Forward millimeter wave radar antenna

Abstract

The invention relates to a forward millimeter wave radar antenna. The antenna comprises a body, a wide-beam waveguide antenna, a narrow-beam waveguide antenna and waveguide transmission channels, wherein the wide-beam waveguide antenna, the narrow-beam waveguide antenna and the waveguide transmission channels are integrated in the body; the waveguide transmission channels comprise a first waveguide transmission channel and a second waveguide transmission channel; the wide-beam waveguide antenna comprises a polarization conversion structure; the antenna unit comprises a first antenna radiation cavity, a first slot radiation slot and a first opening horn which are connected in sequence, and the polarization conversion structure is connected with the first antenna radiation cavity; a first choke groove; the narrow-beam waveguide antenna comprises a splitter which is connected with the second waveguide transmission channel; the antenna structure array comprises a plurality of sub-antenna structure units, and each sub-antenna structure unit comprises a second antenna radiation cavity, a second slot radiation slot and a second opening horn which are connected in sequence; and the second choke groove is arranged beside the antenna structure array. According to the invention, the requirements of short-distance wide-angle coverage and long-distance high-precision detection are met, and the production cost is reduced.

Description

Technical Field

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

[0002] In a vehicle-mounted millimeter-wave radar system, compared with a traditional printed circuit board microstrip antenna, a waveguide antenna has the advantages of low loss, high efficiency, and relatively wide bandwidth. Currently, the radar antenna has a three-layer waveguide structure, but such a structure is relatively complex, has a high processing cost, and is not conducive to welding. In addition, a single type of antenna often has difficulty in meeting the requirements of existing vehicle-mounted radars for different scenarios. Summary of the Invention

[0003] For this reason, the present invention provides a forward millimeter-wave radar antenna. By integrating a wide-beam waveguide antenna and a narrow-beam waveguide antenna on two structural members, the requirements of short-distance wide-angle coverage and long-distance high-precision detection are achieved, the production cost is reduced, and the high-gain, low-side-lobe, and relatively wide bandwidth performance are taken into account, which is beneficial to improving the comprehensive detection ability of the vehicle-mounted radar.

[0004] To solve the above technical problems, the present invention provides a forward millimeter-wave radar antenna, including a body and a wide-beam waveguide antenna, a narrow-beam waveguide antenna, and a waveguide transmission channel integrally arranged in the body. The waveguide transmission channel includes a first waveguide transmission channel and a second waveguide transmission channel; Wherein, the wide-beam waveguide antenna includes: A polarization conversion structure, arranged at the end of the first waveguide transmission channel, for converting the electromagnetic wave horizontal polarization direction in the first waveguide transmission channel into a vertical polarization direction; An antenna unit, including a first antenna radiation cavity, a first slot radiation groove, and a first open horn connected in sequence. The polarization conversion structure is connected to the first antenna radiation cavity; A first choke slot, arranged beside the first open horn; [[ID=2 and 5]] Wherein, the narrow-beam waveguide antenna includes: A splitter, whose input end is connected to the second waveguide transmission channel to split the signal energy in the second waveguide transmission channel and then transmit it; An antenna structure array, including a plurality of sub-antenna structure units connected to the output end of the splitter. Each sub-antenna structure unit includes a second antenna radiation cavity, a second slot radiation groove, and a second open horn connected in sequence; A second choke slot, arranged beside the antenna structure array; Wherein, the body includes a first structural member and a second structural member connected to each other. Two parts of each of the wide-beam waveguide antenna and the narrow-beam waveguide antenna are respectively disposed on the first structural member and the second structural member. A waveguide transmission interface interconnected with the chip is formed on the first structural member, configured to transmit signals from the chip to the first waveguide transmission channel and the second waveguide transmission channel, and radiate them out through the wide-beam waveguide antenna and the narrow-beam waveguide antenna respectively.

[0005] In an embodiment of the present invention, the first waveguide transmission channel includes a first waveguide transmission channel one, a first waveguide transmission channel two, and a first waveguide transmission channel three connected in sequence. The first waveguide transmission channel one extends along a first direction, the first waveguide transmission channel three extends along a second direction, and the first waveguide transmission channel two is disposed obliquely in a transitional manner between the first waveguide transmission channel one and the first waveguide transmission channel three; the first antenna radiation cavity, the first slot radiation groove, and the first open horn are sequentially disposed along a third direction; The first antenna radiation cavity and the first open horn respectively extend along the second direction, and a plurality of the first slot radiation grooves are distributed along the second direction; The first direction, the second direction, and the third direction are perpendicular to each other in pairs; The polarization conversion structure is disposed at the end of the first waveguide transmission channel three.

[0006] In an embodiment of the present invention, the polarization conversion structure is located at the middle position on the side of the first antenna radiation cavity; a first impedance matching structure is disposed at the head end of the first waveguide transmission channel one; a second impedance matching structure is disposed at a position of the first antenna radiation cavity close to the polarization conversion structure.

[0007] In an embodiment of the present invention, the first choke groove extends along the second direction, and two of the first choke grooves are symmetrically disposed on both sides of the first open horn along the first direction.

[0008] In an embodiment of the present invention, the second waveguide transmission channel includes a second waveguide transmission channel one, a second waveguide transmission channel two, and a second waveguide transmission channel three connected in sequence. The second waveguide transmission channel one and the second waveguide transmission channel three extend along the first direction, and the second waveguide transmission channel two extends along the second direction; A plurality of the sub-antenna structure units are distributed along the first direction, and the second antenna radiation cavity, the second slot radiation groove, and the second open horn are sequentially disposed along the third direction; The second antenna radiation cavity and the second open horn extend along the second direction respectively, and a plurality of the second slot radiation grooves are distributed along the second direction; The first direction, the second direction and the third direction are perpendicular to each other pairwise.

[0009] In an embodiment of the present invention, a third impedance matching structure is arranged at the bottom of the second antenna radiation cavity, and a fourth impedance matching structure is arranged at the head end of the first second waveguide transmission channel.

[0010] In an embodiment of the present invention, the second choke groove extends along the second direction, and two second choke grooves are symmetrically arranged on both sides of the antenna structure array along the first direction.

[0011] In an embodiment of the present invention, the splitter includes a plurality of power branch paths extending along the second direction, each power branch path extends between two adjacent second antenna radiation cavities, and first branches and second branches extending along both sides of the first direction are arranged at the ends of each power branch path, and the first branch and the second branch are respectively connected to two adjacent second antenna radiation cavities.

[0012] In an embodiment of the present invention, a sixth impedance matching structure is further arranged between the end of the third second waveguide transmission channel and the splitter, a sub-channel extending along the first direction is arranged between the sixth impedance matching structure and the two power branch paths, and a fifth impedance matching structure is arranged on the sub-channel.

[0013] In an embodiment of the present invention, a seventh impedance matching structure and an eighth impedance matching structure are respectively arranged on both sides of the end of the power branch path along the third direction.

[0014] The above technical solution of the present invention has the following advantages compared with the prior art: A forward millimeter-wave radar antenna of the present invention integrates a wide-beam waveguide antenna and a narrow-beam waveguide antenna on two-layer structural members. The wide-beam part is mainly used for short-range and large-range detection, while the narrow-beam part is used for long-range and high-precision detection. Through the synergistic effect of the two, the detection performance of the vehicle-mounted radar in different scenarios can be significantly improved.

[0015] In addition, the present invention adopts a two-layer structure design, which is more convenient for processing and assembly, thereby reducing the production cost; by using the layout of narrow-side feeding and narrow-side radiation cavities, the size of the waveguide antenna in the horizontal direction is effectively reduced, meeting the requirements of compact installation; the wide-beam antenna not only has a high gain, but also has a wide beam coverage and low side lobes, which can meet the needs of short-range and large-range detection; the narrow-beam antenna also has the characteristics of high gain and low side lobes, enabling it to provide higher precision in long-range detection. Description of the Drawings

[0016] In order to make the content of the present invention easier to be clearly understood, the present invention will be further described in detail below according to specific embodiments of the present invention in conjunction with the drawings.

[0017] Figure 1 It is a schematic diagram of the overall structure of the forward millimeter-wave radar antenna of the present invention.

[0018] Figure 2 It is a schematic diagram of the first perspective of the cross-section of the forward millimeter-wave radar antenna of the present invention.

[0019] Figure 3 It is a schematic diagram of the second perspective of the cross-section of the forward millimeter-wave radar antenna of the present invention.

[0020] Figure 4 It is a schematic axonometric structure diagram of the wide-beam waveguide antenna of the present invention.

[0021] Figure 5 It is a schematic front view structure diagram of the narrow-beam waveguide antenna of the present invention.

[0022] Figure 6 It is a schematic axonometric structure diagram of the narrow-beam waveguide antenna of the present invention.

[0023] Figure 7 It is a schematic structure diagram of the splitter of the present invention.

[0024] Figure 8 It is a simulation schematic diagram of the wide-beam waveguide antenna of the present invention.

[0025] Figure 9 It is the radiation pattern of the wide-beam waveguide antenna of the present invention.

[0026] Figure 10 It is a simulation schematic diagram of the narrow-beam waveguide antenna of the present invention.

[0027] Figure 11 It is the radiation pattern of the narrow-beam waveguide antenna of the present invention.

[0028] Description of the reference numerals in the drawings: 1. First structural member; 2. Second structural member; 3. Wide-beam waveguide antenna; 3-1. First antenna radiation cavity; 3-2. Second impedance matching structure; 3-3. First slot radiation groove; 3-4. First open horn; 3-5. First choke groove; 4. Narrow-beam waveguide antenna; 4a. Sub-antenna structure unit; 4-1. Second antenna radiation cavity; 4-2. Second slot radiation groove; 4-3. Second open horn; 4-4. Second choke groove; 4-5. Third impedance matching structure; 5. Waveguide transmission channels; 5-1. First waveguide transmission channel; 5-1a. First waveguide transmission channel 1; 5-1b. First waveguide transmission channel 2; 5-1c. First waveguide transmission channel 3; 5-1-1. First impedance matching structure; 5-1-2. Polarization conversion structure; 5-2. Second waveguide transmission channel; 5-2a. Second waveguide transmission channel 1; 5-2b. Second waveguide transmission channel 2; 5-2c. Second waveguide transmission channel 3; 5-2-1. Fourth impedance matching structure; 6. Waveguide transmission interface; 7. Splitter; 7-1. Fifth impedance matching structure; 7-2. Sixth impedance matching structure; 7-3. Power branch; 7-4. Seventh impedance matching structure; 7-5. Eighth impedance matching structure; 7-6. First branch; 7-7. Second branch; 7-8. Sub-channel. Detailed implementation manners

[0029] The present invention will be further described below in conjunction with the accompanying 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 are not intended to limit the present invention.

[0030] 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, so it cannot be understood as a limitation to the present invention.

[0031] In the present invention, the meaning of "several" is one or more, the meaning of "multiple" is two or more, and "greater than", "less than", "exceeding", etc. are understood not to include the present number; "above", "below", "within", etc. are understood to include the present number. In the description of the present invention, if "first" and "second" are described, 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.

[0032] In the present invention, unless otherwise clearly defined, words such as "set", "installed", "connected", etc. 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 meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0033] Refer to Figures 1 to 3As shown in the figure, a forward millimeter-wave radar antenna of the present invention includes a body and a wide-beam waveguide antenna 3, a narrow-beam waveguide antenna 4, and a waveguide transmission channel 5 integrally provided in the body. The waveguide transmission channel 5 includes a first waveguide transmission channel 5-1 and a second waveguide transmission channel 5-2; Among them, the wide-beam waveguide antenna 3 includes: A polarization conversion structure 5-1-2, arranged at the end of the first waveguide transmission channel 5-1, for converting the electromagnetic wave horizontal polarization direction in the first waveguide transmission channel 5-1 into a vertical polarization direction; An antenna unit, including a first antenna radiation cavity 3-1, a first slot radiation groove 3-3, and a first open horn 3-4 connected in sequence. The polarization conversion structure 5-1-2 is connected to the first antenna radiation cavity 3-1; A first choke groove 3-5, arranged beside the first open horn 3-4; Among them, the narrow-beam waveguide antenna 4 includes: A splitter 7, whose input end is connected to the second waveguide transmission channel 5-2 to split the signal energy in the second waveguide transmission channel 5-2 and then transmit it; An antenna structure array, including a plurality of sub-antenna structure units 4a connected to the output end of the splitter 7. Each of the sub-antenna structure units 4a includes a second antenna radiation cavity 4-1, a second slot radiation groove 4-2, and a second open horn 4-3 connected in sequence; A second choke groove 4-4, arranged beside the antenna structure array; Among them, the body includes a first structural member 1 and a second structural member 2 connected to each other. Two parts of the wide-beam waveguide antenna 3 and the narrow-beam waveguide antenna 4 are respectively arranged on the first structural member 1 and the second structural member 2. A waveguide transmission interface 6 for chip interconnection is provided on the first structural member 1, used to transmit the signal from the chip to the first waveguide transmission channel 5-1 and the second waveguide transmission channel 5-2, and radiate them out through the wide-beam waveguide antenna 3 and the narrow-beam waveguide antenna 4 respectively.

[0034] By integrating the wide-beam waveguide antenna 3 and the narrow-beam waveguide antenna 4 on two layers of structural members, the wide-beam part is mainly used to realize short-range and large-range detection, while the narrow-beam part is used for long-range and high-precision detection. Through the synergistic effect of the two, the detection performance of the vehicle-mounted radar in different scenarios can be significantly improved.

[0035] In addition, the present invention adopts a two-layer structure design, which is more convenient for processing and assembly, thus reducing the production cost; by using the layout of narrow-side feeding and narrow-side radiation cavities, the size of the waveguide antenna in the horizontal direction is effectively reduced to meet the requirements of compact installation; the wide-beam antenna not only has a high gain, but also has a wide beam coverage and low side lobes, which can meet the needs of short-distance and large-range detection; the narrow-beam antenna also has the characteristics of high gain and low side lobes, enabling it to provide higher accuracy in long-distance detection.

[0036] Specifically, referring to Figure 4 As shown, the first waveguide transmission channel 5-1 includes a first waveguide transmission channel part one 5-1a, a first waveguide transmission channel part two 5-1b, and a first waveguide transmission channel part three 5-1c that are connected in sequence. The first waveguide transmission channel part one 5-1a extends along a first direction, the first waveguide transmission channel part three 5-1c extends along a second direction, and the first waveguide transmission channel part two 5-1b is transitionally inclined and arranged between the first waveguide transmission channel part one 5-1a and the first waveguide transmission channel part three 5-1c; the first antenna radiation cavity 3-1, the first slot radiation groove 3-3, and the first open horn 3-4 are arranged in sequence along a third direction; The first antenna radiation cavity 3-1 and the first open horn 3-4 respectively extend along the second direction, and a plurality of the first slot radiation grooves 3-3 are distributed along the second direction; The first direction (X), the second direction (Y), and the third direction (Z) are perpendicular to each other in pairs; The polarization conversion structure 5-1-2 is arranged at the end of the first waveguide transmission channel part three 5-1c.

[0037] Specifically, the polarization conversion structure 5-1-2 is located at the middle position on the side of the first antenna radiation cavity 3-1; a first impedance matching structure 5-1-1 is arranged at the head end of the first waveguide transmission channel part one 5-1a; a second impedance matching structure 3-2 is arranged at the position of the first antenna radiation cavity 3-1 close to the polarization conversion structure 5-1-2.

[0038] Specifically, the first choke groove 3-5 extends along the second direction, and two of the first choke grooves 3-5 are symmetrically arranged on both sides of the first open horn 3-4 along the first direction.

[0039] Specifically, referring to Figure 5 、 Figure 6As shown, the second waveguide transmission channel 5-2 includes a first second waveguide transmission channel 5-2a, a second second waveguide transmission channel 5-2b, and a third second waveguide transmission channel 5-2c that are connected in sequence. The first second waveguide transmission channel 5-2a and the third second waveguide transmission channel 5-2c extend along a first direction, and the second second waveguide transmission channel 5-2b extends along a second direction; A plurality of the sub-antenna structure units 4a are distributed along the first direction, and the second antenna radiation cavity 4-1, the second slot radiation groove 4-2, and the second open horn 4-3 are arranged in sequence along a third direction; The second antenna radiation cavity 4-1 and the second open horn 4-3 respectively extend along the second direction, and a plurality of the second slot radiation grooves 4-2 are distributed along the second direction; The first direction (X), the second direction (Y), and the third direction (Z) are perpendicular to each other in pairs.

[0040] Specifically, a third impedance matching structure 4-5 is provided at the bottom of the second antenna radiation cavity 4-1, and a fourth impedance matching structure 5-2-1 is provided at the head end of the first second waveguide transmission channel 5-2a.

[0041] Specifically, the second choke groove 4-4 extends along the second direction, and two second choke grooves 4-4 are symmetrically arranged on both sides of the antenna structure array along the first direction.

[0042] Referring to Figure 7 As shown, the narrow-beam waveguide antenna 4 is used for the transmission and distribution of signal energy by the second waveguide transmission channel 5-2 and the splitter 7. The splitter 7 includes a plurality of power branch paths 7-3 that extend along the second direction. Each power branch path 7-3 extends between two adjacent second antenna radiation cavities 4-1. A first branch 7-6 and a second branch 7-7 that extend along both sides of the first direction are provided at the ends of each power branch path 7-3. The first branch 7-6 and the second branch 7-7 are respectively connected to two adjacent second antenna radiation cavities 4-1. In this embodiment, there are two power branch paths 7-3 and three sub-antenna structure units 4a. The splitter 7 divides the signal energy in the second waveguide transmission channel (5-2) into two parts and transmits it to the narrow-beam waveguide antenna 4, and then radiates it out.

[0043] Specifically, a sixth impedance matching structure 7-2 is further provided between the end of the third second waveguide transmission channel 5-2c and the splitter 7. A sub-channel 7-8 that extends along the first direction is provided between the sixth impedance matching structure 7-2 and the two power branch paths 7-3, and a fifth impedance matching structure 7-1 is provided on the sub-channel 7-8.

[0044] Specifically, on both sides of the end of the power branch 7-3 along the third direction, a seventh impedance matching structure 7-4 and an eighth impedance matching structure 7-5 are respectively arranged.

[0045] In one embodiment, the first impedance matching structure 5-1-1 to the eighth impedance matching structure 7-5 all include an arc-shaped step structure.

[0046] Refer to Figure 8 As shown, for the wide-beam waveguide antenna 3 within 76 - 79 GHz, the return loss S11 ≤ -20 dB, indicating that the signal has good transmission performance within this frequency band.

[0047] Refer to Figure 9 As shown, it is the radiation pattern of the wide-beam waveguide antenna 3. It can be known that the antenna gain is 15.7 dBi@0° (the gain in the 0° direction is 15.7 dBi), and the sidelobe level ≥ 21.7 dB.

[0048] Refer to Figure 10 As shown, for the narrow-beam waveguide antenna 4 within 76 - 79 GHz, the return loss S11 ≤ -20 dB, indicating that the signal has good transmission performance within this frequency band.

[0049] Refer to Figure 11 As shown, it is the radiation pattern of the narrow-beam waveguide antenna 4. It can be known that the antenna gain is 20.5 dBi@0° (the gain in the 0° direction is 20.5 dBi), and the sidelobe level ≥ 18.3 dB. It has the performance of high gain and low sidelobes, which can improve the detection range of the vehicle-mounted radar and enhance the anti-interference ability of the radar system.

[0050] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the embodiments, 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 by the scope of the claims of the present invention.

Claims

1. A forward millimeter-wave radar antenna, characterized in that, It includes a body, a wide-beam waveguide antenna (3), a narrow-beam waveguide antenna (4), and a waveguide transmission channel (5) integrally provided in the body. The waveguide transmission channel (5) includes a first waveguide transmission channel (5-1) and a second waveguide transmission channel (5-2). Among them, the wide-beam waveguide antenna (3) includes: A polarization conversion structure (5-1-2) is provided at the end of the first waveguide transmission channel (5-1) for converting the electromagnetic wave in the first waveguide transmission channel (5-1) from the horizontal polarization direction to the vertical polarization direction. An antenna unit includes a first antenna radiation cavity (3-1), a first slot radiation groove (3-3), and a first open horn (3-4) connected in sequence. The polarization conversion structure (5-1-2) is connected to the first antenna radiation cavity (3-1). A first choke groove (3-5) is provided beside the first open horn (3-4). Among them, the narrow-beam waveguide antenna (4) includes: A splitter (7), whose input end is connected to the second waveguide transmission channel (5-2) to split the signal energy in the second waveguide transmission channel (5-2) and then transmit it. An antenna structure array includes a plurality of sub-antenna structure units (4a) connected to the output end of the splitter (7). Each sub-antenna structure unit (4a) includes a second antenna radiation cavity (4-1), a second slot radiation groove (4-2), and a second open horn (4-3) connected in sequence. A second choke groove (4-4) is provided beside the antenna structure array. Among them, the body includes a first structural member (1) and a second structural member (2) connected to each other. Two parts of the wide-beam waveguide antenna (3) and the narrow-beam waveguide antenna (4) are respectively arranged on the first structural member (1) and the second structural member (2). A waveguide transmission interface (6) for chip interconnection is provided on the first structural member (1) to transmit the signal from the chip to the first waveguide transmission channel (5-1) and the second waveguide transmission channel (5-2), and radiate them out through the wide-beam waveguide antenna (3) and the narrow-beam waveguide antenna (4) respectively.

2. The forward millimeter-wave radar antenna according to claim 1, characterized in that, The first waveguide transmission channel (5-1) includes a first waveguide transmission channel one (5-1a), a first waveguide transmission channel two (5-1b), and a first waveguide transmission channel three (5-1c) connected in sequence. The first waveguide transmission channel one (5-1a) extends along a first direction, the first waveguide transmission channel three (5-1c) extends along a second direction, and the first waveguide transmission channel two (5-1b) is transitionally inclined between the first waveguide transmission channel one (5-1a) and the first waveguide transmission channel three (5-1c); the first antenna radiation cavity (3-1), the first slot radiation groove (3-3), and the first open horn (3-4) are arranged in sequence along a third direction. The first antenna radiation cavity (3-1) and the first open horn (3-4) extend along the second direction respectively, and a plurality of the first slot radiation grooves (3-3) are distributed along the second direction; The first direction, the second direction and the third direction are perpendicular to each other in pairs; The polarization conversion structure (5-1-2) is arranged at the end of the third first waveguide transmission channel (5-1c).

3. The forward millimeter-wave radar antenna according to claim 2, wherein The polarization conversion structure (5-1-2) is located at the middle position on the side of the first antenna radiation cavity (3-1); a first impedance matching structure (5-1-1) is arranged at the head end of the first first waveguide transmission channel (5-1a); a second impedance matching structure (3-2) is arranged at the position of the first antenna radiation cavity (3-1) close to the polarization conversion structure (5-1-2).

4. The forward millimeter-wave radar antenna according to claim 2, characterized in that, The first choke groove (3-5) extends along the second direction, and two of the first choke grooves (3-5) are symmetrically arranged on both sides of the first open horn (3-4) along the first direction.

5. A forward millimeter-wave radar antenna according to claim 1, characterized in that, The second waveguide transmission channel (5-2) includes a first second waveguide transmission channel (5-2a), a second second waveguide transmission channel (5-2b) and a third second waveguide transmission channel (5-2c) connected in sequence. The first second waveguide transmission channel (5-2a) and the third second waveguide transmission channel (5-2c) extend along the first direction, and the second second waveguide transmission channel (5-2b) extends along the second direction; A plurality of the sub-antenna structure units (4a) are distributed along the first direction, and the second antenna radiation cavity (4-1), the second slot radiation groove (4-2) and the second open horn (4-3) are arranged in sequence along the third direction; The second antenna radiation cavity (4-1) and the second open horn (4-3) extend along the second direction respectively, and a plurality of the second slot radiation grooves (4-2) are distributed along the second direction; The first direction, the second direction and the third direction are perpendicular to each other in pairs.

6. The forward millimeter-wave radar antenna according to claim 5, characterized in that, A third impedance matching structure (4-5) is arranged at the bottom of the second antenna radiation cavity (4-1), and a fourth impedance matching structure (5-2-1) is arranged at the head end of the first second waveguide transmission channel (5-2a).

7. A forward millimeter-wave radar antenna according to claim 5, characterized in that, The second choke groove (4-4) extends along the second direction, and two of the second choke grooves (4-4) are symmetrically arranged on both sides of the antenna structure array along the first direction.

8. The forward millimeter-wave radar antenna according to claim 5, characterized in that The splitter (7) includes a plurality of power branch paths (7-3) extending along the second direction. Each of the power branch paths (7-3) extends between two adjacent second antenna radiation cavities (4-1). A first branch path (7-6) and a second branch path (7-7) extending along both sides of the first direction are arranged at the end of each of the power branch paths (7-3). The first branch path (7-6) and the second branch path (7-7) are respectively connected to two adjacent second antenna radiation cavities (4-1).

9. The forward millimeter-wave radar antenna according to claim 8, characterized in that, A sixth impedance matching structure (7-2) is further provided between the end of the second waveguide transmission channel three (5-2c) and the splitter (7). A sub-channel (7-8) extending in the first direction is provided between the sixth impedance matching structure (7-2) and the two power branch paths (7-3), and a fifth impedance matching structure (7-1) is provided on the sub-channel (7-8).

10. A forward millimeter-wave radar antenna according to claim 8, characterized in that, On both sides of the end of the power branch path (7-3) along the third direction, a seventh impedance matching structure (7-4) and an eighth impedance matching structure (7-5) are respectively provided.

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