburg lens and integrate focusing and polarization conversion functions to improve structural compactness.

[0007] The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to the first aspect of the present application includes:

[0008] A Luneburg lens comprises a support plate and a plurality of dielectric plate units arranged on the support plate, wherein the thickness of each dielectric plate unit varies gradually and is anisotropic;

[0009] A first feeding waveguide is provided on a side of the Luneburg lens, and the first feeding waveguide is capable of rotating around a central axis of the Luneburg lens to perform linear polarization beam scanning;

[0010] A second feeding waveguide is arranged at the bottom of the Luneburg lens, the second feeding waveguide is inclined at 45 degrees relative to the central axis of the Luneburg lens, and the second feeding waveguide can move horizontally to perform circularly polarized beam scanning.

[0011] The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to the embodiment of the present application has at least the following beneficial effects: the antenna expands the scanning dimension of the cylindrical Luneburg lens, realizes azimuth and elevation beam scanning, and retains its advantages of simple feeding and low cost; and by using anisotropic units, the functions of the cylindrical Luneburg lens and the polarizer are cleverly integrated into a single structure. This design realizes the dual integration of focusing and polarization conversion functions, and improves the compactness of the structure without sacrificing the original beam scanning performance in azimuth and elevation.

[0012] According to some embodiments of the present application, the support plate is circular, the projection combination of each of the dielectric plate units along the z direction is located in the support plate, and the Luneburg lens is cylindrical as a whole.

[0013] According to some embodiments of the present application, the dielectric plate units are arranged equidistantly along the x-direction.

[0014] According to some embodiments of the present application, the thickness of each Luneburg lens gradually decreases along the x-direction, and the Luneburg lenses of different thicknesses have different refractive indices.

[0015] According to some embodiments of the present application, the number of layers of the Luneburg lens is 12, and the thickness of the Luneburg lens gradually decreases outward from the middle of the support plate.

[0016] According to some embodiments of the present application, the diameter of the support plate is 55 to 56 mm, the height of the Luneburg lens is 20 to 22 mm, and the thickness of the dielectric plate unit is 1 to 2 mm.

[0017] According to some embodiments of the present application, the support plate is provided with positioning holes for fixing to the test bracket.

[0018] According to some embodiments of the present application, the thickness of the support plate is 0.2 to 0.4 mm.

[0019] According to some embodiments of the present application, the first feeding waveguide rotates around the Luneburg lens to achieve beam scanning in a range of 360° in the azimuth plane, and the second feeding waveguide moves translationally to achieve waveguide scanning in a range of ±28° in the elevation plane.

[0020] According to the second aspect of the present application, a design method for the cylindrical Luneburg lens antenna having azimuth and elevation scanning capabilities includes:

[0021] Dividing the Luneburg lens into a plurality of cells with a period a;

[0022] Anisotropic units are introduced into the Luneburg lens, wherein the units have different dielectric constants in the x-polarization and y-polarization directions, thereby ensuring that the electromagnetic wave obtains the necessary phase difference when passing through the unit;

[0023] The dielectric constant distribution of the Luneburg lens under y-polarization is designed to follow the Luneburg law and the thickness b of each dielectric plate unit is calculated;

[0024] The dielectric constant of the Luneburg lens under x-polarization is uniquely derived from the dielectric constant of the Luneburg lens under y-polarization;

[0025] The diameter of the Luneburg lens and the size of the dielectric plate unit are optimized, and the phase difference between the two polarized waves is adjusted to 90°.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and constitute a part of the specification. Together with the embodiments disclosed in this application, they are used to explain the technical solutions disclosed in this application and do not constitute a limitation on the technical solutions disclosed in this application.

[0028] Figure 1 A three-dimensional diagram of a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to an embodiment of the first aspect of the present application;

[0029] Figure 2 This is a schematic diagram of a ray tracing simulation when parallel light is incident along the positive direction of the x-axis in a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to an embodiment of the first aspect of the present application;

[0030] Figure 3 This is a schematic diagram of a ray tracing simulation when parallel light is incident along the negative z-axis in a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to an embodiment of the first aspect of the present application;

[0031] Figure 4 A graph showing the variation of the dielectric constant (εx and εy) of the Luneburg lens in the x-polarization and y-polarization directions with the thickness of the cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to the first embodiment of the present application;

[0032] Figure 5 The dielectric constant distribution curves of the cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities under x and y polarizations according to the first embodiment of the present application, as well as the dielectric constant distribution curve of the traditional Luneburg lens itself;

[0033] Figure 6 A graph showing changes in reflection coefficient and axial ratio when the position (fx, fy) of the second feeding waveguide in the cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to the first aspect of the present application is moved in steps of 10 mm along the x-axis, y-axis, and φ = 45°, respectively;

[0034] Figure 7 For the cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to the first aspect of the present application, the simulated and tested 30 GHz radiation patterns in the xoz plane, yoz plane, and D plane (φ = 45°) when the position (fx, fy) of the second feed waveguide is moved in 10 mm steps along the x-axis, y-axis, and φ = 45° direction, respectively;

[0035] Figure 8 The reflection coefficients of the cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities obtained by simulation and testing when the first feeding waveguide rotates along the circumference of the Luneburg lens by φx in the embodiment of the first aspect of the present application;

[0036] Figure 9 In the cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities in the first embodiment of the present application, the radiation pattern simulated and tested at 30 GHz when the first feeding waveguide rotates φx along the circumference of the Luneburg lens.

[0037] Reference numerals: 1 - Luneburg lens, 21 - first feeding waveguide, 22 - second feeding waveguide. DETAILED DESCRIPTION

[0038] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0039] In the description of this application, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0040] In the description of this application, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0041] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0042] In the description of this application, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0043] Millimeter-wave wireless communication technology, with its abundant spectrum resources, large bandwidth, and low latency, can effectively meet the stringent requirements of fifth-generation (5G) wireless systems for higher data rates and lower latency. However, millimeter-wave communications suffer from significant path loss, which requires the use of high-gain antennas to effectively compensate for these losses. In addition, to ensure signal coverage in a specific area, these antennas must also have powerful beam scanning capabilities. Luneburg lens antennas offer a range of advantages, including broadband, high gain, and good beam coherence. These characteristics make them an ideal candidate for overcoming the inherent challenges of millimeter-wave communications.

[0044] With the continuous advancement of vehicle-to-everything (V2X) technology, the demand for vehicle antennas capable of supporting multiple connections is increasing. In complex urban environments, vehicles need to communicate with surrounding vehicles, ground base stations, roadside units (ROSs), and low-altitude drones. This requires vehicle antennas to have quasi-endfire and linearly polarized radiation characteristics to ensure effective communication. Furthermore, the system integration of terrestrial and satellite communications can provide seamless global service, which is the development vision of the next-generation wireless communication network. Furthermore, due to the polarization diversity of space-based and ground-based systems, vehicle antennas also need to support circularly polarized radiation in the zenith direction, especially in remote suburban areas. These evolving requirements bring new challenges to vehicle antenna design. These antennas must not only achieve beam scanning in azimuth and elevation but also support multiple polarization characteristics to adapt to different environmental requirements.

[0045] The spherical Luneburg lens antenna can theoretically achieve 360° full-space beam scanning, but its large and bulky structure limits its integration in actual systems. This has promoted the development of cylindrical Luneburg lenses. The cylindrical Luneburg lens structure is more compact and easier to integrate, but the scanning dimension of the traditional cylindrical Luneburg lens is limited to a single plane (usually the azimuth plane). In order to expand the scanning capability of the cylindrical Luneburg lens, researchers have explored a variety of methods, such as lens antenna arrays, new two-dimensional hybrid beam scanning schemes that combine phased array antennas and lens antennas, and new frequency-scanned leakage wave antennas that use modulated Luneburg lenses as beamforming networks. Although these schemes have expanded the scanning dimension of the cylindrical Luneburg lens to a certain extent, they also have problems such as large lens size, complex design, and high cost.

[0046] Existing technical solutions for the design and implementation of circularly polarized lens antennas can be summarized as follows: directly using a circularly polarized feed, cascading a lens and a linear-circular polarizer, introducing an air gap in the lens structure, exciting two orthogonal modes with different phase constants, and using anisotropic elements. These designs generally suffer from the problem of limiting the scanning dimension to a single plane, making it difficult to meet the requirements for multi-dimensional beam steering in complex communication scenarios.

[0047] In this regard, the present application proposes a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities. This antenna expands the scanning dimension of the cylindrical Luneburg lens, realizes azimuth and elevation beam scanning, while retaining its advantages of simple feeding and low cost; and by using anisotropic units, cleverly integrates the functions of the cylindrical Luneburg lens and the polarizer into a single structure. This design realizes the dual integration of focusing and polarization conversion functions, and improves the compactness of the structure without sacrificing the original beam scanning performance in azimuth and elevation.

[0048] Reference Figure 1 The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities in the first embodiment of the present application includes a Luneburg lens 1, a first feed waveguide 21, and a second feed waveguide 22. The Luneburg lens 1 includes a support plate and a plurality of dielectric plate units disposed on the support plate, each of which has a gradually varying thickness and anisotropic properties. The Luneburg lens allows electromagnetic wave signals to pass through, and the electromagnetic wave signals are refracted by the Luneburg lens so as to be focused at the edge of the Luneburg lens 1.

[0049] The first feeding waveguide 21 is provided on a side of the Luneburg lens 1 , and the first feeding waveguide 21 can rotate around the central axis of the Luneburg lens 1 to perform linear polarization beam scanning.

[0050] The second feeding waveguide 22 is arranged at the bottom of the Luneburg lens 1 . The second feeding waveguide 22 is inclined at 45° relative to the central axis of the Luneburg lens. The second feeding waveguide 22 can move horizontally to perform circularly polarized beam scanning.

[0051] Thus, the Luneburg lens 1 adopts linearly polarized rectangular waveguide feeding in both the azimuth plane and the elevation plane. The azimuth plane specifically refers to the xoy plane, and the elevation plane specifically refers to the plane perpendicular to the xoy plane and parallel to the z-axis. In this embodiment, by utilizing the focusing ability of the Luneburg lens 1 in the elevation plane itself, and combining the traditional one-dimensional beam scanning scheme of the Luneburg lens 1 in the azimuth plane with the two-dimensional beam scanning scheme of the gradient refractive index flat lens in the elevation plane, the scanning dimension of the cylindrical Luneburg lens is expanded while retaining its advantages of simple feeding and low cost. In addition, a highly integrated cylindrical Luneburg lens is constructed by using anisotropic dielectric plate units, and the functions of the cylindrical Luneburg lens and the polarizer are integrated into a single structure in the elevation plane. This design realizes the dual integration of focusing and polarization conversion functions, and improves the compactness of the structure without sacrificing the original beam scanning performance of the azimuth and elevation planes.

[0052] Furthermore, the support plate is circular, the thickness of each dielectric plate unit is gradually changed and anisotropic, and the Luneburg lens 1 is cylindrical as a whole.

[0053] Furthermore, the dielectric plate units are arranged equidistantly along the x-direction to keep the spacing between the Luneburg lenses consistent.

[0054] Furthermore, the thickness of each dielectric plate unit gradually decreases along the x-direction, and dielectric plate units of different thicknesses have different refractive indices, so that when a signal passes through dielectric plates at different positions, the dielectric plates have different refractive effects on the signal.

[0055] Furthermore, the Luneburg lens has 12 layers, and the thickness of the Luneburg lens dielectric plate gradually decreases from the middle of the support plate outward. To prevent the dielectric plate from being too thin, the outermost dielectric plate unit can also be removed and replaced with an air layer.

[0056] Specifically, the diameter of the support plate is 55 to 56 mm, the height of the Luneburg lens is 20 to 22 mm, and the thickness of the dielectric plate is 1 to 2 mm.

[0057] Furthermore, the support plate is provided with positioning holes for fixing to the test bracket. The thickness of the support plate is 0.2 to 0.4 mm.

[0058] Furthermore, the first feeding waveguide 21 rotates around the Luneburg lens 1 once to achieve beam scanning in a range of 360° in the azimuth plane, and the second feeding waveguide 22 moves translationally to achieve waveguide scanning in a range of ±28° in the elevation plane.

[0059] Furthermore, the first feeding waveguide 21 and the second feeding waveguide 22 are both linearly polarized rectangular waveguide antennas. During the azimuth plane beam scanning process, the electric field of the waveguide is always parallel to the z-axis.

[0060] In an embodiment of the second aspect of the present application, a design method for the cylindrical Luneburg lens antenna having azimuth and elevation scanning capabilities includes the following steps:

[0061] S100. Divide the Luneburg lens 1 into a plurality of cells with a period a;

[0062] S200. Introducing anisotropic units into the Luneburg lens 1, wherein these units have different dielectric constants in the x-polarization and y-polarization directions, ensuring that the electromagnetic wave obtains the necessary phase difference when passing through the unit;

[0063] S300. Designing the dielectric constant distribution of the Luneburg lens under y-polarization to follow the Luneburg law and calculating the thickness b of each dielectric plate;

[0064] S400. Once the dielectric constant of the Luneburg lens under y polarization is obtained, the dielectric constant of the Luneburg lens under x polarization can be uniquely derived from the dielectric constant of the Luneburg lens under y polarization;

[0065] S500. Optimize the diameter of the Luneburg lens and the size of the dielectric plate. Adjust the phase difference between the two polarized waves to 90°.

[0066] Reference Figure 2 When light in the x-direction is incident on Luneburg lens 1, it is focused at the focal point on the lens's circumferential surface after passing through Luneburg lens 1, which is consistent with the definition of a Luneburg lens. This indicates that the cylindrical Luneburg lens has good focusing performance and beam scanning capabilities in the azimuth plane.

[0067] Reference Figure 3 , light still has a clear focal zone after passing through Luneburg lens 1 in the elevation plane, although its focusing performance is not as perfect as in the azimuth plane. This is reasonable because, although the relative permittivity distributions of cylindrical Luneburg lenses and gradient-index flat lenses are very similar, there are still some slight deviations, which may cause phase aberrations. However, these deviations have little effect on the focusing performance of the cylindrical Luneburg lens in the elevation plane, and the image quality is good. These results further confirm that the cylindrical Luneburg lens can achieve focusing in the elevation plane in addition to its azimuth focusing capability.

[0068] Reference Figure 4 The dielectric constant distribution of these units in the x-polarization and y-polarization directions is different, which ensures that the electromagnetic wave can obtain the necessary phase difference when passing through the unit, and thus can introduce the required 90° phase difference between the orthogonal components to achieve circular polarization.

[0069] It is worth noting that εx and εy are functionally related to the thickness of the Luneburg lens. Therefore, once the dielectric constant distribution of the highly integrated cylindrical lens in one polarization direction (x or y polarization) is determined, the dielectric constant distribution in the other polarization direction (y or x polarization) is also uniquely determined. The designed highly integrated cylindrical Luneburg lens is designed so that the dielectric constant distribution under y polarization follows the Luneburg law. Subsequently, by Figure 4 The curve in determines the corresponding Luneburg lens thickness b. Figure 5 1 is the dielectric constant distribution curve of the highly integrated cylindrical Luneburg lens in this embodiment under x and y polarizations, as well as the dielectric constant distribution curve of the traditional Luneburg lens itself.

[0070] Table 1 shows the thickness of each dielectric plate in the embodiment of the present invention, wherein the dielectric plates are arranged from the inside to the outside.

[0071]

[0072] In order to fully evaluate the performance of the highly integrated cylindrical Luneburg lens, the second feeding waveguide 22 needs to be moved along the x-axis (φ = 0°), y-axis (φ = 90°) and φ = 45°. Figure 6 a), y-axis ( Figure 6 b), and φ=45°( Figure 6The reflection coefficient and axial ratio simulated and tested by the embodiment of the present invention when moving in the direction of (c) with a step size of 10 mm. The tested -10 dB overlap impedance bandwidth is 26.00% (27.20–35.00 GHz), and the 3 dB overlap axial ratio bandwidth during beam scanning is 16.00% (28.40–33.20 GHz).

[0073] The second feeding waveguides 22 are respectively arranged along the x-axis ( Figure 7 a), y-axis ( Figure 7 b) and φ=45°( Figure 7 Simulated and tested 30GHz radiation patterns in the xoz, yoz, and D planes (φ = 45°) when moving in the direction c) with a 10mm step size. This embodiment of the present invention achieves a ±28° beam sweep range in the elevation plane, with a tested peak gain of 18.76dBic. Furthermore, near the main beam direction, the cross-polarization level remains below -18dB, demonstrating excellent circular polarization performance.

[0074] Figure 8 The simulated and measured reflection coefficients of the first feed waveguide 21 when it rotates along the lens circumference by φx are shown in Figure 1. The measured -10 dB overlap bandwidth is 26.00% (27.20–35.00 GHz). The bandwidth of a Luneburg lens antenna is primarily limited by the bandwidth of the feed source.

[0075] Figure 9 The radiation patterns simulated and measured at 30 GHz for the first feed waveguide 21 rotated along the lens circumference by φx clearly illustrate the proposed lens's beam scanning performance in the azimuth plane. The measured data closely matches the simulation results, with a maximum gain of 15.57 dBi and a gain fluctuation of 2.87 dB.

[0076] The embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities, characterized in that: include: A Luneburg lens comprises a support plate and a plurality of dielectric plate units arranged on the support plate, wherein the thickness of each dielectric plate unit varies gradually and is anisotropic; A first feeding waveguide is provided on a side of the Luneburg lens, and the first feeding waveguide is capable of rotating around a central axis of the Luneburg lens to perform linear polarization beam scanning; A second feeding waveguide is arranged at the bottom of the Luneburg lens, the second feeding waveguide is inclined at 45 degrees relative to the central axis of the Luneburg lens, and the second feeding waveguide can move horizontally to perform circularly polarized beam scanning.

2. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 1, characterized in that: The support plate is circular, the projection combination of each dielectric plate unit along the z direction is located in the support plate, and the Luneburg lens is cylindrical as a whole.

3. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 2, characterized in that: The Luneburg lenses are arranged at equal distances along the x-direction.

4. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 2, characterized in that: The thickness of each dielectric plate unit gradually decreases along the x-direction, and dielectric plate units of different thicknesses have different refractive indices.

5. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 4, characterized in that: The number of layers of the Luneburg lens is 12, and the thickness of the dielectric plate unit gradually decreases outward from the middle of the support plate.

6. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 4, characterized in that: The diameter of the support plate is 55 to 56 mm, the height of the Luneburg lens is 20 to 22 mm, and the thickness of the dielectric plate unit is 2 to 3 mm.

7. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 1, characterized in that: The support plate is provided with positioning holes for fixing to the test bracket.

8. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 1, characterized in that: The thickness of the support plate is 0.2 to 0.4 mm.

9. The cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to claim 1, characterized in that: The first feeding waveguide rotates around the Luneburg lens to achieve beam scanning in a range of 360° in the azimuth plane, and the second feeding waveguide moves translationally to achieve waveguide scanning in a range of ±28° in the elevation plane.

10. A design method for a cylindrical Luneburg lens antenna with azimuth and elevation scanning capabilities according to any one of claims 1 to 9, characterized in that: include: Dividing the Luneburg lens into a plurality of units with a period of a; Anisotropic units are introduced into the Luneburg lens, wherein the units have different dielectric constants in the x-polarization and y-polarization directions, thereby ensuring that the electromagnetic wave obtains the necessary phase difference when passing through the unit; The dielectric constant distribution of the Luneburg lens under y-polarization is designed to follow the Luneburg law and the thickness b of each dielectric plate unit is calculated; The dielectric constant of the Luneburg lens under x-polarization is uniquely derived from the dielectric constant of the Luneburg lens under y-polarization; The diameter and size of the Luneburg lens are optimized, and the phase difference between the two polarized waves is adjusted to 90°.

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