Narrow-beam waveguide antenna

Abstract

The invention relates to a narrow-beam waveguide antenna. The broadband waveguide splitter comprises a double-layer structural member and a splitter arranged in the double-layer structural member, wherein the splitter comprises a first waveguide transmission channel, a broadside waveguide and a second waveguide transmission channel; the broadside waveguide is arranged at the tail end of the first waveguide transmission channel, the second waveguide transmission channel is connected with the broadside waveguide to form two branch channels which are arranged in a mirror symmetry mode, the tail end of each branch channel is provided with an output port, and the two output ports output in the same phase; the antenna structure array comprises a plurality of sub antenna structure units and is provided with an antenna radiation cavity, a first slot, a second slot and a radiation opening; the first slot groove comprises a plurality of first unit slot grooves which are arranged in an offset manner relative to the center line of the sub-antenna structure unit, and the second slot groove comprises a plurality of second unit slot grooves which are distributed on the center line of the sub-antenna structure unit. The antenna is simple in structure and small in occupied space, the production and processing cost is reduced, and the antenna has the performance of high gain and low side lobe.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle-mounted radar, and in particular to a narrow-beam waveguide antenna. Background Art

[0002] In a vehicle anti-collision radar system, a narrow-beam antenna is usually combined with a wide-beam antenna to meet the detection requirements at different distances and angles. The narrow-beam antenna has high directivity, which can concentrate radar signals within a smaller beam width, thereby improving the angular resolution. By reducing the beam coverage range, interference signals from other directions can be effectively avoided, the false alarm rate can be reduced, and thus the anti-interference ability of the radar system can be improved. Traditional narrow-beam antennas are composed of a one-to-three power divider plus three sub-antenna units or a one-to-four power divider plus four antenna sub-units. Usually, an unequal power divider is required to meet the performance. At the same time, this also increases the design difficulty and the overall size of the antenna. Summary of the Invention

[0003] Therefore, the present invention provides a narrow-beam waveguide antenna, which has a simple structure, occupies a small space, reduces the production and processing costs, and has the performance of high gain and low side lobes.

[0004] To solve the above technical problems, the present invention provides a narrow-beam waveguide antenna, including a double-layer structure member and the following components arranged inside it: A splitter, including: A first waveguide transmission channel extending along a first direction for receiving horizontally polarized electromagnetic waves; A broadside waveguide arranged at the end of the first waveguide transmission channel and extending along a second direction for converting the horizontally polarized electromagnetic waves into vertically polarized electromagnetic waves; A second waveguide transmission channel connected to the broadside waveguide and extending along both sides of the first direction and then along the second direction to form two mirror-symmetrically arranged branch channels. Output ports are arranged at the ends of the branch channels, and the two output ports output in phase; An antenna structure array communicated with the second waveguide transmission channel. The antenna structure array includes a plurality of sub-antenna structure units distributed along the first direction. Each sub-antenna structure unit includes an antenna radiation cavity, a first slot, a second slot, and a radiation opening that are sequentially communicated along a third direction. The first direction, the second direction, and the third direction are perpendicular to each other pairwise; Among them, the first slot includes a plurality of first unit slots, and the plurality of first unit slots are arranged offset with respect to the center line of the sub-antenna structure unit. The first slots in adjacent sub-antenna structure units are arranged in mirror symmetry, so that the sub-antenna structure units radiate in the same direction. The second slot includes a plurality of second unit slots, and the plurality of second unit slots are distributed on the center line of the sub-antenna structure unit; The first unit slots of each sub-antenna structure unit can achieve in-phase excitation through offset arrangement, and then the vertically polarized electromagnetic wave is transmitted to the corresponding radiation opening and radiated outward in a coupled manner through the second unit slots of each sub-antenna structure unit.

[0005] In an embodiment of the present invention, choke slots extending in the second direction are provided on both sides of the antenna structure array for reducing the sidelobe level and increasing the antenna gain.

[0006] In an embodiment of the present invention, the first unit slots in the first slot are arranged at a spacing of λ / 2, where λ is the wavelength of the electromagnetic wave.

[0007] In an embodiment of the present invention, each sub-antenna structure unit is arranged at a spacing of λ / 2, so that the phases of the electromagnetic signals fed into adjacent sub-antenna structure units are opposite, where λ is the wavelength of the electromagnetic wave.

[0008] In an embodiment of the present invention, a first impedance matching structure and a second impedance matching structure are provided between the end of the first waveguide transmission channel and the wide-side waveguide.

[0009] In an embodiment of the present invention, the first impedance matching structure and the second impedance matching structure are arranged opposite to each other in the third direction and both have an arc-shaped step structure.

[0010] In an embodiment of the present invention, a third impedance matching structure is provided at the connection of the second waveguide transmission channel to the wide-side waveguide, and a third waveguide transmission channel extending in the first direction is provided between the output port and the antenna structure array, and a fourth impedance matching structure is provided on the third waveguide transmission channel.

[0011] In an embodiment of the present invention, the third impedance matching structure and the fourth impedance matching structure are arranged opposite to each other in the third direction and both have an arc-shaped step structure.

[0012] In an embodiment of the present invention, the antenna structure array includes three sub-antenna structure units; each sub-antenna structure unit includes four first slots and four second slots.

[0013] The above technical solution of the present invention has the following advantages compared with the prior art: A narrow-beam waveguide antenna according to the present invention adopts a double-layer combination of a first structural member and a second structural member, integrates an internal waveguide channel and an antenna radiation unit in a limited space, realizes a high degree of integration of internal functional modules, not only meets the requirements of millimeter-wave operation, but also saves space, and realizes a simple overall system structure, easy processing, assembly and maintenance, and reduces the system complexity and manufacturing process requirements.

[0014] Through waveguide splitters and stepped matching of multiple levels (the first, second, third, and fourth impedance matching structures), the present invention ensures the efficient transmission of electromagnetic waves in the splitter and keeps the output signals in phase.

[0015] By reasonably arranging each sub-antenna structural unit, the present invention realizes high gain, greatly improves the concentration of transmitted energy and the long-distance detection ability. The design of the first slot with offset excitation, combined with the mirror-symmetrical arrangement of the sub-antenna units, ensures that the output of each radiation unit always faces the same main direction after excitation. Choke grooves are provided on both sides of the antenna structure array, and by suppressing unnecessary surface currents, the side lobe or sidelobe level is further reduced, so that most of the energy is concentrated in the main lobe, effectively reducing the influence of external interference and spurious signals.

[0016] The present invention adopts center feeding, which can prevent the beam direction from deflecting at different frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the narrow-beam waveguide antenna of the present invention.

[0019] Figure 2 It is a schematic sectional view of the narrow-beam waveguide antenna of the present invention.

[0020] Figure 3 It is a schematic diagram of the internal transmission channel and the antenna structure array of the narrow-beam waveguide antenna of the present invention.

[0021] Figure 4 It is a schematic diagram of the splitter of the present invention.

[0022] Figure 5 It is a schematic top view of the antenna structure array of the present invention.

[0023] Figure 6 It is a schematic rear view of the antenna structure array of the present invention.

[0024] Figure 7It is an axonometric schematic diagram of the antenna structure array of the present invention.

[0025] Figure 8 It is the simulation result of the antenna structure array of the present invention Figure 1 。

[0026] Figure 9 It is the simulation result of the antenna structure array of the present invention Figure 2 。

[0027] Explanation of reference numerals in the specification drawings: 1. First structural member; 2. Second structural member; 3. Splitter; 3-1. First waveguide transmission channel; 3-2. First impedance matching structure; 3-3. Second impedance matching structure; 3-4. Wide-side waveguide; 3-5. Third impedance matching structure; 3-6. Second waveguide transmission channel; 3-6a. Branch channel; 3-7. Third waveguide transmission channel; 3-8. Fourth impedance matching structure; 4. First sub-antenna structure unit; 4-1. First antenna radiation cavity; 4-2. First slot one; 4-2a. First unit slot one; 4-3. Second slot one; 4-3a. Second unit slot one; 4-4. First radiation opening; 5. Second sub-antenna structure unit; 5-1. Second antenna radiation cavity; 5-2. First slot two; 5-2a. First unit slot two; 5-3. Second slot two; 5-3a. Second unit slot two; 5-4. Second radiation opening; 6. Third sub-antenna structure unit; 6-1. Third antenna radiation cavity; 6-2. First slot three; 6-2a. First unit slot three; 6-3. Second slot three; 6-3a. Second unit slot three; 6-4. Third radiation opening; 7. Choke groove. Detailed implementation manners

[0028] The following further illustrates the present invention in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0029] In the present invention, when directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, rather than indicating or implying that the technical features referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0030] In the present invention, the meaning of "several" is one or more, the meaning of "multiple" is more than two, and expressions such as "greater than", "less than", and "exceeding" are understood not to include the recited number; expressions such as "above", "below", and "within" are understood to include the recited number. In the description of the present invention, if there is a description of "first" and "second", they are only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0031] In the present invention, unless otherwise clearly defined, terms such as "arranged", "installed", and "connected" should be understood in a broad sense. For example, they can be directly connected, or indirectly connected through an intermediate medium; they can be fixedly connected, or detachably connected, or integrally formed; they can be mechanically connected, or electrically connected or capable of communicating with each other; they can be the communication inside two components or the interaction relationship between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in the present invention in combination with the specific content of the technical solution.

[0032] Referring to Figure 1 、 Figure 2 As shown, a narrow-beam waveguide antenna of this embodiment includes a double-layer structural member (including a first structural member 1 and a second structural member 2), a splitter 3 and an antenna structure array arranged inside it.

[0033] Referring to Figure 4 As shown, the splitter 3 includes: A first waveguide transmission channel 3-1, extending along a first direction, for receiving horizontally polarized electromagnetic waves; A wide-side waveguide 3-4, arranged at the end of the first waveguide transmission channel 3-1, extending along a second direction, for converting the horizontally polarized electromagnetic waves into vertically polarized electromagnetic waves; A second waveguide transmission channel 3-6, connected to the wide-side waveguide 3-4 and extending along both sides of the first direction and then along the second direction, forming two mirror-symmetrically arranged branch channels 3-6a. Output ports are arranged at the ends of each of the branch channels 3-6a, and the two output ports output in phase (that is, Figure 5 、 Figure 6 the two output ports at A and A' in

[0034] Referring to Figure 3 As shown, the antenna structure array is communicated with the second waveguide transmission channel 3-6, and the antenna structure array includes several sub-antenna structure units distributed along the first direction. In this embodiment, taking three sub-antenna structure units as an example, it includes a first sub-antenna structure unit 4, a second sub-antenna structure unit 5 and a third sub-antenna structure unit 6.

[0035] Referring to Figure 5 、Figure 6 As shown, along the third direction of the first sub - antenna structure unit 4, there are successively connected a first antenna radiation cavity 4 - 1, a first slot 4 - 2, a second slot 4 - 3, and a first radiation opening 4 - 4; Along the third direction of the second sub - antenna structure unit 5, there are successively connected a second antenna radiation cavity 5 - 1, a first slot 5 - 2, a second slot 5 - 3, and a second radiation opening 5 - 4; Along the third direction of the third sub - antenna structure unit 6, there are successively connected a third antenna radiation cavity 6 - 1, a first slot 6 - 2, a second slot 6 - 3, and a third radiation opening 6 - 4.

[0036] Refer to Figure 3 As shown, the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0037] Refer to Figure 5 As shown, the first slot 4 - 2 includes a plurality of first unit slots 4 - 2a, and a plurality of the first unit slots 4 - 2a are arranged offset from the center line of the first sub - antenna structure unit 4. The second slot 4 - 3 includes a plurality of second unit slots 4 - 3a, and a plurality of the second unit slots 4 - 3a are distributed on the center line (a) of the first sub - antenna structure unit 4; The first slot 5 - 2 includes a plurality of first unit slots 5 - 2a, and a plurality of the first unit slots 5 - 2a are arranged offset from the center line of the second sub - antenna structure unit 5. The second slot 5 - 3 includes a plurality of second unit slots 5 - 3a, and a plurality of the second unit slots 5 - 3a are distributed on the center line (b) of the second sub - antenna structure unit 5; The first slot 6 - 2 includes a plurality of first unit slots 6 - 2a, and a plurality of the first unit slots 6 - 2a are arranged offset from the center line of the third sub - antenna structure unit 6. The second slot 6 - 3 includes a plurality of second unit slots 6 - 3a, and a plurality of the second unit slots 6 - 3a are distributed on the center line (c) of the third sub - antenna structure unit 6; All corresponding first unit slots 4 - 2a, all corresponding first unit slots 5 - 2a, and all corresponding first unit slots 6 - 2a are offset and excited in - phase at the opening, and then the vertically polarized electromagnetic wave is transmitted to the corresponding radiation opening and radiated outward in a coupled manner through the corresponding second unit slots 4 - 3a, second unit slots 5 - 3a, and second unit slots 6 - 3a.

[0038] It should be noted that the open - phase excitation is achieved by the offset arrangement of the unit slot gaps in the first slot gap 1 4 - 2, the first slot gap 2 5 - 2, and the first slot gap 3 6 - 2. Then, the electromagnetic signal is transmitted to the first radiation opening 4 - 4, the second radiation opening 5 - 4, and the third radiation opening 6 - 4 in a coupled manner through the unit slot gaps in the second slot gap 1 4 - 3, the second slot gap 2 5 - 3, and the second slot gap 3 6 - 3, and then radiated out.

[0039] In one embodiment, referring to Figure 1 、 Figure 3 As shown, choke slots 7 extending along the second direction are provided on both sides of the antenna structure array for reducing the sidelobe level and increasing the antenna gain. Specifically, when setting, the two choke slots 7 are symmetrically arranged on the second structural member 2.

[0040] Specifically, each first unit slot gap 1 4 - 2a, each first unit slot gap 2 5 - 2a, and each first unit slot gap 3 6 - 2a are arranged at a spacing of λ / 2, where λ is the wavelength of the electromagnetic wave.

[0041] Specifically, the first sub - antenna structure unit 4, the second sub - antenna structure unit 5, and the third sub - antenna structure unit 6 are arranged at a spacing of λ / 2 so that the phases of the electromagnetic signals fed into adjacent sub - antenna structure units are opposite, where λ is the wavelength of the electromagnetic wave.

[0042] Specifically, mirror - symmetric arrangements are made between the adjacent first slot gap 1 4 - 2 and the first slot gap 2 5 - 2, and between the adjacent first slot gap 2 5 - 2 and the first slot gap 3 6 - 2, so that the first sub - antenna structure unit 4, the second sub - antenna structure unit 5, and the third sub - antenna structure unit 6 radiate in the same direction.

[0043] In one embodiment, referring to Figure 4 As shown, a first impedance - matching structure 3 - 2 and a second impedance - matching structure 3 - 3 are provided between the end of the first waveguide transmission channel 3 - 1 and the wide - side waveguide 3 - 4. Specifically, the first impedance - matching structure 3 - 2 and the second impedance - matching structure 3 - 3 are arranged opposite to each other along the third direction and both have an arc - shaped step structure.

[0044] In one embodiment, referring to Figure 6 、 Figure 7 As shown, a third impedance - matching structure 3 - 5 is provided at the connection of the second waveguide transmission channel 3 - 6 with the wide - side waveguide 3 - 4. A third waveguide transmission channel 3 - 7 extending along the first direction is provided between the output port and the antenna structure array, and a fourth impedance - matching structure 3 - 8 is provided on the third waveguide transmission channel 3 - 7. Specifically, the third impedance - matching structure 3 - 5 and the fourth impedance - matching structure 3 - 8 are arranged opposite to each other along the third direction and both have an arc - shaped step structure.

[0045] Referring to Figure 8 as shown, within the range of 76 GHz to 78.9 GHz, the return loss S11 of this narrow-beam waveguide antenna is ≤ -20 dB, indicating that the signal has good transmission performance within this frequency band.

[0046] Referring to Figure 9 as shown, it is the radiation pattern of this narrow-beam waveguide antenna. It can be seen that the antenna gain is 20.2 dBi at 0 deg, and the sidelobe levels in the azimuth plane and elevation plane are ≥ 19.3 dB, having the performance of high gain and low sidelobes, which can improve the detection range of vehicle-mounted radar and enhance the anti-interference ability of the radar system.

[0047] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A narrow-beam waveguide antenna, characterized in that, Comprising a double-layer structural member and those provided inside it: A splitter, comprising: A first waveguide transmission channel extending in a first direction for receiving horizontally polarized electromagnetic waves; A broadside waveguide provided at the end of the first waveguide transmission channel and extending in a second direction for converting the horizontally polarized electromagnetic waves into vertically polarized electromagnetic waves; A second waveguide transmission channel connected to the broadside waveguide and extending along both sides in the first direction and then in the second direction to form two mirror-symmetrically arranged branch channels, with output ports provided at the ends of each of the branch channels, and the two output ports outputting in phase; An antenna structure array communicated with the second waveguide transmission channel, the antenna structure array including a plurality of sub-antenna structure units distributed in the first direction, each of the sub-antenna structure units including an antenna radiation cavity, a first slot, a second slot, and a radiation opening that are sequentially communicated in a third direction, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs; Wherein, the first slot includes a plurality of first unit slots, and the plurality of first unit slots are offset relative to the center line of the sub-antenna structure unit, and the first slots in adjacent sub-antenna structure units are mirror-symmetrically arranged so that the sub-antenna structure units radiate in the same direction, the second slot includes a plurality of second unit slots, and the plurality of second unit slots are distributed on the center line of the sub-antenna structure unit; The first unit slots of each of the sub-antenna structure units can achieve in-phase excitation through offset arrangement, and then the vertically polarized electromagnetic waves are transmitted to the corresponding radiation openings and radiated outward in a coupled manner through the second unit slots of each of the sub-antenna structure units.

2. The narrow-beam waveguide antenna according to claim 1, characterized in that, Choke grooves extending in the second direction are provided on both sides of the antenna structure array for reducing the sidelobe level and increasing the antenna gain.

3. A narrow beam waveguide antenna according to claim 1, characterized in that, The first unit slots in the first slot are arranged at intervals of λ / 2, where λ is the wavelength of the electromagnetic wave.

4. The narrow-beam waveguide antenna according to claim 3, characterized in that, Each of the sub-antenna structure units is arranged at intervals of λ / 2 so that the phases of the electromagnetic signals fed into adjacent sub-antenna structure units are opposite, where λ is the wavelength of the electromagnetic wave.

5. A narrow beam waveguide antenna according to claim 1, characterized in that, A first impedance matching structure and a second impedance matching structure are provided between the end of the first waveguide transmission channel and the broadside waveguide.

6. The narrow-beam waveguide antenna according to claim 5, characterized in that, The first impedance matching structure and the second impedance matching structure are oppositely arranged in the third direction and both have an arc-shaped step structure.

7. A narrow beam waveguide antenna according to claim 1, characterized in that, A third impedance matching structure is provided at the connection of the second waveguide transmission channel with the broadside waveguide, a third waveguide transmission channel extending in the first direction is provided between the output port and the antenna structure array, and a fourth impedance matching structure is provided on the third waveguide transmission channel.

8. A narrow-beam waveguide antenna according to claim 7, characterized in that, The third impedance matching structure and the fourth impedance matching structure are oppositely arranged in the third direction and both have an arc-shaped step structure.

9. A narrow beam waveguide antenna according to claim 1, characterized in that, The antenna structure array includes three sub-antenna structure units; each of the sub-antenna structure units includes four first slots and four second slots.

Images