Horn antenna

Abstract

The present application relates to the technical field of communications, and in particular to a horn antenna. The horn antenna comprises a horn cavity and a dielectric protrusion, wherein along the axial direction of the horn cavity, two ends of the horn cavity are respectively a feed input end and a horn opening; and the dielectric protrusion is arranged at the horn opening, the dielectric protrusion and the horn cavity are coaxially arranged, the radial dimension of the dielectric protrusion is less than the diameter of the horn opening, and in the direction from the horn opening to the feed input end, the cross-sectional area of the dielectric protrusion gradually decreases.

Description

Horn antenna

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent application filed on January 9, 2025, with application number 202510037645.0 and entitled "A Horn Antenna", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of antenna technology, and in particular to a horn antenna. Background Technology

[0004] A horn antenna is a common type of radio frequency antenna. The basic structure of a horn antenna is similar to a horn in everyday life. It consists of a small rectangular or circular waveguide segment that gradually expands into a larger opening.

[0005] Gain refers to an antenna's ability to amplify a signal in a specific direction. Since the gain of a horn antenna is primarily determined by its physical dimensions, generally, the larger the horn aperture area, the higher the gain. For applications requiring high gain and narrow beamwidth, horn antennas are often quite large. Summary of the Invention

[0006] Each exemplary embodiment of this application discloses an antenna.

[0007] The embodiments of this application provide the following technical solutions:

[0008] In a first aspect, embodiments of this application provide a horn antenna, which includes a horn cavity and a dielectric protrusion. Along the axial direction of the horn cavity, the two ends of the horn cavity are a feed input terminal and a horn opening, respectively. The dielectric protrusion is disposed at the horn opening and is coaxially arranged with the horn cavity. The radial dimension of the dielectric protrusion is smaller than the diameter of the horn opening, and the cross-sectional area of ​​the dielectric protrusion gradually decreases from the horn opening to the feed input terminal.

[0009] This application incorporates a dielectric protrusion at the horn opening. The radial dimension of the dielectric protrusion is smaller than the diameter of the horn opening, and its cross-sectional area gradually decreases from the horn opening towards the feed input. Electromagnetic waves from the horn opening only partially pass through the dielectric protrusion; this portion of the electromagnetic wave is refracted and focused, while the electromagnetic waves that do not reach the dielectric protrusion propagate along their original path. Therefore, the horn antenna in this application achieves beam shaping by incorporating a dielectric protrusion at the horn opening, thereby improving the horn antenna gain and sidelobe suppression without reducing the main beamwidth.

[0010] In one possible implementation, the dielectric bump is made of a non-magnetic material; and / or, the dielectric bump is made of a dielectric material, and the dielectric constant of the dielectric material is 1.6-2.8.

[0011] In one possible implementation, the medium protrusion is a spherical protrusion.

[0012] In one possible implementation, the medium protrusion is a frustum-shaped protrusion or an elliptical cone-shaped protrusion.

[0013] In one possible implementation, along the axial direction of the horn cavity, the dielectric protrusion includes a first end face and a second end face disposed opposite to each other, wherein the first end face faces the power input terminal, the area ratio of the first end face to the horn opening is 0.22-0.35, and the area ratio of the second end face to the horn opening is 0.4-0.7.

[0014] In one possible implementation, along the axial direction of the horn cavity, the end of the dielectric protrusion near the feed input terminal is designated as the first end. The distance between the first end and the feed input terminal is less than the distance between the horn opening and the feed input terminal, and the axial distance between the first end and the horn opening is less than or equal to 0.125λ1; or, along the axial direction of the horn cavity, the distance between the first end and the feed input terminal is greater than the distance between the horn opening and the feed input terminal, and the axial distance between the first end and the horn opening is less than or equal to 0.25λ1; where λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna in free space.

[0015] In one possible implementation, the horn antenna further includes an end cap that covers the horn opening, and a dielectric protrusion is fixed to the surface of the end cap facing the feed input terminal; and / or, the thickness of the dielectric protrusion is 0.25-0.5λ1, where λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna in free space.

[0016] In one possible implementation, the horn antenna further includes a feed structure and a waveguide. The feed structure includes a cavity, one end of the waveguide is connected to a feed input, and the other end of the waveguide is connected to the cavity. The waveguide is cylindrical in shape, the end face of the cavity connected to the waveguide is an interface face, the interface face is circular in shape, and the end face of the cavity away from the waveguide is a radiating face, the radiating face is elliptical in shape, and the diameter of the circle is the same as the major axis of the ellipse.

[0017] In one possible implementation, the cavity is provided with a horizontally polarized probe and a vertically polarized probe, which are orthogonally arranged to form a feeding structure; and / or, the vertically polarized probe is parallel to the major axis of the ellipse.

[0018] In one possible implementation, the horizontal polarization probe and the vertical polarization probe are located in different planes.

[0019] In one possible implementation, the axial distance L1 between the horizontally polarized probe and the radiating surface, and the axial distance L2 between the vertically polarized probe and the radiating surface are both 0.15-0.50λ2; and / or, the lengths of the horizontally polarized probe and the vertically polarized probe are both 0.15-0.35λ2; where λ2 is the wavelength of the center frequency of the horn antenna.

[0020] In one possible implementation, the major axis of the radiating surface is larger than the length of the vertically polarized probe, and the minor axis of the radiating surface is equal to half the length of the major axis.

[0021] In one possible implementation, the waveguide is detachably connected to the power input.

[0022] In one possible implementation, an annular plate is provided between the waveguide and the feed input terminal, the outer diameter of the annular plate being larger than the diameter of the waveguide; the annular plate is used to connect to the antenna mount.

[0023] In one possible implementation, the outer edge of the annular plate is circular, and the inner edge of the annular plate is circular with a diameter equal to that of the waveguide.

[0024] In one possible implementation, the annular plate is a metal plate. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 is a schematic diagram of the structure of a horn antenna according to an embodiment of this application;

[0027] Figure 2 is a schematic diagram of the structure of a medium protrusion according to an embodiment of this application;

[0028] Figure 3 is a schematic diagram of the structure of the medium protrusion according to another embodiment of this application;

[0029] Figure 4 is a schematic diagram of the structure of a horn antenna according to another embodiment of this application;

[0030] Figure 5 is a partial enlarged view of A shown in Figure 1;

[0031] Figure 6 is a cross-sectional view of BB in Figure 5;

[0032] Figure 7 is an exploded view of a horn antenna according to an embodiment of this application;

[0033] Figure 8 is an exploded view of a horn antenna and antenna mount according to an embodiment of this application;

[0034] Figure 9 is a cross-sectional view of a horn antenna mounted on an antenna bracket according to an embodiment of this application;

[0035] Figure 10 is a horizontal radiation pattern of the horn antenna in Embodiment 1 and Comparative Example 1 of this application;

[0036] Figure 11 is a vertical orientation diagram of the horn antenna of Embodiment 1 and Comparative Example 1 in this application;

[0037] Figure 12 is a graph showing the gain of the horn antenna in Embodiment 1 of this application;

[0038] Figure 13 is a curve showing the gain of the horn antenna in Comparative Example 1 of this application.

[0039] Figure 14 is a graph showing the isolation of the horn antenna in Embodiment 1 of this application;

[0040] Figure 15 is a graph showing the isolation of the horn antenna in Comparative Example 1 of this application.

[0041] Reference numerals: 100-Speaker cavity; 110-Feed input terminal; 120-Speaker opening; 200-Dielectric protrusion; 201-First end; 210-First end face; 220-Second end face; 300-End cap; 400-Feed structure; 410-Cavity; 420-Interface surface; 430-Radiating surface; 440-Horizontal polarization probe; 450-Vertical polarization probe; 500-Waveguide; 600-Ring plate; 610-Ring groove; 700-Connector; 01-Connecting part; 10-Speaker antenna; 20-Antenna mount. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0044] Horn antennas are a common type of radio frequency antenna, and their gain is related to the size of the horn. Generally, the larger the horn aperture area, the higher the gain. Currently, improving the gain and sidelobe suppression of horn antennas mainly relies on increasing the horn aperture. In recent years, metamaterials have also been explored for enhancing the performance of horn antennas. However, metamaterials are complex to fabricate and costly to manufacture, hindering mass production. Moreover, increasing gain requires larger volumes of metamaterials, which not only complicates product integration but also increases the cost of outdoor installation and mounting. Furthermore, conventional metamaterial antenna solutions, while improving antenna gain and sidelobe suppression, also narrow the antenna beamwidth, affecting the coverage area of ​​the equipment. Therefore, how to improve the gain and sidelobe suppression of horn antennas without affecting the main beamwidth and antenna size has become a key research focus in the industry.

[0045] This application provides an antenna, and Figure 1 is a schematic diagram of the structure of a horn antenna according to an embodiment of this application. Referring to Figure 1, the horn antenna 10 includes a horn cavity 100 and a dielectric protrusion 200. Along the axial direction D1 of the horn cavity 100, the two ends of the horn cavity 100 are a feed input terminal 110 and a horn opening 120, respectively. The dielectric protrusion 200 is disposed at the horn opening 120 and is coaxially arranged with the horn cavity 100. The radial dimension of the dielectric protrusion 200 is smaller than the diameter of the horn opening 120. From the horn opening 120 to the feed input terminal 110, the cross-sectional area of ​​the dielectric protrusion 200 gradually decreases.

[0046] This application does not limit the shape and size of the horn cavity 100, but allows for specific design based on actual needs. For example, the horn cavity 100 can be a rectangular horn, a circular horn, a conical horn, an elliptical horn, etc.

[0047] In some possible embodiments, the dielectric protrusion 200 can be made of a non-magnetic material, which is a material that is not easily magnetized. For example, epoxy resin and polytetrafluoroethylene (Teflon) are non-magnetic materials. Optionally, the relative permeability of the non-magnetic material is 1.

[0048] In some possible embodiments, the dielectric protrusion 200 can be made of a dielectric material with a dielectric constant of 1.6-2.8. Specifically, the dielectric constant of the dielectric material can be any other value between 1.6, 1.7, 1.9, 2.1, 2.3, 2.5, 2.7, 2.8, or 1.6-2.8. The axial dimension, i.e., the thickness, of the dielectric protrusion 200 is related to its refractive index; the higher the refractive index, the thinner the dielectric protrusion 200 can be made. Furthermore, materials with dielectric constants within the aforementioned range are relatively easy to obtain and are commonly available.

[0049] For example, the material used to prepare the dielectric protrusion 200 may be polytetrafluoroethylene with a dielectric constant of 2.1, polyethylene with a dielectric constant of 2.3, polystyrene with a dielectric constant of 2.5, or polydicyclopentadiene with a dielectric constant of 2.65.

[0050] The refractive index of the dielectric protrusion 200 is Where ε r Let μ be the dielectric constant of the material with dielectric bump 200. r Let μ be the relative permeability of the material of the dielectric protrusion 200. When the material used to fabricate the dielectric protrusion 200 is a non-magnetic material, μ r =1, and when the dielectric constant of the dielectric protrusion 200 is 1.6-2.8, the refractive index of the dielectric protrusion 200 is between 1.26-1.67. The dielectric protrusion 200 can be made relatively thin, and the materials that can be used to prepare the dielectric protrusion 200 are common materials, resulting in low preparation costs.

[0051] In this application, the shape of the dielectric protrusion 200 is not limited, as long as the radial dimension of the dielectric protrusion 200 is smaller than the diameter of the horn opening 120, and the cross-sectional area of ​​the dielectric protrusion 200 gradually decreases from the horn opening 120 to the power input terminal 110. For example, the dielectric protrusion 200 can be a spherical protrusion, a conical protrusion, a frustum-shaped protrusion, an elliptical conical protrusion, etc.

[0052] Figure 2 is a schematic diagram of the structure of a dielectric protrusion according to an embodiment of this application. Referring to Figures 1 and 2 together, when the dielectric protrusion 200 is shaped like a frustum or an elliptical cone, along the axial direction of the horn cavity 100, the dielectric protrusion 200 includes a first end face 210 and a second end face 220 disposed opposite to each other. The first end face 210 faces the power input terminal 110, and the area ratio of the first end face 210 to the horn opening 120 can be 0.22-0.35. For example, the area ratio of the first end face 210 to the horn opening 120 can be 0.22, 0.24, 0.28, 0.30, 0.32, 0.34, 0.35, or any other value between 0.22 and 0.35. The area ratio of the second end face 220 to the horn opening 120 is 0.4-0.7. For example, the area ratio of the second end face 220 to the horn opening 120 can be 0.40, 0.44, 0.48, 0.50, 0.55, 0.60, 0.70 or any other value between 0.4 and 0.7.

[0053] In this embodiment, the horn antenna 10 controls the dimensions of the first end face 210 and the second end face 220 so that only a portion of the electromagnetic waves at the horn aperture pass through the dielectric protrusion 200. This portion of the electromagnetic waves is refracted upon passing through the dielectric protrusion 200, causing it to focus, while the electromagnetic waves that do not reach the dielectric protrusion 200 propagate along their original path. By adjusting the shape, curvature, and electromagnetic wave illumination area of ​​the dielectric protrusion 200, beam shaping is achieved, thus ensuring that the main beamwidth is not reduced while increasing the gain and sidelobe suppression of the horn antenna 10.

[0054] The shape of the first end face 210 can be circular, elliptical, or polygonal, depending on the actual needs. Similarly, the shape of the second end face 220 can be circular, elliptical, or polygonal, depending on the actual needs.

[0055] In some possible embodiments, when the horn cavity is an elliptical horn, the first end face 210 is elliptical, and the second end face 220 is also elliptical. Optionally, the ratio of the minor axis to the major axis of both the first end face 210 and the second end face 220 is 0.75-0.9. Specifically, the ratio of the minor axis to the major axis can be 0.75, 0.77, 0.79, 0.81, 0.83, 0.85, 0.87, 0.9, or any other value between 0.75 and 0.9.

[0056] Figure 3 is a schematic diagram of the dielectric protrusion structure according to another embodiment of this application. Referring to Figure 3, the dielectric protrusion 200 may be a spherical protrusion. Optionally, the horn antenna 10 further includes a connecting portion 01, which is connected to the end of the dielectric protrusion 200 away from the feed input terminal 110. The connecting portion 01 may match the shape of the end cap of the horn antenna 10 to facilitate connection with the end cap. It is understood that the shape of the connecting portion 01 is not limited in this application and may be set according to actual needs.

[0057] Optionally, the connecting part 01 and the medium protrusion 200 can be an integrally formed structure, or they can be connected by welding, snap-fitting, bonding or other methods.

[0058] Referring to Figures 1 to 3, along the axial direction D1 of the horn cavity 100, the end of the dielectric protrusion 200 near the feed input terminal 110 is designated as the first end 201. The distance between the first end 201 and the feed input terminal 110 is less than the distance between the horn opening 120 and the feed input terminal 110. That is, when the dielectric protrusion 200 extends into the horn cavity 100, the axial distance b between the first end 201 and the horn opening 120 is less than or equal to 0.125λ1. An excessively large axial distance b between the first end 201 and the horn opening 120 will result in a smaller main beamwidth. Here, λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna 10 in free space.

[0059] Figure 4 is a schematic diagram of the structure of a horn antenna according to another embodiment of this application. Referring to Figure 4, along the axial direction D1 of the horn cavity 100, the distance between the first end 201 and the feed input end 110 is greater than the distance between the horn opening 120 and the feed input end 110. That is, the dielectric protrusion 200 is located on the side of the horn opening 120 away from the feed input end 110. Therefore, the axial distance c between the first end 201 and the horn opening 120 is less than or equal to 0.25λ1. An excessively large axial distance c between the first end 201 and the horn opening 120 will result in a smaller main beamwidth. Here, λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna 10 in free space.

[0060] It should be noted that when the medium protrusion 200 is a frustum-shaped protrusion or an elliptical cone-shaped protrusion, as shown in Figures 1, 2 and 4, the first end 201 is the first end face 210; when the medium protrusion 200 is a spherical protrusion, as shown in Figure 3, the first end 201 is the vertex of the spherical protrusion, that is, the highest point of the spherical protrusion.

[0061] Referring again to Figures 1 and 4, along the axial direction D1 of the horn cavity 100, the thickness h of the dielectric protrusion 200 is 0.25-0.5λ1, where λ1 is the wavelength of the electromagnetic wave transmitted and received by the horn antenna in free space. For example, the thickness h of the dielectric protrusion 200 can be any other value among 0.25λ1, 0.26λ1, 0.28λ1, 0.30λ1, 0.35λ1, 0.35λ1, 0.40λ1, 0.45λ1, 0.5λ1, or 0.25-0.5λ1.

[0062] Figure 5 is a partial enlarged view of A shown in Figure 1, and Figure 6 is a cross-sectional view of BB in Figure 5. Referring to Figures 5 and 6, the horn antenna 10 also includes a feed structure 400 and a waveguide 500. The feed structure 400 includes a cavity 410. One end of the waveguide 500 is connected to the feed input terminal 110, and the other end of the waveguide 500 is connected to the cavity 410.

[0063] In some possible embodiments, the waveguide 500 is cylindrical, the end face of the cavity 410 connected to the waveguide 500 is an interface surface 420, the interface surface 420 is circular, the end face of the cavity 410 away from the waveguide 500 is a radiating surface 430, the radiating surface 430 is elliptical, and the diameter D of the circle is the same as the major axis S of the ellipse.

[0064] In some possible embodiments, the cavity 410 is provided with a horizontally polarized probe 440 and a vertically polarized probe 450, which are orthogonally arranged to form a feeding structure, that is, the horizontally polarized probe 440 and the vertically polarized probe 450 are perpendicular to each other.

[0065] In some possible embodiments, the vertically polarized probe 450 is parallel to the long axis of the radiating surface 430.

[0066] As shown in Figure 6, the dimension of the major axis of the radiating surface 430 is greater than the length of the vertical polarization probe 450.

[0067] In some possible embodiments, the size of the minor axis of the radiating surface 430 is equal to half the size of the major axis to obtain a preset resonant frequency.

[0068] In this application, an elliptical conical cavity 400 is used as the feed structure 410, forming an elliptical waveguide. Compared to common circular and rectangular waveguides, the elliptical waveguide has lower conductor attenuation loss and does not exhibit polarization degeneracy. The cutoff wavelength of the elliptical waveguide is calculated using the following formula:

[0069] Where, λ c The cutoff wavelength is the smallest wavelength at which a waveguide can support the propagation of a specific mode. 'a' refers to the semi-major axis of the elliptical waveguide, which is half the major axis of the elliptical cross-section. π is pi, approximately 3.14159. 'e' is the eccentricity of the ellipse, a parameter describing the shape of the ellipse, defined as the ratio of the focal length to the semi-major axis, i.e., e = c / a, where c is the distance from the center to the focal point. 'q' represents the eigenvalue of the propagation mode in the waveguide, which is related to the mode type. In the case of an elliptical waveguide, 'q' may be related to the order of the TE (transverse electromagnetic wave) or TM (transverse magnetic wave) mode.

[0070] According to the above formula and in conjunction with Figure 6, once the required operating frequency of the horn antenna 10 is determined, the major axis a and the eccentricity e of its ellipse can be determined, thereby determining the structure of the elliptical cavity 410. The horizontally and vertically polarized coaxial waveguides have different feed lengths. The horizontally polarized probe 440 is parallel to the minor axis of the elliptical cavity 410, thus horizontal polarization excites both a transverse electric o-mode (m=1, n=1, TEo11 mode) and a transverse magnetic o-mode (m=1, n=1, TMe11 mode). The vertically polarized probe 450 is parallel to the major axis of the elliptical cavity 410, thus vertical polarization excites both a transverse electric o-mode (m=1, n=1, TEe11 mode) and a transverse magnetic o-mode (m=1, n=1, TMe11 mode). By exciting different modes through horizontal and vertical polarization, port coupling can be reduced.

[0071] In this model, "TE" and "TM" represent the transverse electric mode and transverse magnetic mode, respectively. The "transverse electric" mode means the electric field vector is transverse in the direction of propagation, while the "transverse magnetic" mode means the magnetic field vector is transverse in the direction of propagation. The letters "o" and "e" are typically used to distinguish different field distribution modes, where "o" represents even symmetry and "e" represents even symmetry. The numbers "m" and "n" are mode indices, representing the half-wavenumbers of the field distribution along the major and minor axes of the elliptical cavity, respectively. In these modes, "m=1, n=1" indicates a variation of one half-wavelength along both the major and minor axes.

[0072] In some possible embodiments, the horizontal polarization probe 440 and the vertical polarization probe 450 are located in different planes, that is, the horizontal polarization probe 440 and the vertical polarization probe 450 are offset by being out of plane, which can increase the spacing between the horizontal polarization probe 440 and the vertical polarization probe 450, thereby reducing the port isolation of the horn antenna 10. Compared with the circular or square common normal coplanar feeding structure, the isolation of the horn antenna 10 with the above structure is improved by more than 13 dB.

[0073] In some possible embodiments, the axial distance L1 between the horizontal polarization probe 440 and the radiating surface 430, and the axial distance L2 between the vertical polarization probe 450 and the radiating surface 430 are both 0.15-0.50λ2, where λ2 is the wavelength of the center frequency of the horn antenna 10. Setting L1 and L2 within the above range ensures that the frequency of the horn antenna 10 is within a suitable range, neither too high nor too low.

[0074] It is understandable that L1 can be less than L2 or greater than L2, depending on the actual needs.

[0075] In some possible embodiments, the length L3 of the horizontal polarization probe 440 and the length L4 of the vertical polarization probe 450 are both 0.15-0.35λ2, where λ2 is the wavelength of the center frequency of the horn antenna 10. Setting L3 and L4 within the above range ensures that the frequency of the horn antenna 10 is within a suitable range, neither too high nor too low.

[0076] Figure 7 is an exploded view of a horn antenna according to an embodiment of this application. Referring to Figure 7, the horn antenna 10 also includes an end cap 300, which covers the horn opening 120 to prevent foreign objects from entering the horn cavity 100, thereby improving the cleanliness and service life of the horn antenna 10.

[0077] In some possible embodiments, the dielectric protrusion 200 is fixed to the surface of the end cap 300 facing the feed input terminal 110. The surface of the end cap 300 facing the horn cavity 100 has a recess, and the end of the dielectric protrusion 200 away from the feed input terminal 110 extends into the recess. Alternatively, when the horn antenna 10 also includes a connecting portion 01, the connecting portion 01 extends into the recess. This not only better secures the dielectric protrusion 200 and the end cap 300, but also facilitates adjustment of the distance between the first end 201 of the dielectric protrusion 200 and the feed input terminal 110, preventing the dielectric protrusion 200 from extending excessively into the horn cavity 100, thereby better refracting electromagnetic waves from the horn aperture.

[0078] Figure 8 is an exploded view of a horn antenna and antenna mount according to an embodiment of this application, and Figure 9 is a cross-sectional view of a horn antenna installed on an antenna mount according to an embodiment of this application. Referring to Figures 8 and 9, the dielectric protrusion 200 and the end cap 300 are connected by a connector 700, which can be a screw or bolt, etc., to facilitate the disassembly and assembly of the dielectric protrusion 200 and the end cap 300.

[0079] Referring again to Figures 8 and 9, the waveguide 500 is detachably connected to the power input terminal 110. Specifically, the two can be fixed by clips, bolts, or screws, which facilitates the assembly and disassembly of the waveguide 500 and the horn cavity 100, enabling different models of horn cavities 100 to share the same feed structure 400.

[0080] In some possible embodiments, an annular plate 600 is provided between the waveguide 500 and the power input terminal 110 of the horn cavity 100. The outer diameter of the annular plate 600 is larger than the diameter of the waveguide 500, that is, the annular plate 600 extends radially away from the connection with the waveguide 500.

[0081] It is understood that this application does not limit the specific shape of the annular plate 600. The outer edge of the annular plate 600 can be circular, square, or other shapes. As shown in Figure 8, the outer edge of the annular plate 600 is circular, and the inner edge of the annular plate 600 is circular with a diameter equal to the diameter of the waveguide 500.

[0082] In some possible embodiments, the annular plate 600 forms an annular groove 610 on its surface facing the horn cavity 100. The feed input terminal 110 of the horn cavity 100 extends into the annular groove 610 and is fixedly connected to the inner wall of the annular groove 610 by bolts, screws, etc. The annular plate 600 facilitates the connection between the horn cavity 100 and the antenna mount 20.

[0083] In some possible embodiments, the annular plate 600 is a metal plate, which reduces the back radiation of the horn antenna 10 and further improves the front-to-back ratio of the horn antenna 10. The front-to-back ratio refers to the ratio of the power flux density in the maximum radiation direction of the antenna main lobe (e.g., 0°) to the maximum power flux density in the opposite direction (e.g., within the range of 180°±20°).

[0084] The horn antenna in this application will be described below with reference to specific embodiments and comparative examples.

[0085] Example 1

[0086] Embodiment 1 of this application is a horn antenna. Referring to Figure 1, the horn opening 120 of the horn antenna 10 can be elliptical, with a major axis of 244 mm and a minor axis of 202 mm. A dielectric protrusion 200 is provided at the horn opening 120. The dielectric protrusion 200 is made of polytetrafluoroethylene and has an elliptical cone shape. Along the axial direction of the horn cavity 100, the dielectric protrusion 200 includes a first end face 210 and a second end face 220 disposed opposite to each other. The first end face 210 faces the feed input terminal 110 and is elliptical, with a major axis of 130 mm and a minor axis of 108 mm. The area ratio of the first end face 210 to the horn opening 120 is 0.28. The second end face 220 is also elliptical, with a major axis of 180 mm and a minor axis of 150 mm. The area ratio of the second end face 220 to the horn opening 120 is 0.56. The thickness of the dielectric protrusion 200 is 20 mm.

[0087] Referring to Figures 5 and 6, the horn antenna 10 also includes a cylindrical waveguide 500 and an elliptical conical feed structure 400 cavity 410. The waveguide 500 is located between the horn cavity 100 and the feed structure 400 cavity 410. The end face of the cavity 410 connected to the waveguide 500 is an interface surface 420, which is circular with a diameter of 44 mm. The end face of the cavity 410 away from the waveguide 500 is a radiating surface 430, which is elliptical with a major axis of 44 mm and a minor axis of 22 mm. A horizontally polarized probe 440 and a vertically polarized probe 450 are disposed within the cavity 410. The horizontally polarized probe 440 and the vertically polarized probe 450 orthogonally form a feed structure, and their centerlines coincide, but they are located in different planes. The axial distance L1 between the horizontal polarization probe 440 and the radiation surface 430, and the axial distance L2 between the vertical polarization probe 450 and the radiation surface 430 are both 11.5 mm. The length L3 of the horizontal polarization probe 440 and the length L4 of the vertical polarization probe 450 are both 10 mm.

[0088] Comparative Example 1

[0089] Comparative Example 1 is a horn antenna. The specific structure can be referred to as the horn antenna 10 in Example 1. The difference is that the horn antenna in Comparative Example 1 does not have a dielectric protrusion 200, and the shape of the feed structure cavity is cylindrical.

[0090] The wireless signal strength of the horn antennas in Example 1 and Comparative Example 1 was tested.

[0091] Figure 10 is a horizontal radiation pattern of the horn antennas of Embodiment 1 and Comparative Example 1 in this application. Figure 11 is a vertical radiation pattern of the horn antennas of Embodiment 1 and Comparative Example 1 in this application. Referring to Figures 10 and 11, the circumference represents the angle, and the vertical axis represents the gain value. Within the main beam range of 20°, the main beam coverage of the horn antenna 10 in Embodiment 1 and the horn antenna in Comparative Example 1 overlaps, and the gain of the horn antenna 10 in Embodiment 1 is higher than that of the horn antenna in Comparative Example 1. However, outside the main beam range (20°), the gain of the horn antenna 10 in Embodiment 1 fades rapidly, and its sidelobe suppression is better than that of the horn antenna in Comparative Example 1. As shown in Figure 10, the sidelobe suppression of the horn antenna 10 in Example 1 is improved by more than 8dB compared with that of the horn antenna in Comparative Example 1 (m1-m2=1.4799-(-8.6333)=10.1132, m3-m4=1.4667-(-7.4956)=8.9623). Therefore, the horn antenna 10 in Example 1 achieves high sidelobe suppression characteristics.

[0092] Figure 12 is a gain curve of the horn antenna in Embodiment 1 of this application, and Figure 13 is a gain curve of the horn antenna in Comparative Example 1 of this application. Referring to Figures 12 and 13, the gain value of the horn antenna 10 at its maximum gain point m2 in Embodiment 1 is 22.0441 dB. The gain value of the horn antenna at its maximum gain point m1 in Comparative Example 1 is 19.6339 dB. Therefore, the gain of the horn antenna 10 in Embodiment 1 is increased by 2.4 dB compared to that of the horn antenna in Comparative Example 1.

[0093] Figure 14 is a graph of the isolation of the horn antenna in Embodiment 1 of this application. Referring to Figure 14, the starting point of the operating frequency of the horn antenna 10 in Embodiment 1 is marked point 1 in Figure 14, the ending point of the operating frequency is marked point 2 in Figure 14, and the maximum value between marked point 1 and marked point 2 is marked point 5. Therefore, the isolation of the horn antenna 10 is 27.31 dB.

[0094] Figure 15 is a graph showing the isolation of the horn antenna 10 in Comparative Example 1 of this application. Referring to Figure 15, the starting point of the operating frequency of the horn antenna in Comparative Example 1 is marked point 1 in Figure 14, the ending point of the operating frequency is marked point 2 in Figure 14, and the maximum value between marked point 1 and marked point 2 is marked point 3. Therefore, the isolation of the horn antenna in Comparative Example 1 is 14.09 dB. Thus, the isolation of the horn antenna 10 in Example 1 is improved by 13.22 dB compared to that of the horn antenna in Comparative Example 1.

[0095] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A horn antenna, comprising: A horn cavity, with a power input terminal and a horn opening at its two ends along the axial direction of the horn cavity; A dielectric protrusion is provided at the horn opening and is coaxially arranged with the horn cavity. The radial dimension of the dielectric protrusion is smaller than the diameter of the horn opening, and the cross-sectional area of ​​the dielectric protrusion gradually decreases from the horn opening to the power input terminal.

2. The horn antenna according to claim 1, wherein, The material of the dielectric protrusion is a non-magnetic material; and / or, The dielectric protrusion is made of a dielectric material, and the dielectric constant of the dielectric material is 1.6-2.

8.

3. The horn antenna according to claim 2, wherein, The medium protrusion is a spherical protrusion.

4. The horn antenna according to claim 2, wherein, The medium protrusion is a frustum-shaped protrusion or an elliptical cone-shaped protrusion.

5. The horn antenna according to claim 4, wherein, Along the axial direction of the horn cavity, the dielectric protrusion includes a first end face and a second end face disposed opposite to each other, wherein the first end face faces the power input terminal, the area ratio of the first end face to the horn opening is 0.22-0.35, and the area ratio of the second end face to the horn opening is 0.4-0.

7.

6. The horn antenna according to any one of claims 1-5, wherein, Along the axial direction of the horn cavity, with the end of the dielectric protrusion near the feed input terminal as the first end, and the distance between the first end and the feed input terminal being less than the distance between the horn opening and the feed input terminal, the axial distance between the first end and the horn opening is less than or equal to 0.125λ1; where λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna in free space.

7. The horn antenna according to any one of claims 1-5, wherein, If the distance between the first end and the power input terminal is greater than the distance between the horn opening and the power input terminal along the axial direction of the horn cavity, then the axial distance between the first end and the horn opening is less than or equal to 0.25λ1. Wherein, λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna in free space.

8. The horn antenna according to any one of claims 1-5, wherein, The horn antenna further includes an end cap that covers the horn opening, and the dielectric protrusion is fixed to the surface of the end cap facing the feed input terminal; and / or, The thickness of the dielectric protrusion is 0.25-0.5λ1, where λ1 is the wavelength of the electromagnetic waves transmitted and received by the horn antenna in free space.

9. The horn antenna according to any one of claims 1-5, wherein, The horn antenna further includes a feed structure and a waveguide. The feed structure includes a cavity. One end of the waveguide is connected to the feed input terminal, and the other end of the waveguide is connected to the cavity. The waveguide is cylindrical in shape. The end face of the cavity connected to the waveguide is an interface face, which is circular in shape. The end face of the cavity away from the waveguide is a radiating face, which is elliptical in shape, and the diameter of the circle is the same as the major axis of the ellipse.

10. The horn antenna according to claim 9, wherein, The cavity is equipped with a horizontally polarized probe and a vertically polarized probe, which are orthogonally arranged to form a feeding structure. The vertically polarized probe is parallel to the long axis of the radiating surface.

11. The horn antenna according to claim 10, wherein, The horizontal polarization probe and the vertical polarization probe are located in different planes.

12. The horn antenna according to claim 10 or 11, wherein, The axial distance L1 between the horizontally polarized probe and the radiation surface, and the axial distance L2 between the vertically polarized probe and the radiation surface, are both 0.15-0.50λ2, and / or, The lengths of both the horizontally polarized probe and the vertically polarized probe are 0.15-0.35λ². Wherein, λ2 is the wavelength of the center frequency of the horn antenna.

13. The horn antenna according to claim 10, wherein, The major axis of the radiating surface is larger than the length of the vertically polarized probe; and / or, The minor axis of the radiating surface is equal to half the major axis.

14. The horn antenna according to claim 9, wherein, The waveguide is detachably connected to the power input terminal.

15. The horn antenna according to claim 14, wherein, An annular plate is provided between the waveguide and the power input terminal, and the outer diameter of the annular plate is larger than the diameter of the waveguide.

16. The horn antenna according to claim 15, wherein, The annular plate is used to connect to the antenna mount.

17. The horn antenna according to claim 14, wherein, The outer edge of the annular plate is circular, and the inner edge of the annular plate is circular with a diameter equal to that of the waveguide.

18. The horn antenna according to claim 14, wherein, The annular plate is a metal plate.

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