Low-profile vertical polarization waveguide antenna structure

Abstract

The invention provides a low-profile vertical polarization waveguide antenna structure, which comprises a waveguide antenna, and is characterized in that the waveguide antenna comprises a radiation cavity, a radiation slot and a waveguide feeder line, the waveguide feed line extends from the middle position of the radiation cavity in a manner of deviating from the radiation cavity so as to form T-shaped arrangement with the radiation cavity, and the waveguide feed line is short-circuited at the tail end close to the radiation cavity; and the two radiation slots are located above the radiation cavity and are respectively arranged at the inner sides of the two tail ends of the radiation cavity, and the radiation slots are communicated with the radiation cavity and penetrate through the top plane of the antenna structure.

Description

Technical Field

[0001] This invention relates to antenna structures adapted to low-altitude environments, and more particularly to a low-profile vertically polarized waveguide antenna structure. Background Technology

[0002] Existing antenna structures for low-altitude environments typically employ microstrip antennas, which have low radiation efficiency. Even when waveguide antennas are used, accurate vertical polarization is often impossible due to layout constraints, thus failing to meet the requirements of certain scenarios, such as the need for low-altitude aircraft to reduce signal attenuation caused by ground reflections and adapt to omnidirectional communication requirements in low-altitude environments. Furthermore, these antennas usually have a high profile, making them unsuitable for small-size deployments. Summary of the Invention

[0003] In view of the above problems, the present invention provides a low-profile vertically polarized waveguide antenna structure, including a waveguide antenna comprising: a radiating cavity, radiating slots, and a waveguide feed line, wherein the two ends of the radiating cavity are closed and short-circuited, the waveguide feed line extends from the middle of the radiating cavity away from the radiating cavity and is arranged in a T-shape with the radiating cavity, the waveguide feed line is short-circuited at the end near the radiating cavity, there are two radiating slots, the two radiating slots are located above the radiating cavity and are respectively disposed inside the two ends of the radiating cavity, the radiating slots connect to the radiating cavity and penetrate the top plane of the antenna structure.

[0004] According to one aspect of the invention, the top surface of the radiating cavity is flush with the top surface of the waveguide feed line, and the height of the radiating cavity is half the height of the waveguide feed line.

[0005] According to one aspect of the present invention, a matching body is provided below the radiation cavity, the matching body being in the form of an inclined surface.

[0006] According to one aspect of the invention, a power divider is provided between the radiation gaps, the power divider extending into the radiation cavity and dividing the radiation cavity into two radiation regions.

[0007] According to one aspect of the invention, the radiating cavity is an H-plane waveguide cavity, and the waveguide feed line is an E-plane waveguide transmission line.

[0008] According to one aspect of the invention, a beam-constraining structure is provided above the radiation slit, the beam-constraining structure resembling a horn or a stepped structure facing the radiation direction.

[0009] According to one aspect of the invention, the length ratio of the long side to the wide side of the waveguide feed line is close to 2:1 and meets the cutoff requirement of the TE10 mode at the operating frequency; the length ratio of the long side to the wide side of the radiation cavity is close to 2:1 and meets the cutoff requirement of the TE10 mode at the operating frequency.

[0010] According to one aspect of the invention, the length of the radiation slit is half the operating wavelength, and the spacing of the radiation slits is approximately half the operating wavelength.

[0011] According to one aspect of the present invention, the waveguide antenna structure is made of metal or non-metallic materials such as plastic and then subjected to surface metallization treatment.

[0012] According to one aspect of the present invention, the waveguide antenna structure includes a plurality of waveguide antennas, which are formed by multi-stage parallel branching through a centimeter network at one end of the waveguide feed line connected to the radiating cavity. Attached Figure Description

[0013] Figure 1 A top view of the vertically polarized waveguide antenna structure according to the present invention is shown; Figure 2 A structural diagram of the waveguide antenna in the vertically polarized waveguide antenna structure according to the present invention is shown; Figure 3 The vertically polarized waveguide antenna structure according to the present invention is shown along... Figure 1 The sectional view obtained by the cutting line AA in the middle; Figure 4 The vertically polarized waveguide antenna structure according to the present invention is shown along... Figure 1 The sectional view obtained by the cutting line BB in the middle; Figure 5 A perspective view of a vertically polarized waveguide antenna structure according to the present invention is shown; Figure 6 A perspective view of an embodiment of a vertically polarized waveguide antenna structure with a beam constraint structure according to the present invention is shown; Figure 7 A perspective view of a two-stage parallel four-slot vertically polarized waveguide antenna structure design according to the present invention is shown. Detailed Implementation

[0014] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions of embodiments are intended only to aid in understanding the present invention and do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0015] This invention provides a vertically polarized waveguide antenna structure, which is particularly suitable for the millimeter-wave band and applicable to applications in fields such as vehicle radar, aerospace radar, or communications. It is especially suitable for low-altitude aircraft, achieving the goal of reducing signal attenuation caused by ground reflection and adapting to the omnidirectional communication requirements of low-altitude environments.

[0016] The embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that the positional relationships between the various components in the present invention are described with reference to the horizontal and vertical directions shown in the accompanying drawings.

[0017] Reference Figures 1-5 The vertically polarized waveguide antenna structure 1 includes a waveguide antenna 2, which includes a waveguide feed line 21, a matching element 22, a radiating cavity 23, a radiating slot 24, and a power divider 25. The waveguide feed line 21 serves to transmit or receive radio frequency signals and is an E-plane waveguide transmission line. The radiating cavity 23 is an H-plane waveguide cavity, with both ends of the radiating cavity 23 being closed and short-circuited. Viewed vertically in the figure, the waveguide feed line 21 extends from the middle of the radiating cavity 23 away from the radiating cavity 23, thus forming a T-shape arrangement with the radiating cavity. For example, in... Figure 3As clearly seen, the top surfaces of the radiating cavity 23 and the waveguide feed line 21 are flush. The height of the radiating cavity 23 is approximately half the height of the waveguide feed line 21. Since the radiating cavity 23 is positioned at a portion of the height of the waveguide feed line 21, meaning its height is absorbed by the height of the waveguide feed line 21, it does not add any extra height. This achieves a low profile for the overall waveguide antenna structure. Furthermore, since the waveguide feed line 21 typically operates in the dominant mode (such as the TE10 mode of a rectangular waveguide), the halved height of the radiating cavity 23 creates a gradual transition structure. This height difference allows for mode conversion and impedance matching from the feed waveguide to the radiating cavity without introducing a complex matching network, reducing energy reflection and improving transmission efficiency. The waveguide feed line 21 is short-circuited at its end near the radiating cavity 23. A matching element 22 for matching the waveguide feed line 21 is positioned below the radiating cavity 23. The matching element 22 is preferably a sloping structure, but other forms, such as a stepped structure, can also be used. There are two radiating slots 24, although in other embodiments, the number of radiating slots can also be different. These radiating slots 24 are located above the radiating cavity 23 and are respectively disposed inside the two ends of the radiating cavity 23. The radiating slots 24 connect the radiating cavity 23 and penetrate the top plane of the antenna structure. The horizontal and vertical widths of the radiating beam can be adjusted by adjusting the length, width, and spacing of the radiating slots 24. In the vertical direction shown in the figure, a power divider 25 is disposed between the two radiating slots 24. The power divider 25 extends downward into the radiating cavity 23 and divides the radiating cavity 23 into two radiating regions. The length, width, and height of the power divider 25 can be adjusted appropriately to meet the 3dB power division requirement. By adjusting the size of the power divider 25, the length and width of the radiating slots, the position and slope of the matching body, and other key features, the standing wave bandwidth and radiation efficiency of the antenna can be further optimized.

[0018] like Figure 6 As shown, a beam constraint structure 26 can be set above the radiation slot 24. The beam constraint structure 26 is similar to a horn or stepped structure facing the radiation direction. Using a horn or stepped beam constraint structure can shape the radiation field and concentrate the energy more in a specific direction, thereby compressing the beam width and improving the directional gain of the antenna.

[0019] like Figure 7The diagram illustrates an embodiment of a structural design for a two-stage parallel four-slot vertically polarized waveguide antenna according to the present invention. In this embodiment, the waveguide antenna structure 1 includes two waveguide antennas 2. Specifically, the waveguide feed line 21 first extends vertically, then bends vertically and extends horizontally toward the radiating cavity, and is branched through a multi-stage parallel network to two waveguide antennas 2 arranged side-by-side in the vertical direction. These two waveguide antennas 2 have the same structure as the waveguide antenna 2 described above. Therefore, Figure 7 The antenna in this embodiment includes two waveguide antennas with four radiation slots (as shown in the figure). Of course, the invention is not limited to this; other numbers of parallel-splittered waveguide antennas can also be considered. Multi-stage parallel connection via a centimeter network can create a higher-gain beam characteristic and suppress elevation beamwidth.

[0020] exist Figure 7 In this embodiment, the waveguide antenna structure is divided into upper and lower layers, which are processed separately and then assembled into a whole. Thus, it can be seen that... Figure 7 The increased height of the E-plane waveguide feed line 21 can be placed in the lower structure, so the overall height of the waveguide antenna structure will not increase. This further reduces the cross-section of the overall waveguide antenna structure.

[0021] In an embodiment of the invention, the length ratio of the long side to the wide side of the waveguide feed line 21 is approximately 2:1, and it meets the cutoff requirement for the TE10 mode at the operating frequency. The length ratio of the long side to the wide side of the radiating cavity 23 is approximately 2:1, and it meets the cutoff requirement for the TE10 mode at the operating frequency. The length of the radiating slot 24 is approximately half the operating wavelength, and the spacing of the radiating slots 24 is approximately half the operating wavelength, or adjusted according to the required beamwidth.

[0022] The design structure of this invention is compact, and the cross-sectional height of the complete structure can be controlled within 1-1.5 times the operating wavelength. The design structure conforms to the precision characteristics of conventional metal processing, die casting, and injection molding processes, and is simple to manufacture with controllable costs. The design structure can be manufactured using metal materials or non-metallic materials such as plastics with subsequent surface metallization treatment. When the design structure of this invention is connected in multiple parallel stages through a power divider network, the feed amplitude and / or phase of each gap can be adjusted by adjusting the energy distribution ratio of the power divider network and the position of the matching body within each waveguide stage, thereby optimizing the sidelobe level on the elevation plane.

[0023] In this invention, the waveguide feed line 21 is arranged horizontally, so the electric field direction of the electromagnetic signal transmitted within it is vertical. This electromagnetic signal is distributed equally to the waveguide radiation cavity 23 via the matching body 22 and the power divider 25, and then radiated outward from the horizontally arranged radiation slot 24 (the same applies when receiving). Since the radiation slot 24 is horizontally arranged, its long side is perpendicular to the horizontal direction, and its polarization direction is consistent with the electric field direction of the waveguide feed line. Therefore, the electromagnetic signal radiated or received by the radiation slot 24 is a vertically polarized signal.

[0024] The dimensions of each functional feature in this transmission path (waveguide feeder, matching body, power divider, radiating cavity, radiating slot, etc.) are designed to meet the requirements of the TE10 mode in the operating frequency band, and good VSWR and radiation efficiency are obtained by adjusting the dimensions of appropriate functional features.

[0025] The design structure of this invention realizes a vertically polarized waveguide antenna with a compact structure and an overall profile height that can be controlled within 1-1.5 times the operating wavelength. It is applicable to low-altitude aircraft, automobiles, aerospace and other fields. Especially in the fields of low-altitude aircraft and automobiles, since the operating frequency band is mostly concentrated in the millimeter-wave band of about 60-90 GHz, the relevant functional feature dimensions of this design can generally be controlled at the millimeter level. Therefore, it is particularly beneficial for forging, injection molding, 3D printing and other processes, and especially beneficial for large-scale production and manufacturing, ensuring excellent performance and good cost performance.

[0026] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0027] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments.

[0028] For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A low-profile vertically polarized waveguide antenna structure, comprising a waveguide antenna, the waveguide antenna comprising: The antenna includes a radiating cavity, radiating slots, and a waveguide feed line. The radiating cavity is closed and short-circuited at both ends. The waveguide feed line extends from the middle of the radiating cavity away from it, forming a T-shape with the radiating cavity. The waveguide feed line is short-circuited at its end near the radiating cavity. There are two radiating slots located above the radiating cavity and respectively positioned inside the two ends of the radiating cavity. The radiating slots connect to the radiating cavity and penetrate the top plane of the antenna structure.

2. The waveguide antenna structure as described in claim 1, wherein the top surface of the radiating cavity is flush with the top surface of the waveguide feed line, and the height of the radiating cavity is half the height of the waveguide feed line.

3. The waveguide antenna structure as described in claim 1, wherein a matching body is provided below the radiating cavity, and the matching body is in the form of an inclined structure.

4. The waveguide antenna structure as claimed in claim 1, wherein a power divider is provided between the radiating slots, the power divider extending into the radiating cavity and dividing the radiating cavity into two radiating regions.

5. The waveguide antenna structure as described in claim 1, wherein the radiating cavity is an H-plane waveguide cavity, and the waveguide feed line is an E-plane waveguide transmission line.

6. The waveguide antenna structure as described in claim 1, wherein a beam constraint structure is provided above the radiation slot, the beam constraint structure resembling a horn or a stepped structure facing the radiation direction.

7. The waveguide antenna structure as described in any one of claims 1-6, wherein the length ratio of the long side to the wide side of the waveguide feed line is close to 2:1 and meets the cutoff requirement of the TE10 mode at the operating frequency, and the length ratio of the long side to the wide side of the radiating cavity is close to 2:1 and meets the cutoff requirement of the TE10 mode at the operating frequency.

8. The waveguide antenna structure according to any one of claims 1-6, wherein the length of the radiating slot is half the operating wavelength, and the spacing of the radiating slots is half the operating wavelength.

9. The waveguide antenna structure as described in any one of claims 1-6, wherein the waveguide antenna structure is made of metal or non-metallic materials such as plastic and then subjected to surface metallization treatment.

10. The waveguide antenna structure according to any one of claims 1-6, wherein the waveguide antenna structure comprises a plurality of waveguide antennas, the plurality of waveguide antennas being formed by multi-stage parallel branching through a centimeter network at one end of the waveguide feed line connected to the radiating cavity.

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