A narrow beam waveguide antenna

Abstract

The present invention relates to a narrow beam waveguide antenna. The present invention includes a double-layer structure and the following components arranged therein: a splitter including a first waveguide transmission channel, a wideside waveguide, and a second waveguide transmission channel; the wideside waveguide is arranged at the end of the first waveguide transmission channel, and the second waveguide transmission channel is connected to the wideside waveguide to form two branch channels arranged in a mirror-symmetrical manner, and an output port is provided at the end of each branch channel, and the two output ports output in phase; an antenna structure array includes a plurality of sub-antenna structure units, which are provided with an antenna radiation cavity, a first slot, a second slot, and a radiation opening; the first slot includes a plurality of first unit slots, which are arranged offset relative to the center line of the sub-antenna structure unit, and the second slot includes a plurality of second unit slots, which are distributed on the center line of the sub-antenna structure unit. The present invention has a simple structure, occupies a small space, reduces production and processing costs, and has high gain and low sidelobe performance.

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 automotive collision avoidance radar systems, narrow-beam antennas are typically combined with wide-beam antennas to meet detection requirements at different distances and angles. Narrow-beam antennas offer high directivity, concentrating radar signals within a smaller beamwidth, thereby improving angular resolution. By reducing the beam coverage, interference signals from other directions can be effectively avoided, reducing false alarm rates and thus improving the radar system's anti-interference capabilities. Traditional narrow-beam antennas utilize a one-to-three power splitter with three sub-antenna units or a one-to-four power splitter with four antenna sub-units. Typically, the power splitter must be unequally divided to achieve satisfactory performance. This also increases design complexity and the overall size of the antenna. Summary of the Invention

[0003] To this end, the present invention provides a narrow beam waveguide antenna with a simple structure, small footprint, reduced production and processing costs, and high gain and low sidelobe performance.

[0004] To solve the above technical problems, the present invention provides a narrow beam waveguide antenna, comprising a double-layer structure and:

[0005] Splitter, including:

[0006] A first waveguide transmission channel extends along a first direction and is used to receive horizontally polarized electromagnetic waves;

[0007] a broadside waveguide, disposed at an end of the first waveguide transmission channel, extending along a second direction, and configured to convert the horizontally polarized electromagnetic wave into a vertically polarized electromagnetic wave;

[0008] A second waveguide transmission channel is connected to the broadside waveguide and extends along both sides of the first direction and then along the second direction to form two branch channels arranged in a mirror-symmetrical manner. An output port is provided at the end of each branch channel, and the two output ports output in phase;

[0009] An antenna structure array is connected to the second waveguide transmission channel, the antenna structure array includes a plurality of sub-antenna structure units distributed along a first direction, each of the sub-antenna structure units includes an antenna radiation cavity, a first slot, a second slot, and a radiation opening that are sequentially connected along a third direction, and the first direction, the second direction, and the third direction are perpendicular to each other;

[0010] The first slot includes a plurality of first unit slots, which are offset relative to the center line of the sub-antenna structure unit, and the first slots in adjacent sub-antenna structure units are arranged in a mirror-symmetrical manner so that the sub-antenna structure units radiate in the same direction. The second slot includes a plurality of second unit slots, which are distributed on the center line of the sub-antenna structure unit.

[0011] The first unit slots of each sub-antenna structure unit can achieve in-phase excitation through offset arrangement, and then the vertically polarized electromagnetic waves are transmitted to the corresponding radiation openings in a coupled manner through the second unit slots of each sub-antenna structure unit and radiated outward.

[0012] In one embodiment of the present invention, choke slots extending along the second direction are provided on both sides of the antenna structure array to reduce the sidelobe level and improve the antenna gain.

[0013] In one embodiment of the present invention, the first unit slots in the first slots are arranged at a pitch of λ / 2, where λ is the wavelength of the electromagnetic wave.

[0014] In one embodiment of the present invention, the sub-antenna structure units are arranged at a spacing of λ / 2, so that the phases of electromagnetic signals fed into adjacent sub-antenna structure units are opposite, where λ is the wavelength of the electromagnetic wave.

[0015] In one 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 broadside waveguide.

[0016] In one embodiment of the present invention, the first impedance matching structure and the second impedance matching structure are arranged opposite to each other along the third direction and both have an arc-shaped step structure.

[0017] In one embodiment of the present invention, a third impedance matching structure is provided on the second waveguide transmission channel at the connection with the wide-side waveguide, a third waveguide transmission channel extending along 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.

[0018] In one embodiment of the present invention, the third impedance matching structure and the fourth impedance matching structure are arranged opposite to each other along the third direction and both have an arc-shaped step structure.

[0019] In one embodiment of the present invention, 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.

[0020] The above technical solution of the present invention has the following advantages over the prior art:

[0021] The narrow-beam waveguide antenna described in the present invention adopts a double-layer combination of a first structural member and a second structural member to integrate the internal waveguide channel and the antenna radiation unit in a limited space, thereby achieving a high degree of integration of internal functional modules, meeting the millimeter wave working requirements while saving space, and realizing a simple overall system structure that is easy to process, assemble and maintain, thereby reducing system complexity and manufacturing process requirements.

[0022] The present invention ensures efficient transmission of electromagnetic waves in the splitter and keeps the output signals in phase through a waveguide splitter and multi-stage (first, second, third, and fourth impedance matching structures) step-type matching.

[0023] The rational arrangement of the sub-antenna structural units in this invention achieves high gain, significantly improving the concentration of transmitted energy and long-range detection capabilities. The offset-excitation first slot design, coupled with the mirror-symmetrical arrangement of the sub-antenna units, ensures that the output of each radiating element, after excitation, always points in the same main direction. Choke slots are placed on both sides of the antenna structure array to further reduce sidelobe or sidelobe levels by suppressing unnecessary surface currents, thereby concentrating the majority of energy within the main lobe and effectively minimizing the impact of external interference and stray signals.

[0024] The present invention adopts central feeding, which can prevent beam pointing from deflecting at different frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of the overall structure of the narrow beam waveguide antenna of the present invention.

[0027] Figure 2 It is a cross-sectional schematic diagram of the narrow beam waveguide antenna of the present invention.

[0028] Figure 3 It is a schematic diagram of the internal transmission channel and antenna structure array of the narrow beam waveguide antenna of the present invention.

[0029] Figure 4 Schematic diagram of the splitter of the present invention.

[0030] Figure 5 It is a top view schematic diagram of the antenna structure array of the present invention.

[0031] Figure 6 It is a rear view schematic diagram of the antenna structure array of the present invention.

[0032] Figure 7It is an axial schematic diagram of the antenna structure array of the present invention.

[0033] Figure 8 This is the simulation result of the antenna structure array of the present invention Figure 1 .

[0034] Figure 9 This is the simulation result of the antenna structure array of the present invention Figure 2 .

[0035] Description of the accompanying drawings:

[0036] 1. The first structural member;

[0037] 2. Second structural member;

[0038] 3. Splitter; 3-1. First waveguide transmission channel; 3-2. First impedance matching structure; 3-3. Second impedance matching structure; 3-4. Broadside 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;

[0039] 4. First sub-antenna structure unit; 4-1. First antenna radiation cavity; 4-2. First slot slot 1; 4-2a. First unit slot slot 1; 4-3. Second slot slot 1; 4-3a. Second unit slot slot 1; 4-4. First radiation opening;

[0040] 5. Second sub-antenna structure unit; 5-1. Second antenna radiation cavity; 5-2. First slot slot 2; 5-2a. First unit slot slot 2; 5-3. Second slot slot 2; 5-3a. Second unit slot slot 2; 5-4. Second radiation opening;

[0041] 6. Third sub-antenna structure unit; 6-1. Third antenna radiation cavity; 6-2. First slot slot three; 6-2a. First unit slot slot three; 6-3. Second slot slot three; 6-3a. Second unit slot slot three; 6-4. Third radiation opening;

[0042] 7. Choke slot. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0044] In the present invention, if 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, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0045] In the present invention, "several" means one or more, "multiple" means more than two, "greater than," "less than," "exceeds," etc. are understood to exclude the number itself; "above," "below," "within," etc. are understood to include the number itself. In the description of the present invention, the use of "first" or "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0046] In the present invention, unless otherwise expressly defined, terms such as "disposed," "installed," and "connected" should be interpreted broadly. For example, they may refer to direct connection or indirect connection through an intermediate medium; fixed connection or detachable connection or integral molding; mechanical connection or electrical connection or mutual communication; and internal connection between two components or interaction between two components. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0047] Reference Figure 1 、 Figure 2 As shown, a narrow beam waveguide antenna of this embodiment includes a double-layer structure (including a first structure 1 and a second structure 2), a splitter 3 arranged therein, and an antenna structure array.

[0048] Reference Figure 4 As shown, the splitter 3 includes:

[0049] A first waveguide transmission channel 3-1 extends along a first direction and is used to receive horizontally polarized electromagnetic waves;

[0050] a broadside waveguide 3-4, provided at the end of the first waveguide transmission channel 3-1, extending along the second direction, and configured to convert the horizontally polarized electromagnetic wave into a vertically polarized electromagnetic wave;

[0051] The second waveguide transmission channel 3-6 is connected to the broadside waveguide 3-4 and extends along both sides of the first direction and then extends along the second direction to form two mirror-symmetrically arranged branch channels 3-6a. An output port is provided at the end of each branch channel 3-6a, and the two output ports output in phase (i.e. Figure 5 、 Figure 6 The two output ports at A and A' are in phase with each other).

[0052] Reference Figure 3As shown, the antenna structure array is connected to the second waveguide transmission channel 3-6, and the antenna structure array includes a plurality of sub-antenna structure units distributed along the first direction. This embodiment takes three sub-antenna structure units as an example, including a first sub-antenna structure unit 4, a second sub-antenna structure unit 5, and a third sub-antenna structure unit 6.

[0053] Reference Figure 5 、 Figure 6 As shown, along the third direction of the first sub-antenna structure unit 4, a first antenna radiation cavity 4-1, a first slot groove 1 4-2, a second slot groove 1 4-3 and a first radiation opening 4-4 are provided which are connected in sequence;

[0054] Along the third direction of the second sub-antenna structure unit 5, a second antenna radiation cavity 5-1, a first slot second 5-2, a second slot second 5-3 and a second radiation opening 5-4 are provided which are connected in sequence;

[0055] Along the third direction of the third sub-antenna structure unit 6, there are provided a third antenna radiation cavity 6-1, a first slot three 6-2, a second slot three 6-3 and a third radiation opening 6-4 which are connected in sequence.

[0056] Reference Figure 3 As shown, the first direction, the second direction and the third direction are perpendicular to each other.

[0057] Reference Figure 5 As shown, the first slot slot 4-2 includes a plurality of first unit slot slots 4-2a, and the plurality of first unit slot slots 4-2a are offset relative to the center line of the first sub-antenna structure unit 4. The second slot slot 4-3 includes a plurality of second unit slot slots 4-3a, and the plurality of second unit slot slots 4-3a are distributed on the center line (a) of the first sub-antenna structure unit 4.

[0058] The first slot slot 5-2 includes a plurality of first unit slot slots 5-2a, and the plurality of first unit slot slots 5-2a are arranged offset relative to the center line of the second sub-antenna structure unit 5. The second slot slot 5-3 includes a plurality of second unit slot slots 5-3a, and the plurality of second unit slot slots 5-3a are distributed on the center line (b) of the second sub-antenna structure unit 5.

[0059] The first slot three 6-2 includes a plurality of first unit slot threes 6-2a, and the plurality of first unit slot threes 6-2a are arranged offset relative to the center line of the third sub-antenna structure unit 6. The second slot three 6-3 includes a plurality of second unit slot threes 6-3a, and the plurality of second unit slot threes 6-3a are distributed on the center line (c) of the third sub-antenna structure unit 6.

[0060] All corresponding first unit slots 1 4-2a, all corresponding first unit slots 2 5-2a, and all corresponding first unit slots 3 6-2a offset the excitation openings in phase, and then transmit the vertically polarized electromagnetic waves to the corresponding radiation openings in a coupled manner through the corresponding second unit slots 1 4-3a, second unit slots 2 5-3a, and second unit slots 3 6-3a and radiate outward.

[0061] It should be noted that the openings are excited in phase by the offset arrangement of the unit slots in the first slot one 4-2, the first slot two 5-2 and the first slot three 6-2, and 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 coupling manner with the unit slots in the second slot one 4-3, the second slot two 5-3 and the second slot three 6-3, and then radiated out.

[0062] In one embodiment, referring to Figure 1 、 Figure 3 As shown, the antenna structure array is provided with choke slots 7 extending along the second direction on both sides thereof, for reducing the side lobe level and improving the antenna gain. In a specific configuration, the two choke slots 7 are symmetrically arranged on the second structure member 2.

[0063] Specifically, each first unit slot 1 4 - 2 a , each first unit slot 2 5 - 2 a , and each first unit slot 3 6 - 2 a are arranged at a pitch of λ / 2, where λ is the wavelength of the electromagnetic wave.

[0064] 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 electromagnetic signals fed into adjacent sub-antenna structure units are opposite, where λ is the wavelength of the electromagnetic wave.

[0065] Specifically, the adjacent first slot slot 1 4-2 and the first slot slot 2 5-2, and the adjacent first slot slot 2 5-2 and the first slot slot 3 6-2 are arranged in mirror symmetry 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.

[0066] In one embodiment, referring to Figure 4As 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 broadside 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.

[0067] In one embodiment, referring to Figure 6 、 Figure 7 As shown, a third impedance matching structure 3-5 is provided on the second waveguide transmission channel 3-6 at the junction with the broadside 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. 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 each other along the third direction and both have an arc-shaped step structure.

[0068] Reference Figure 8 As shown, the narrow beam waveguide antenna has a return loss S11≤-20dB in the range of 76GHz to 78.9GHz, indicating that the signal has good transmission performance in this frequency band.

[0069] Reference Figure 9 As shown in the figure, this is the radiation pattern of the narrow beam waveguide antenna. It can be seen that the antenna gain is 20.2dBi at 0deg, and the sidelobe levels in the azimuth and elevation planes are ≥19.3dB. It has high gain and low sidelobe performance, which can improve the detection range of the vehicle-mounted radar and enhance the anti-interference capability of the radar system.

[0070] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A narrow beam waveguide antenna, characterized in that: Including double-layer structural parts and the following components arranged therein: Splitter, including: A first waveguide transmission channel extends along a first direction and is used to receive horizontally polarized electromagnetic waves; a broadside waveguide, disposed at an end of the first waveguide transmission channel, extending along a second direction, and configured to convert the horizontally polarized electromagnetic wave into a vertically polarized electromagnetic wave; A second waveguide transmission channel is connected to the broadside waveguide and extends along both sides of the first direction and then along the second direction to form two branch channels arranged mirror-symmetrically with respect to the symmetrical cross-section of the second waveguide transmission channel, wherein an output port is provided at the end of each branch channel, and the two output ports output in phase; An antenna structure array is connected to the second waveguide transmission channel, the antenna structure array includes a plurality of sub-antenna structure units distributed along a first direction, each of the sub-antenna structure units includes an antenna radiation cavity, a first slot, a second slot, and a radiation opening that are sequentially connected along a third direction, and the first direction, the second direction, and the third direction are perpendicular to each other; The first slot includes a plurality of first unit slots, which are offset relative to the center line of the sub-antenna structure unit. The first slots in adjacent sub-antenna structure units are arranged in a mirror-symmetrical manner about the symmetry plane between the adjacent sub-antenna structure units, so that the sub-antenna structure units radiate in the same direction. The second slot includes a plurality of second unit slots, which 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 waves are transmitted to the corresponding radiation openings in a coupled manner through the second unit slots of each sub-antenna structure unit and radiated outward.

2. The narrow beam waveguide antenna according to claim 1, characterized in that: Choke slots extending along the second direction are provided on both sides of the antenna structure array, so as to reduce the side lobe level and improve the antenna gain.

3. The narrow beam waveguide antenna according to claim 1, characterized in that: The first unit slots in the first slots are arranged at a pitch 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: The sub-antenna structure units are arranged at a spacing of λ / 2, so that the phases of electromagnetic signals fed into adjacent sub-antenna structure units are opposite, where λ is the wavelength of the electromagnetic wave.

5. The 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 arranged opposite to each other along the third direction and both have an arc-shaped step structure.

7. The narrow beam waveguide antenna according to claim 1, characterized in that: A third impedance matching structure is provided on the second waveguide transmission channel at the connection with the wide-side waveguide, a third waveguide transmission channel extending along 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. The narrow beam waveguide antenna according to claim 7, characterized in that: The third impedance matching structure and the fourth impedance matching structure are arranged opposite to each other along the third direction and both have an arc-shaped step structure.

9. The 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.

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