A Compact Circularly Polarized Luneburg Lens Antenna

Abstract

The present invention discloses a compact circularly polarized Luneburg lens antenna, which includes a Luneburg lens and a plurality of feed sources. The Luneburg lens includes a plurality of cylindrical units. The height directions of the cylindrical units are parallel, and the centers of the bottom surfaces of the cylindrical units are distributed on a plurality of concentric virtual circles on the same plane. A first air gap is formed between any two adjacent virtual circles. Each feed source surrounds the Luneburg lens, and the radiation direction of each feed source is aligned with the central axis position of the Luneburg lens. The feed source radiates electromagnetic waves at 45° relative to the plane where the virtual circle is located. In the present invention, the incident spherical wave is converted into an outgoing plane wave by the Luneburg lens, and through the 45° oblique incidence of the feed source, the incident linear polarized wave can be changed into a circularly polarized wave at the radiation aperture of the Luneburg lens, thereby realizing the function of circular polarization. By switching the working feed source, multi-beam scanning can be achieved, so a multi-beam antenna capable of realizing circular polarization is obtained. The present invention is widely applied to the technical field of electronic devices.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic devices, and particularly to a compact circularly polarized Luneburg lens antenna. Background Art

[0002] With the development of the fifth-generation mobile communication system (5G), the requirements for high speed and low latency are getting higher and higher, but the spectrum resources are limited. Therefore, the use of MIMO (multiple-input multiple-output) technology in the millimeter-wave band has become a way to solve the conflict. As one of the key technologies of 5G, MIMO technology has received extensive attention, and a multi-beam antenna that can generate multiple independent high-gain directional beams is the key to realizing MIMO technology.

[0003] Circularly polarized antennas have several important advantages: 1. Circularly polarized antennas can effectively combat multipath interference or fading; 2. Circularly polarized antennas can reduce the "Faraday rotation" effect caused by the ionosphere, which will cause significant signal loss if a linearly polarized antenna is used; 3. When using a circularly polarized antenna, there is no need for a strict direction between the transmitting and receiving antennas, and the intensity of the received signal is quite constant.

[0004] In the current related technologies, there is no multi-beam antenna that can integrate the advantages of circularly polarized antennas. Summary of the Invention

[0005] Aiming at the above at least one technical problem, an object of the present invention is to provide a compact circularly polarized Luneburg lens antenna, including:

[0006] A Luneburg lens; the Luneburg lens includes a plurality of cylindrical units, the height directions of the cylindrical units are parallel, the centers of the bottom surfaces of the cylindrical units are distributed on a plurality of concentric virtual circles on the same plane, and a first air gap is formed between any two adjacent virtual circles;

[0007] A plurality of feed sources; each of the feed sources surrounds the Luneburg lens, the radiation directions of the feed sources are aligned with the central axis position of the Luneburg lens, and the feed sources radiate electromagnetic waves at 45° with respect to the plane where the virtual circle is located.

[0008] Further, each of the feed sources is located on the same plane, the plane where each of the feed sources is located is parallel to the plane where the virtual circle is located, the radiation directions of the feed sources are aligned with the central axis position of the Luneburg lens, and the included angles between the radiation directions of any two adjacent feed sources are equal.

[0009] Further, the cylindrical units distributed on the same virtual circle form a plurality of close-packed combinations, each close-packed combination includes a plurality of closely arranged cylindrical units, and a second air gap is formed between any two adjacent close-packed combinations distributed on the same virtual circle.

[0010] Further, each of the second air gaps is distributed at the intersection positions of each of the virtual circles and a set of virtual grating arrays; the widths and periods of the virtual grating arrays are respectively fixed values.

[0011] Further, the heights of the cylindrical units are equal, and the lengths of the first air gaps in the diameter direction of the virtual circles are not all equal.

[0012] Further, the diameters of the cylindrical units distributed on the same virtual circle are equal, and the diameters of the cylindrical units distributed on the more inner virtual circles are larger.

[0013] Further, the feed source includes a waveguide part, a twisting part, and a radiation part; the waveguide part is a cuboid, the cross-section of the radiation part has the same shape as the cross-section of the waveguide part, and a spatial angle of 45° is formed between a symmetry axis of the cross-section of the radiation part and a corresponding symmetry axis of the cross-section of the waveguide part, and the twisting part connects the waveguide part and the radiation part.

[0014] Further, through holes and blind holes are formed in the waveguide part, the through holes are used for connecting coaxial probes, and the blind holes are used for installing coaxial mode converters.

[0015] Further, the feed source is made of copper, and the cylindrical units are made of photosensitive resin.

[0016] Further, the compact circularly polarized Luneburg lens antenna further includes a connection structure, and the connection structure is used for assembling the Luneburg lens and each of the feed sources so that the Luneburg lens and each of the feed sources maintain a fixed positional relationship with each other.

[0017] The beneficial effects of the present invention are as follows: In the Luneburg lens antenna in the embodiment, through the refraction effect of the Luneburg lens, the effect of changing the incident spherical wave into an outgoing plane wave is achieved, so that the gain becomes larger and the lobes become narrower. By the 45° oblique incidence of the feed source, the incident linearly polarized wave can be changed into a circularly polarized wave at the radiation aperture of the Luneburg lens, so as to achieve the function of circular polarization. By switching the working feed source, multi-beam scanning can be realized. Therefore, the Luneburg lens antenna in this embodiment is a multi-beam antenna capable of realizing circular polarization, and has the advantages of being easy to manufacture and easy to compact. Description of the Drawings

[0018] Figure 1 It is the overall view of the compact circularly polarized Luneburg lens antenna in the embodiment;

[0019] Figure 2 It is the structural diagram of the Luneburg lens in the embodiment;

[0020] Figure 3Schematic diagram of the positional relationship between the Luneburg lens and the feed in the embodiment;

[0021] Figure 4 Structural diagram of the feed in the embodiment;

[0022] Figure 5 Schematic diagram of the close-packed combination in the embodiment;

[0023] Figure 6 Schematic diagram of the second air gap in the embodiment;

[0024] Figure 7 Schematic diagram of the connection structure in the embodiment;

[0025] Figure 8 Echo loss - operating frequency and axial ratio coefficient - operating frequency simulation and measured result diagram of the embodiment of the present invention;

[0026] Figure 9(a) is the simulation and measured radiation pattern of the embodiment of the present invention at an operating frequency of 32 GHz with theta = 90 deg;

[0027] Figure 9(b) is the simulation and measured radiation pattern of the embodiment of the present invention at an operating frequency of 35 GHz with theta = 90 deg;

[0028] Figure 9(c) is the simulation and measured radiation pattern of the embodiment of the present invention at an operating frequency of 37 GHz with theta = 90 deg;

[0029] Figure 10 Multi-beam scanning radiation pattern of the embodiment of the present invention at 35 GHz, theta = 90 deg. Detailed implementation manner

[0030] In this embodiment, the overall view of the compact circularly polarized Luneburg lens antenna is as Figure 1 shown, including a Luneburg lens and a plurality of feeds.

[0031] Referring to Figure 2 , the Luneburg lens includes a plurality of cylindrical units. The height directions of the cylindrical units are parallel, and the centers of the bottom surfaces of the cylindrical units are distributed on a plurality of concentric virtual circles on the same plane. In this embodiment, the virtual circle refers to a hypothetical reference position, which can be obtained by geometrically connecting the centers of the bottom surfaces of the corresponding cylindrical units, and there may be no physical object related to the virtual circle in the Luneburg lens antenna.

[0032] In this embodiment, a photosensitive resin material with a dielectric constant of 2.9 can be used to manufacture the cylindrical units. The diameters of each cylindrical unit can be different. Specifically, the diameters of the cylindrical units distributed on the same virtual circle are equal, and the diameters of the cylindrical units on the virtual circles closer to the center are larger. Inside the innermost virtual circle, that is, at the center position of all virtual circles, a cylindrical unit can be set, and the diameter of this cylindrical unit is larger than that of other cylindrical units. In this embodiment, the heights of each cylindrical unit are equal.

[0033] Figure 2 In total, there are 10 virtual circles, that is, there are 10 types of cylindrical units with different diameters, that is, all the cylindrical units are arranged in 10 layers, and each layer corresponds to a virtual circle. There is an air gap between adjacent layers of cylindrical units, which is called the first air gap in this embodiment.

[0034] Refer to Figure 1 , each feed source surrounds the Luneburg lens, and the radiation directions of each feed source are aligned with the central axis position of the Luneburg lens. Specifically, refer to Figure 3 , each feed source is located on the same plane, and the plane where each feed source is located is parallel to the plane where the virtual circle is located. Figure 3 A total of 7 feed sources are provided in , and the radiation directions of each feed source are OA, OB, OC, OD, OE, OF, and OG respectively. They all intersect the central axis of the Luneburg lens at point O. Therefore, points O, A, B, C, D, E, F, and G are all on a plane, and this plane is parallel to the plane where the virtual circle is located.

[0035] Refer to Figure 3 , the included angle between the radiation directions of any two adjacent feed sources is equal, that is, ∠AOB = ∠BOC = ∠COD = ∠DOE = ∠EOF = ∠FOG = θ0, and θ0 = 20° in this embodiment. By Figure 3 The position shown and setting θ0 = 20° can enable the radiation areas of each feed source to evenly cover a region of the Luneburg lens. When scanning, by switching the working feed sources, multi-beam scanning within the range of ±67° can be achieved.

[0036] In this embodiment, the structure of the feed source is as shown in Figure 4 , including a waveguide part, a torsion part, and a radiation part. Among them, the waveguide part is a cuboid, so the cross-section of the waveguide part is a rectangle, and the cross-section of the radiation part is the same as that of the waveguide part, that is, the cross-section of the radiation part is also a rectangle. The waveguide part and the radiation part are connected by the torsion part. Among them, the feed source is made of copper, and through an integrated forming processing method, for example, after casting the waveguide part, the torsion part, and the radiation part, heating the torsion part and the radiation part to the target temperature, and then fixing the waveguide part, applying a torsional mechanical force to the radiation part, so as to form aFigure 4 The feed of the structure shown

[0037] Figure 4 The two dashed lines in are respectively the symmetry axes parallel to the long side of the cross-section of the waveguide part and the corresponding symmetry axes of the cross-section of the radiation part, that is, the symmetry axes parallel to the long side of the cross-section of the radiation part Figure 4 The included angle formed by these two dashed lines in is 45°. This makes that when the cross-section of the waveguide part is perpendicular to the plane where the virtual circle is located, the angle formed by the cross-section of the radiation part and the plane where the virtual circle is located is 45°. Therefore, each feed radiates electromagnetic waves at 45° relative to the plane where the virtual circle is located

[0038] Referring to Figure 3 , there is 1 through hole and 4 blind holes in the waveguide part of each feed. The through hole is used to connect the coaxial probe, and the 4 blind holes are threaded holes for installing the coaxial-to-waveguide connector. The coaxial-to-waveguide connector can also be connected to a coaxial cable to receive the signal to be radiated. By adjusting the depth of insertion of the coaxial probe into the through hole, the impedance matching between the feed and the coaxial cable can be carried out

[0039] Therefore, the Luneburg lens in this embodiment is a discrete layered structure. The combination of the width of the first air gap and the radius size of the cylindrical unit is different, and the equivalent dielectric constant value of the overall Luneburg lens is different. Therefore, the combination of the width of the first air gap and the radius size of the cylindrical unit can be designed according to the theoretical requirements of the dielectric constant change law of the Luneburg lens. In this embodiment, for a certain unit cylinder, taking this unit cylinder as the center, the result calculated by "half of the width of the air gap adjacent to the left of this unit cylinder + the diameter of this unit cylinder + half of the width of the air gap on the right" is used as the radius size of this unit cylinder. Then the size of each unit cylinder in the diameter direction is the same. The radius size of the unit cylinder can be designed and adjusted as needed. So when different sizes of unit cylinders are obtained, the widths of the corresponding air gaps can be unequal. And in this embodiment, the diameters of the cylindrical units gradually increase from the outside to the inside, and the number of cylindrical units in the same layer gradually decreases from the outside to the inside, meeting the theoretical requirements of the dielectric constant change law of the Luneburg lens, so that Figure 2 The structure shown can realize the function of converting the incident spherical wave into an outgoing plane wave, that is Figure 2 The structure shown is a Luneburg lens

[0040] In this embodiment, when the feed radiates electromagnetic waves to the Luneburg lens at an inclination angle of 45° relative to the plane of the Luneburg lens (i.e., the plane parallel to the virtual circle, such as the cross-sectional plane of the waveguide part in the feed), when the electromagnetic waves enter the Luneburg lens, they will be decomposed into x-axis and y-axis components perpendicular to each other. Since the phase velocities of the electromagnetic waves propagating in the medium (cylindrical unit) and air (second air gap) of the Luneburg lens are different, the x-axis and y-axis components of the electromagnetic waves will form a 90° phase difference when reaching the radiation aperture. When two linearly polarized waves that are perpendicular to each other and have a phase difference of 90° are synthesized when exiting the Luneburg lens, the required circularly polarized wave is obtained.

[0041] Therefore, in this embodiment, through the refraction effect of the Luneburg lens, the effect of changing the incident spherical wave into an outgoing plane wave is realized, so that the gain increases and the lobes become narrower. By the 45° oblique incidence of the feed, the incident linearly polarized wave can be changed into a circularly polarized wave at the radiation aperture of the Luneburg lens, thus realizing the function of circular polarization. By switching the working feed, multi-beam scanning can be realized. Therefore, the Luneburg lens antenna in this embodiment is a multi-beam antenna capable of realizing circular polarization.

[0042] On the other hand, the Luneburg lens in this embodiment can be obtained by combining cylindrical units, and both the cylindrical units and the feed can be obtained by integral forming technologies such as 3D printing. Therefore, it is easy to process and manufacture and easy to compact.

[0043] In this embodiment, the distribution of the cylindrical units on the same layer on their corresponding virtual circles is not uniform, and there are cases where multiple cylindrical units are closely arranged and there is a certain distance between two certain cylindrical units. This arrangement state of the cylindrical units forms Figure 5 the shown close-packed combination. A close-packed combination includes multiple closely packed cylindrical units. Close-packed can mean that the cylindrical units are closely fitted and the sides of adjacent cylindrical units are tangent. There is a space greater than the diameters of several cylindrical units where there are no cylindrical units between any two adjacent close-packed combinations on the same virtual circle, and this space forms the second air gap.

[0044] In this embodiment, the distribution law of the second air gap is as shown in Figure 6 shown. Figure 6 This is the situation seen from one end of the Luneburg lens. Figure 6 The virtual grid array shown in [ID] includes multiple virtual rectangles. In this embodiment, the virtual grid array and the virtual rectangles are hypothetical virtual positions used to determine the positional relationship of the components in the Luneburg lens antenna. This virtual position can be obtained by geometric methods, and there may be no physical objects related to the virtual grid array or the virtual rectangles in the Luneburg lens antenna.

[0045] Refer to Figure 6, the width of the virtual grating array, that is, the width of each virtual rectangle in the virtual grating array is a fixed value w1, and the distance between any two adjacent virtual rectangles is a fixed value w2. Therefore, the period of the virtual grating array is a fixed value w1 + w2.

[0046] After making the virtual grating array and the virtual circle in Figure 6 , no cylindrical units are provided at the positions where the virtual circle intersects with each virtual rectangle in the virtual grating array (thus forming a second air gap due to the absence of cylindrical units), while densely arranged cylindrical units are provided at the positions where the virtual circle does not intersect with the virtual grating array (thus forming a densely arranged combination).

[0047] By setting Figure 6 the multiple second air gaps shown, on the basis of not affecting the function of the Luneburg lens composed of each cylindrical unit to transform the incident spherical wave into an outgoing plane wave, the circular polarization effect can be strengthened.

[0048] In this embodiment, reference can be made to Figure 7 , and connection structures such as plastic strips or plastic plates are used at both ends of the Luneburg lens to assemble each cylindrical unit in the Luneburg lens. Another connection structure (not shown in the accompanying drawings of the specification) can be used to fix each feed source to the Luneburg lens in the same way, so that the Luneburg lens and each feed source maintain a fixed positional relationship with each other.

[0049] Through Figure 1 , Figure 2 , Figure 3 and Figure 4 the structures shown, the planar Luneburg lens antenna of the present invention has the following technical effects:

[0050] (1) High gain, narrow beam, low side lobe: The spherical wave emitted from the feed source forms an equiphase plane wave on the output aperture surface after being refracted by the Luneburg lens, thereby greatly improving the gain and directivity of the beam;

[0051] (2) Circular polarization: The wave emitted from the feed source is a linearly polarized wave. By being placed at a 45° inclination with respect to the lens, the incident linearly polarized wave will form a circularly polarized wave after passing through the lens.

[0052] (3) Wide scanning angle: By placing seven feed sources spaced 20° apart at the focal points on the lens surface, multi-beam scanning within the range of ±67° can be achieved by switching the feed sources during implementation;

[0053] (3) Simple structure and easy to process and manufacture: Through the equivalent permittivity calculation method, the whole lens can be realized by using only one medium, which reduces the design complexity of the lens and has more practical value. Through the 3D printing process, it is easy to process, with a small overall size and light weight, overcoming the disadvantages of large volume, heaviness and difficult fixation when using a traditional spherical Luneburg lens.

[0054] The technical effects of the present invention are mainly brought about by the structure of the present invention, and are also related to the specific values of the following parameters: the radii r1 to r of the ten slender cylindrical units constituting the Luneburg lens 10 , the overall radius R of the lens, the length L1 of the 45° inclined part of the rectangular waveguide, the length L2 of the twisted part, and the length L3 of the horizontal part.

[0055] Table 1

[0056] Parameter <![CDATA[r1]]> <![CDATA[r 2]]> <![CDATA[r 3]]> <![CDATA[r 4]]> <![CDATA[r 5]]> <![CDATA[r 6]]> <![CDATA[r 7]]> <![CDATA[r 8]]> <![CDATA[r 9]]> Value (mm) 1.487 1.478 1.456 1.424 1.377 1.312 1.220 1.093 0.900 Parameter <![CDATA[r 10 > R <![CDATA[L1]]> <![CDATA[L2]]> <![CDATA[L3]]> Value (mm) 0.556 17.4 2.15 6.46 10.77

[0057] Design according to the above values, and simulate the designed compact circularly polarized Luneburg lens antenna. The simulation software is CST studio suite. The simulation results are as Figures 8 - 10 shown.

[0058] Figure 8 shows the simulation and measured results diagrams of the return loss - operating frequency and axial ratio coefficient - operating frequency of the embodiment of the present invention. It can be clearly seen from the figure that the measured results are highly consistent with the simulation results. From 33.1 GHz to 37.3 GHz, the |S 11 | parameter is below -10 dB, and the impedance bandwidth is 12%. Between 31 GHz and 37.1 GHz, the axial ratio coefficient is less than 3, and the axial ratio bandwidth is 17.4%. This shows that the proposed compact circularly polarized Luneburg lens antenna can achieve a good linear polarization - circular polarization conversion effect between the frequencies of 31 GHz and 37.1 GHz, and has a relatively wide operating bandwidth. Combining the two sets of coefficients, it can be obtained that the overlapping bandwidth between the impedance bandwidth and the axial ratio bandwidth is 11.4%, that is, from 33.1 GHz to 37.1 GHz, which is the operating bandwidth of the circularly polarized Luneburg lens antenna.

[0059] Figure 9 shows the simulated and measured radiation patterns of the embodiment of the present invention at theta = 90 deg at different frequencies. At the center frequency of 35 GHz, a pencil-shaped radiation pattern can be observed, and the measured radiation pattern is highly consistent with the simulation results, as shown in Fig. 9(b). The case of 352 GHz is shown in Fig. 9(a), and the case of 37 GHz is shown in Fig. 9(c). The measured radiation pattern shows that the achieved gain is 13.1 dB, the 3 dB beamwidth is 13.7°, and the sidelobe level is below -12 dB. It can be seen that the proposed lens antenna can maintain the radiation characteristics of the Luneburg lens while achieving circular polarization. Good radiation patterns can also be obtained at 32 GHz and 37 GHz, further indicating that the circularly polarized Luneburg lens antenna has a wide operating bandwidth.

[0060] Figure 10 Figure shows the multi-beam scanning radiation pattern of the embodiment of the present invention at 35 GHz with theta = 90 deg. Referring to this figure, taking a single beam at φ = 0° as an example, a pencil-shaped pattern can be observed. It can be seen that the proposed circularly polarized Luneburg lens antenna can maintain good radiation characteristics of high gain, narrow beam, and low sidelobes on the premise of greatly reducing the processing difficulty. There are a total of 7 main beams in the figure, which are the results obtained after irradiating the lens with rectangular waveguide feeds placed at different positions. From the pattern curve, it can be seen that the presence of multiple rectangular waveguide feeds has little effect on a single beam, and the beams excited by different feeds can all maintain the same excellent radiation effect. The measured results are in good agreement with the simulation results. The results show that the multi-beam scanning range of the compact circularly polarized Luneburg lens antenna can cover 134°.

[0061] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or indirectly fixed or connected to the other feature. In addition, the up, down, left, right, etc. descriptions used in this disclosure are only relative to the mutual positional relationship of the components of this disclosure in the drawings. The singular forms "a", "the", and "said" used in this disclosure are also intended to include the plural forms, unless the context clearly indicates otherwise. In addition, unless otherwise defined, all technical and scientific terms used in this embodiment are equal to the meanings commonly understood by those skilled in the art of this technology. The terms used in the description of this embodiment of the specification are only for describing specific embodiments, and are not intended to limit the present invention. The term "and / or" used in this embodiment includes any combination of one or more of the related listed items.

[0062] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish elements of the same type from each other. For example, without departing from the scope of this disclosure, the first element may also be referred to as the second element, and similarly, the second element may also be referred to as the first element. The use of any and all examples or exemplary language ("for example", "such as", etc.) provided in this embodiment is only intended to better illustrate the embodiments of the present invention and will not impose a limitation on the scope of the present invention unless otherwise required.

[0063] It should be recognized that embodiments of the present invention can be implemented or carried out by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory computer-readable memory. The methods can be implemented in a computer program using standard programming techniques - including a non-transitory computer-readable storage medium configured with the computer program, where the storage medium so configured causes the computer to operate in a specific and predefined manner - in accordance with the methods and drawings described in the specific embodiments. Each program can be implemented in a high-level procedural or object-oriented programming language to communicate with the computer system. However, if desired, the program can be implemented in assembly or machine language. In any case, the language can be a compiled or interpreted language. In addition, for this purpose, the program is capable of running on a programmed application-specific integrated circuit.

[0064] In addition, the operations of the processes described in this embodiment can be performed in any suitable order, unless this embodiment otherwise indicates or is otherwise clearly inconsistent with the context. The processes described in this embodiment (or variations and / or combinations thereof) can be executed under the control of one or more computer systems configured with executable instructions and can be implemented as code (e.g., executable instructions, one or more computer programs, or one or more applications) executed commonly on one or more processors, by hardware, or a combination thereof. The computer program includes multiple instructions executable by one or more processors.

[0065] Further, the method can be implemented in any type of computing platform operatively connected to a suitable one, including but not limited to personal computers, minicomputers, mainframes, workstations, network or distributed computing environments, separate or integrated computer platforms, or communicating with charged particle tools or other imaging devices, etc. Aspects of the present invention can be implemented in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into the computing platform, such as a hard disk, optical read and / or write storage medium, RAM, ROM, etc., such that it can be read by a programmable computer and, when the storage medium or device is read by the computer, can be used to configure and operate the computer to perform the processes described herein. Further, the machine-readable code, or portions thereof, can be transmitted via wired or wireless networks. When such media include instructions or programs that implement the above-described steps in conjunction with a microprocessor or other data processor, the invention as described in this embodiment includes these and other different types of non-transitory computer-readable storage media. When programmed according to the methods and techniques of the present invention, the present invention also includes the computer itself.

[0066] A computer program can be applied to input data to perform the functions described in this embodiment, thereby transforming the input data to generate output data stored in non-volatile memory. The output information can also be applied to one or more output devices such as a display. In a preferred embodiment of the present invention, the transformed data represents physical and tangible objects, including a specific visual depiction of the physical and tangible objects generated on a display.

[0067] As described above, these are only the preferred embodiments of the present invention. The present invention is not limited to the above-described embodiments. As long as it achieves the technical effects of the present invention by equivalent means, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. Within the scope of protection of the present invention, its technical solutions and / or implementation manners can have various different modifications and changes.

Claims

1. A compact circularly polarized Luneburg lens antenna, characterized in that, Comprising: A Luneburg lens; the Luneburg lens includes a plurality of cylindrical units, the height directions of the cylindrical units are parallel, the center points of the bottom surfaces of the cylindrical units are distributed on a plurality of concentric virtual circles on the same plane, and a first air gap is formed between any two adjacent virtual circles; A plurality of feeders; Each of the feeders surrounds the Luneburg lens, the radiation direction of each feeder is aligned with the central axis position of the Luneburg lens, and the feeder radiates electromagnetic waves at 45° relative to the plane where the virtual circle is located; Each of the cylindrical units distributed on the same virtual circle forms a plurality of close-packed combinations, the close-packed combination includes a plurality of closely packed cylindrical units, and a second air gap is formed between any two adjacent close-packed combinations distributed on the same virtual circle.

2. The compact circularly polarized Luneburg lens antenna according to claim 1, characterized in that, Each of the feeders is located on the same plane, the plane where each feeder is located is parallel to the plane where the virtual circle is located, the radiation direction of each feeder is aligned with the central axis position of the Luneburg lens, and the included angle between the radiation directions of any two adjacent feeders is equal.

3. The compact circularly polarized Luneburg lens antenna according to claim 1, wherein, Each of the second air gaps is distributed at the intersection position of each virtual circle and a group of virtual grid arrays; the width and period of the virtual grid array are respectively fixed values.

4. The compact circularly polarized Luneburg lens antenna according to claim 1, wherein The heights of the cylindrical units are equal, and the lengths of the first air gaps in the diameter direction of the virtual circle are not all equal.

5. The compact circularly polarized Luneburg lens antenna according to claim 1, characterized in that, The diameters of the cylindrical units distributed on the same virtual circle are equal, and the diameters of the cylindrical units distributed on the inner virtual circle are larger.

6. The compact circularly polarized Luneburg lens antenna according to claim 1, characterized in that, The feeder includes a waveguide part, a twisting part and a radiation part; the waveguide part is a cuboid, the cross section of the radiation part is the same as the cross section of the waveguide part, and a 45° spatial angle is formed between a symmetry axis of the cross section of the radiation part and a corresponding symmetry axis of the cross section of the waveguide part, and the twisting part connects the waveguide part and the radiation part.

7. The compact circularly polarized Luneburg lens antenna according to claim 6, characterized in that, The waveguide part is provided with a through hole and a blind hole, the through hole is used to connect a coaxial probe, and the blind hole is used to install a coaxial mode converter connector.

8. The compact circularly polarized Luneburg lens antenna according to any one of claims 1-7, characterized in that, The feeder is made of copper, and the cylindrical unit is made of photosensitive resin.

9. The compact circularly polarized Luneburg lens antenna according to any one of claims 1-7, characterized in that, It further includes a connection structure, and the connection structure is used to assemble the Luneburg lens and each feeder so that the Luneburg lens and each feeder maintain a fixed positional relationship with each other.

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