Low-scattering antenna

Abstract

The invention discloses a monopole antenna with a low scattering characteristic. The monopole antenna comprises a metasurface reflecting plate and a monopole antenna body arranged above the metasurface reflecting plate. The monopole antenna and the metasurface reflecting plate are arranged at intervals, and the plane where the monopole antenna is located is perpendicular to the plane where the metasurface reflecting plate is located. The technical scheme that a complete metal floor is generally adopted as an antenna reflecting surface in a traditional scheme is replaced by the reflecting plate with the metasurface, and compared with an antenna with a complete metal surface, the periodic structure of the metasurface can effectively reduce reflection and scattering of electromagnetic waves, and meanwhile the radiation performance of the antenna is hardly affected. The technical problem of compatible regulation and control of the radiation performance and the low scattering performance of the antenna is solved, and the contradiction between the electrical performance and the low scattering performance is solved.

Description

Technical Field

[0001] This application relates to antenna technology, and more specifically, to a monopole antenna with low scattering characteristics. Background Technology

[0002] With the development of modern wireless communication, radar, and low-scattering technologies, broadband low-scattering antennas are increasingly widely used. Developing antennas that simultaneously possess broadband and low-scattering characteristics has become a hot topic and a challenging problem this year. Low-scattering antennas need to ensure that their radiation characteristics, such as antenna gain and radiation pattern, are not affected; on the other hand, they must also consider the overall low RCS (radar cross section) performance of the antenna to ensure the safety of military equipment. Scattering sources include specular reflection from the antenna reflector, edge diffraction from the antenna shape, and diffraction from the antenna's apex. Therefore, it is necessary to optimize the far-field radiation performance of the antenna selection while simultaneously designing low-scattering antennas to achieve low-scattering performance.

[0003] Antennas with low scattering characteristics offer several advantages. In military and aerospace applications, low scattering improves signal quality in communication and radar systems, reduces electromagnetic wave reflection and scattering, and decreases device detectability. In civilian applications, antennas with low scattering characteristics simultaneously improve communication quality, enhance anti-interference capabilities, and mitigate environmental interference. Current techniques for reducing antenna RCS primarily utilize high-impedance surfaces, frequency-selective surfaces, conformal antenna design, or slots in the antenna structure to disrupt coupled radiation modes caused by external electric fields.

[0004] Low-scatter antennas can reduce the scattering signature of communication, radar, IFF (Identification Friend or Foe) signals, and RCS (Radar Cross Section), thereby increasing the stealth of friendly aircraft. Low-scatter antennas not only do not affect the antenna's radiation performance, but also include control over antenna scattering and reduction of the radar cross section at multiple incident angles.

[0005] In existing technologies, to achieve low scattering performance, a complete metal ground plane is usually used as the antenna reflector. By reducing the antenna's back radiation, the forward gain of the monopole antenna is improved. Although the traditional solution can improve the antenna gain, the all-metal reflector usually results in a large RCS value. Summary of the Invention

[0006] The solution to the above problems in this application is as follows: a monopole antenna with low scattering characteristics is provided, including a metasurface reflector and a monopole antenna disposed above the metasurface reflector; the monopole antenna and the metasurface reflector are spaced apart, and the plane of the monopole antenna is perpendicular to the plane of the metasurface reflector.

[0007] Preferably, the monopole antenna is placed along the side length or diagonal direction of the metasurface reflector.

[0008] Preferably, the monopole antenna includes a dielectric substrate, one surface of which is provided with a radiator connected to one side of the dielectric substrate via a feed line; the other surface of the dielectric substrate is provided with a ground plane.

[0009] Preferably, the radiator is a circular metal sheet.

[0010] Preferably, the feed line includes a second feed line close to the radiator and a first feed line far from the radiator, the first feed line and the second feed line are electrically connected, and the second feed line is shorter and wider than the first feed line.

[0011] Preferably, the floor is a semi-elliptical metal sheet.

[0012] Preferably, the surface of the metasurface reflector near the monopole antenna is provided with metasurface units arranged in a checkerboard pattern.

[0013] Preferably, the metasurface unit includes a regular polygonal frame, with a notch bent from the middle of each side of the regular polygonal frame toward the center; within the regular polygonal frame, fractal blocks are provided between adjacent notches.

[0014] Preferably, the metasurface unit includes a square outer frame, and the middle section of each side of the regular polygonal outer frame is bent towards the center to form a notch; within the square outer frame, fractal blocks are arranged between adjacent notches.

[0015] Preferably, the notch is an isosceles triangle structure; the fractal block is a kite-shaped structure.

[0016] The implementation of the present invention has the following beneficial effects: This application uses a metasurface as a reflector. The periodic structure of the metasurface can effectively reduce the reflection and scattering of electromagnetic waves, while hardly affecting the radiation performance of the antenna. Using a metasurface reflector can solve the technical problem of compatible control of antenna radiation performance and low scattering performance, and resolve the contradiction between electrical performance and low scattering performance. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a preferred embodiment of the low-scattering antenna of this application; Figure 2This is a schematic diagram of a monopole antenna for the low-scattering antenna of this application; Figure 3 This is a schematic diagram of the metasurface reflector of the low-scattering antenna of this application; Figure 4 This is a schematic diagram of the metasurface unit structure of the metasurface reflector of the low-scattering antenna of this application; Figure 5 The reflection coefficient curve of the low-scattering antenna of this application; Figure 6 This is a schematic diagram comparing the gain curves of the proposed solution and the metal reflector solution. Figure 7 This is a schematic diagram comparing the scattering curves of the proposed solution and the metal reflector solution. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] like Figure 1 The diagram shown is a schematic representation of a low-scattering antenna structure according to a preferred embodiment of the present invention. In this embodiment, the low-scattering monopole antenna includes a metasurface reflector 100 and a monopole antenna 200 disposed above the metasurface reflector 100; the monopole antenna 200 and the metasurface reflector 100 are spaced apart, and the plane of the monopole antenna is perpendicular to the plane of the metasurface reflector.

[0023] In this embodiment, both the monopole antenna 200 and the metasurface reflector 100 are plate-shaped structures. The monopole antenna 200 is placed perpendicularly to the metasurface reflector 100 and 1-3 mm above the center; in this embodiment, the distance is 2 mm. The azimuth angle of the monopole antenna 200 can be along the side length of the metasurface reflector 100 or along the diagonal of the metasurface reflector 100 (i.e., the plane containing the monopole antenna 200 is parallel to the metasurface reflector 100 or its diagonal). For example, in this embodiment… Figure 1 The antenna shown is positioned along its side length. With this orientation, the antenna's impedance matching performance is as follows: Figure 5 As shown, this indicates good matching within this frequency band. The designed metasurface exhibits excellent reflection within the 2-2.5 GHz range, compared to an all-metal reflector. Figure 6 As shown, using a metasurface reflector as a frequency selective metasurface (FSS) has a relatively small impact on gain and antenna radiation pattern. Figure 7 The image shows the radar cross section when electromagnetic waves are incident perpendicularly. This example demonstrates that the frequency-selective metasurface used as a reflector can significantly reduce the RCS value compared to an all-metal reflector, and can also reduce the RCS value when incident at other angles.

[0024] In this embodiment, the surface of the metasurface reflector 100 near the monopole antenna 200 is provided with a metasurface unit arranged in a checkerboard pattern of M×N. This metasurface unit makes the metasurface reflector 100 form a frequency selective surface, which has the effect of a band-stop filter. Moreover, as a reflector, it can significantly reduce the RCS value compared with an all-metal reflector.

[0025] like Figure 2The diagram shows a schematic representation of an embodiment of the monopole antenna 200 of the low-scattering antenna of this application. The monopole antenna 200 includes a dielectric substrate 201. A radiator 202 is disposed on one surface of the dielectric substrate 201. The radiator 202 is connected to one side of the dielectric substrate 201 via feed lines. In this embodiment, the feed lines include a second feed line 203 near the radiator 202 and a first feed line 204 away from the radiator 202. The second feed line 203 is shorter and wider than the first feed line 204, forming a two-stage feed line structure. Using this two-stage feed line structure, the first feed line 204 can use a standard impedance, such as 50Ω, to achieve impedance matching with the RF source. The second feed line 203 is shortened and widened to achieve a lower impedance, enabling impedance matching with the radiator 202. The two-stage feed line structure achieves impedance transformation. A ground plane 205 is disposed on the other surface of the dielectric substrate 201 near the feed line. In this embodiment, the radiator 202 is a circular metal sheet, and the ground plane 205 is a semi-elliptical metal sheet. In a feasible example, the parameters of the monopole antenna 202 are as follows: the dielectric substrate 201 has a relative permittivity of 3.55 and a thickness of 1 mm. The first feed line 204 is 16 mm long and 1.5 mm wide, and the second feed line 203 is 1.5 mm long and 2.5 mm wide. The radiator 202 has a diameter of 24 mm. The semi-elliptical ground plane 205 has a semi-major axis of 20 mm and a semi-minor axis of 15 mm.

[0026] like Figure 3 This diagram illustrates a structural schematic of one embodiment of the metasurface reflector 100 of this application. The metasurface reflector 100 is formed by a disk-shaped distribution of periodic metal units, creating a metasurface. The metasurface utilizes a periodic structure to form a frequency-selective surface, effectively acting as a band-stop filter. In this embodiment, the metasurface comprises 7×7 checkerboard-shaped metasurface units, with a spacing of 22.4 mm between adjacent units. This example design is capable of blocking electromagnetic waves in the 2~2.5 GHz range, thus achieving the effect of a metallic reflective surface.

[0027] In this application, the metasurface unit adopts a second-order fractal of a regular polygon, such as... Figure 4The diagram shows the structure of a metasurface unit 101 in this embodiment. The metasurface unit 101 includes a square outer frame 1011. Each side of the square outer frame has an isosceles triangular notch 1012 bent towards the center, forming an approximately four-petaled snowflake shape. The metasurface unit 101 also includes multiple fractal blocks 1013, located within each snowflake petal. The fractal blocks 1013 exhibit self-similarity with their corresponding snowflake petals; for example, in this embodiment, the fractal block 1013 has a kite-like structure. In this embodiment, the parameters of the metasurface unit 101 are: a square outer frame with a side length of 20.4 mm and a metal line width of 0.6 mm; the isosceles triangular notch 1012 has a width of 6.8 mm, a height of 8.8 mm, and two metal lines with a width of 0.8 mm. Each unit is printed on a 1 mm thick dielectric substrate with a relative permittivity of 3.66. The unit size is 20.4 × 20.4 mm. The kite-shaped fractal block has one set of short sides measuring 2 mm and one set of long sides measuring 7.2 mm.

[0028] The metasurface unit given in this embodiment is a second-order fractal of a square frame. However, this invention is not limited to this. For example, the frame can be hexagonal. An isosceles triangle notch is bent from the middle of each side of the hexagon toward the center to form a six-petal snowflake. Fractal blocks are set between adjacent notches, that is, between each snowflake petal. The hexagonal metasurface units can be arranged in a checkerboard pattern or in a dense arrangement.

[0029] Based on the requirement of compatibility between antenna radiation performance and low scattering performance, this invention obtains a periodic equivalent circuit through reverse design, and then obtains a second-order fractal structure of regular polygon.

[0030] The antennas using the embodiments of the present invention replace the traditional approach of using a complete metal ground plane as the antenna reflector with a metasurface reflector. Compared with antennas with a complete metal surface, the periodic structure of the metasurface can effectively reduce the reflection and scattering of electromagnetic waves, while having almost no impact on the antenna's radiation performance. The low-scattering antenna proposed in this invention can solve the technical challenge of compatible control of antenna radiation performance and low-scattering performance, resolving the contradiction between electrical performance and low-scattering performance. It will enable the balanced design of electrical performance and low-scattering performance for special-function antennas. The product will be applied in advanced aerospace equipment, and its technology can be widely used in aerospace, rail transportation, and defense industries. It is of great significance to the development of metamaterials and low-scattering technology, possessing significant technical value and broad market prospects.

[0031] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0032] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-scattering antenna, characterized in that, It includes a metasurface reflector (100) and a monopole antenna (200) disposed above the metasurface reflector (100); the monopole antenna (200) is disposed at a distance from the metasurface reflector (100), and the plane of the monopole antenna (200) is perpendicular to the plane of the metasurface reflector (100).

2. The low-scattering antenna according to claim 1, characterized in that, The monopole antenna (200) is placed along the side length direction or diagonal direction of the metasurface reflector (100).

3. The low-scattering antenna according to claim 1, characterized in that, The monopole antenna (200) includes a dielectric substrate (201), one surface of which is provided with a radiator (202), the radiator (202) being connected to one side of the dielectric substrate (201) via a feed line; the other surface of the dielectric substrate (201) is provided with a ground plane (205).

4. The low-scattering antenna according to claim 3, characterized in that, The radiator (202) is a circular metal sheet.

5. The low-scattering antenna according to claim 3, characterized in that, The feed line includes a second feed line (203) close to the radiator (202) and a first feed line (204) away from the radiator (202). The first feed line (203) and the second feed line (204) are electrically connected. The second feed line (204) is shorter in length and wider than the first feed line (203).

6. The low-scattering antenna according to claim 3, characterized in that, The floor (205) is a semi-elliptical metal sheet.

7. The low-scattering antenna according to claim 1, characterized in that, The surface of the metasurface reflector (100) near the monopole antenna (200) is provided with metasurface units (101) arranged in a checkerboard pattern.

8. The low-scattering antenna according to claim 7, characterized in that, The metasurface unit (101) includes a regular polygonal frame, with a notch bent from the middle of each side of the regular polygonal frame toward the center; within the regular polygonal frame, fractal blocks are arranged between adjacent notches.

9. The low-scattering antenna according to claim 8, characterized in that, The metasurface unit (101) includes a square outer frame (1011), and the middle section of each side of the regular polygonal outer frame (1011) is bent towards the center to form a notch (1012); within the square outer frame (1011), fractal blocks (1013) are arranged between adjacent notches.

10. The low-scattering antenna according to claim 9, characterized in that, The notch (1012) is an isosceles triangle structure; the fractal block (1013) is a kite-shaped structure.

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