High-gain waveguide antenna

Abstract

The invention relates to a high-gain waveguide antenna. The antenna comprises a power divider and an antenna unit. The power divider comprises an H-plane waveguide extending along a first direction and an E-plane waveguide penetrating through the middle part of the H-plane waveguide and extending along a second direction; a corner cut structure is arranged at the joint of the E-plane waveguide and the H-plane waveguide; an input port is formed in one end, facing the second direction, of the H-plane waveguide, and the H-plane waveguide is provided with a first output port and a second output port; the antenna unit comprises a plurality of energy coupling units which are arranged at one end of the H-plane waveguide along the third direction and are distributed in a staggered manner along the first direction; the two corresponding energy coupling units are arranged in a central symmetry manner along the central axis of the third direction by taking the H-plane waveguide as the center; an antenna radiation port is formed in one end, far away from the H-plane waveguide, of each energy coupling unit in the third direction; according to the invention, low loss and high gain are realized, and the symmetry of an azimuth plane directional diagram can be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle-mounted radar, in particular to a high-gain waveguide antenna. BACKGROUND

[0002] The common feeding modes of waveguide antennas mainly include edge feeding and center feeding. The edge feeding structure is relatively simple, and is easy to process and implement, but the elevation plane pattern will deviate with the change of the working frequency, resulting in poor stability of the pattern. In comparison, the elevation plane pattern of the center feeding antenna will not deviate with the change of the frequency, and the pattern performance is more stable, but the structure is more complex. Usually, the implementation mode of the center feeding antenna is to convert the E-plane waveguide signal into an H-plane waveguide signal, and then feed it into the antenna radiation port. This structure needs to additionally set a polarization conversion structure, which not only increases the system complexity, but also easily causes the azimuth plane pattern to be asymmetric, thereby affecting the performance of the whole radar system. SUMMARY

[0003] Therefore, the present application provides a high-gain waveguide antenna which adopts a center feeding mode, can guarantee the symmetry of the azimuth plane pattern while realizing low loss and high gain, and has a simple structure, small size, no need for an additional polarization conversion structure, and is easy to process.

[0004] To solve the above technical problems, the present application provides a high-gain waveguide antenna, comprising a power divider and an antenna unit. The power divider comprises an H-plane waveguide extending along a first direction, and an E-plane waveguide extending along a second direction and penetrating the middle part of the H-plane waveguide; The E-plane waveguide and the H-plane waveguide are provided with a cut-angle structure at the connection part thereof, for realizing impedance matching and energy coupling; One end of the H-plane waveguide towards the second direction is provided with an input port, and the two ends of the H-plane waveguide along the first direction are respectively provided with a first output port and a second output port with opposite electromagnetic field phases; The antenna unit comprises a plurality of energy coupling units arranged at one end of the H-plane waveguide along a third direction and staggered along the first direction; Corresponding two energy coupling units are arranged in a central symmetry with the central axis of the H-plane waveguide along the third direction; Each energy coupling unit is provided with an antenna radiation port at one end thereof away from the H-plane waveguide along the third direction; The antenna unit is used for coupling the energy output by the power divider and radiating outward through the antenna radiation port; Wherein, the first direction, the second direction and the third direction are orthogonal to each other.

[0005] In an embodiment of the present application, the number of the energy coupling units is even.

[0006] In an embodiment of the present application, the antenna unit is provided with a radiation cavity on the side close to each of the antenna radiation ports in the third direction, and the radiation cavity extends along the second direction.

[0007] In an embodiment of the present application, the projection of the radiation cavity towards the antenna unit along the third direction covers each of the antenna radiation ports.

[0008] In an embodiment of the present application, the radiation cavity is provided with choke grooves on both sides along the second direction.

[0009] In an embodiment of the present application, the two choke grooves are mirror-symmetrically distributed about the symmetric cross-section of the radiation cavity along the first direction.

[0010] In an embodiment of the present application, the choke grooves extend along the first direction.

[0011] In an embodiment of the present application, the length of the choke grooves along the first direction is equal to the length of the radiation cavity along the first direction.

[0012] In an embodiment of the present application, each of the energy coupling units is provided with an impedance matching structure at the connection with the H-plane waveguide.

[0013] In an embodiment of the present application, the impedance matching structure is in the form of a step structure.

[0014] The above technical solution of the present application has the following advantages compared with the prior art: The high-gain waveguide antenna of the present application adopts the middle-feed structure of the E-plane waveguide penetrating the middle part of the H-plane waveguide, and the E-plane waveguide and the H-plane waveguide are provided with a cut-angle structure at the connection to realize transition coupling, thus eliminating the polarization conversion structure required by the traditional middle-feed antenna. This design not only simplifies the overall structure and reduces the insertion loss, but also effectively improves the energy transmission efficiency and the consistency of the feed. By respectively setting the first output port and the second output port with opposite electromagnetic field phases at both ends of the H-plane waveguide, and symmetrically arranging the energy coupling units on both sides of the central axis of the H-plane waveguide, each corresponding coupling unit is centrally symmetrically distributed with the central axis as the symmetric center, so that the field distribution of the radiation port is balanced and the phase is consistent, thereby realizing the high symmetry of the azimuth plane pattern and significantly improving the beam stability and angle measurement accuracy of the radar system.

[0015] The antenna unit of the present application is provided with a radiation cavity on the side close to the radiation port along the third direction, the radiation cavity extends along the E plane direction and is provided with choke grooves on both sides. The radiation cavity enlarges the effective radiation aperture and improves the radiation efficiency; the choke grooves can limit the spread of surface current and suppress the ineffective radiation, and the two work together to realize high gain and reduce the return loss. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings.

[0017] Figure 1 is a high-gain waveguide antenna structure schematic diagram of embodiment 1 of the present application.

[0018] Figure 2 is a power divider structure schematic diagram of embodiment 1 of the present application.

[0019] Figure 3 is an E plane waveguide and H plane waveguide structure schematic diagram of embodiment 1 of the present application.

[0020] Figure 4 is a high-gain waveguide antenna structure schematic diagram of embodiment 2 of the present application.

[0021] Figure 5 is a high-gain waveguide antenna structure schematic diagram of embodiment 3 of the present application.

[0022] Figure 6 is a return loss curve diagram of embodiment 3 of the present application.

[0023] Figure 7 is an azimuth plane direction and elevation plane direction diagram of embodiment 3 of the present application.

[0024] Explanation of the drawing marks of the specification: 1, power divider; 1-1, first output port; 1-2, input port; 1-3, second output port; 1-4, E plane waveguide; 1-5, cut angle structure; 1-6, H plane waveguide; 2, antenna unit; 2-1, right side energy coupling unit; 2-2, left side energy coupling unit; 2-3, first antenna radiation port; 3-1, impedance matching structure; 3-2, left side first energy coupling unit; 3-3, left side second energy coupling unit; 3-4, right side first energy coupling unit; 3-5, right side second energy coupling unit; 3-6, second antenna radiation port; 3-7, choke groove; 3-8, radiation cavity. DETAILED DESCRIPTION

[0025] The present application will be further described below in conjunction with the drawings and specific embodiments so that those skilled in the art can better understand and implement the present application, but the embodiments are not intended to limit the present application.

[0026] In the present application, if the direction (up, down, left, right, front and back) is described, it is only for the convenience of describing the technical solutions of the present application, and is not intended to indicate or imply that the indicated technical features must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application.

[0027] In the present application, the meaning of "several" is one or more, and the meaning of "multiple" is two or more. "Greater than", "less than", "more than" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In the description of the present application, 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 number of indicated technical features or the sequence of indicated technical features.

[0028] In the present application, unless otherwise explicitly limited, the words "set", "install", "connect" and the like should be broadly understood, for example, they can be directly connected, or indirectly connected through an intermediate medium; can be fixedly connected, or can be detachably connected, or can be integrally formed; can be mechanically connected, or can be electrically connected or capable of communicating with each other; can be the communication or interaction relationship between two elements or the interaction relationship between two elements. The skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solutions.

[0029] Embodiment 1 Referring to Figures 1 to 3 The high-gain waveguide antenna provided by the embodiment includes a power divider 1 and an antenna unit 2. The power divider 1 includes an H-plane waveguide 1-6 extending along a first direction, and an E-plane waveguide 1-4 extending along a second direction and passing through a middle part of the H-plane waveguide 1-6. The E-plane waveguide 1-4 and the H-plane waveguide 1-6 are provided with a cut-angle structure 1-5 at the connection part of the two, for realizing impedance matching and energy coupling. One end of the H-plane waveguide 1-6 towards the second direction is provided with an input port 1-2, and two ends of the H-plane waveguide 1-6 along the first direction are respectively provided with a first output port 1-1 and a second output port 1-3 with opposite electromagnetic field phases. The antenna unit 2 includes a right energy coupling unit 2-1 and a second left energy coupling unit 2-2 which are arranged at one end of the H-plane waveguide 1-6 along a third direction and staggered along the first direction. The right energy coupling unit 2-1 and the left energy coupling unit 2-2 are arranged in a center symmetry with respect to the central axis of the H-plane waveguide 1-6 along the third direction; The right energy coupling unit 2-1 and the left energy coupling unit 2-2 are respectively provided with a first antenna radiation port 2-3 away from one end of the H-plane waveguide 1-6 along the third direction; The antenna unit 2 is used for coupling the energy output by the power divider 1 and radiating outward through the first antenna radiation port 2-3; The first direction, the second direction and the third direction are orthogonal to each other.

[0030] It should be noted that the cut-angle structure 1-5 is located at the junction of the E-plane waveguide 1-4 penetrating into the H-plane waveguide 1-6, and is formed as an inclined surface or a stepped surface along the opening edge of the waveguide. The inclined surface can be a single continuous inclined surface, or can be in the form of multiple steps.

[0031] It can be understood that the energy is input by the E-plane waveguide 1-4, and is radiated outward through the power divider 1 and the antenna unit 2 (the right energy coupling unit 2-1 and the left energy coupling unit 2-2), and the first antenna radiation port 2-3 of the right energy coupling unit 2-1 and the left energy coupling unit 2-2 respectively.

[0032] In this embodiment, by adopting a center-fed waveguide structure, the energy is input by the E-plane waveguide 1-4 extending along the second direction, and the E-plane waveguide 1-4 penetrating into the middle of the H-plane waveguide 1-6 and the H-plane waveguide 1-6 extending along the first direction are connected through the cut-angle structure 1-5 to realize impedance transition and energy coupling. The energy injected by the E-plane waveguide 1-4 is distributed to both ends of the H-plane waveguide 1-6 through the power divider 1, and the first output port 1-1 and the second output port 1-3 with opposite phases are arranged at both ends of the H-plane waveguide 1-6 respectively, so as to form a phase-complementary field distribution on both sides of the central axis of the H-plane waveguide 1-6.

[0033] Embodiment 2 Referring to Figure 4 As shown in the figure, the high-gain waveguide antenna provided in this embodiment includes a power divider 1 and an antenna unit 2; The power divider 1 includes an H-plane waveguide 1-6 extending along a first direction, and an E-plane waveguide 1-4 penetrating into the middle of the H-plane waveguide 1-6 and extending along a second direction; The E-plane waveguide 1-4 and the H-plane waveguide 1-6 are provided with a cut-angle structure 1-5 at the junction of the two, for realizing impedance matching and energy coupling; The H-plane waveguide 1-6 is provided with an input port 1-2 at one end thereof facing the second direction, and first and second output ports 1-1 and 1-3 with opposite electromagnetic field phases are respectively arranged at two ends of the H-plane waveguide 1-6 along the first direction; The antenna unit 2 comprises left first and second energy coupling units 3-2 and 3-3, right first and second energy coupling units 3-4 and 3-5 which are arranged at one end of the H-plane waveguide 1-6 along the third direction and staggered along the first direction; The left first energy coupling unit 3-2 and the right second energy coupling unit 3-5 are arranged in central symmetry with respect to the central axis of the H-plane waveguide 1-6 along the third direction; and the left second energy coupling unit 3-3 and the right first energy coupling unit 3-4 are arranged in central symmetry with respect to the central axis of the H-plane waveguide 1-6 along the third direction; The left first energy coupling unit 3-2, the left second energy coupling unit 3-3, the right first energy coupling unit 3-4 and the right second energy coupling unit 3-5 are respectively provided with second antenna radiation ports 3-6 away from one end of the H-plane waveguide 1-6 along the third direction; The antenna unit 2 is configured to couple energy output by the power divider 1 and radiate outward through the second antenna radiation ports 3-6. The first direction, the second direction and the third direction are orthogonal to each other.

[0034] In this embodiment, the antenna unit 2 is expanded to a four-radiation-port antenna by the structure of embodiment 1, and energy is input by the E-plane waveguide 1-4, radiated outward through the power divider 1, the antenna unit 2 (the left first energy coupling unit 3-2, the left second energy coupling unit 3-3, the right first energy coupling unit 3-4 and the right second energy coupling unit 3-5) and the second antenna radiation ports 3-6 of each energy coupling unit.

[0035] This embodiment is expanded to a four-radiation-port structure, and the number of effective radiation ports is increased to increase the equivalent aperture, improve the directivity and gain; and the structure expansion can be modularly implemented in the manufacturing process, facilitating large-scale production.

[0036] Embodiment 3 Referring to Figure 5 As shown in the drawings, the embodiment is based on embodiment 2, and a radiation cavity 3-8 is arranged on one side of the antenna unit 2 along the third direction and close to each second antenna radiation port 3-6; The projection of the radiation cavity 3-8 along the third direction towards the antenna unit 2 covers each second antenna radiation port 3-6.

[0037] Further, the radiation cavity 3-8 is provided with choke grooves 3-7 on both sides along the second direction; the two choke grooves 3-7 are mirror-symmetrically distributed about the symmetric profile of the radiation cavity 3-8 along the first direction; the choke grooves 3-7 extend along the first direction.

[0038] Further, the length of the choke grooves 3-7 along the first direction is equal to the length of the radiation cavity 3-8 along the first direction.

[0039] Further, the left first energy coupling unit 3-2, the left second energy coupling unit 3-3, the right first energy coupling unit 3-4 and the right second energy coupling unit 3-5 are each provided with an impedance matching structure 3-1 at the connection with the H-plane waveguide 1-6, and the impedance matching structure 3-1 is in a stepped structure. The stepped impedance matching structure 3-1 improves the matching degree and transmission efficiency within the bandwidth.

[0040] By additionally providing the radiation cavity 3-8 and the choke grooves 3-7 on the four-radiation-port antenna, the radiation cavity 3-8 expands the equivalent aperture of the antenna in the azimuth plane, improves the radiation efficiency and main lobe gain; the choke grooves 3-7 suppress surface waves and invalid radiation, limit the lateral energy leakage, reduce the sidelobe and return loss, thereby improving the directivity and return characteristics of the antenna.

[0041] Referring to Figure 6 It can be seen that the four-radiation-port antenna in the embodiment has a return loss of less than -20 dB at 76-79 GHz, which can completely cover the main frequency band of the vehicle-mounted radar.

[0042] Referring to Figure 7 It can be seen that the four-radiation-port antenna in the embodiment has a gain of up to 16.2 dB, a sidelobe level of >20 dbc, and a good symmetry of the azimuth plane pattern (azimuth plane direction and elevation plane direction).

[0043] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A high-gain waveguide antenna, characterized in that, Includes power divider and antenna unit; The power divider includes an H-plane waveguide extending along a first direction and an E-plane waveguide passing through the middle of the H-plane waveguide and extending along a second direction. The E-plane waveguide and the H-plane waveguide have a chamfered structure at their connection point to achieve impedance matching and energy coupling. An input port is provided at one end of the H-plane waveguide facing the second direction, and a first output port and a second output port with opposite electromagnetic field phases are respectively provided at both ends of the H-plane waveguide along the first direction. The antenna unit includes a plurality of energy coupling units disposed at one end of the H-plane waveguide along the third direction and staggered along the first direction; The two corresponding energy coupling units are arranged in a centrally symmetrical manner with respect to the H-plane waveguide along the central axis of the third direction. Each of the energy coupling units is provided with an antenna radiation port at the end away from the H-plane waveguide along the third direction; The antenna unit is used to couple the energy output by the power divider and radiate it outward through the antenna radiating port; The first direction, the second direction, and the third direction are all orthogonal to each other.

2. A high-gain waveguide antenna according to claim 1, characterized in that, The number of energy coupling units is even.

3. A high-gain waveguide antenna according to claim 1, characterized in that, The antenna unit has a radiation cavity on the side facing the third direction and close to each of the antenna radiation ports, and the radiation cavity extends along the second direction.

4. A high-gain waveguide antenna according to claim 3, characterized in that, The projection of the radiating cavity toward the antenna element along the third direction covers each of the antenna radiating ports.

5. A high-gain waveguide antenna according to claim 3, characterized in that, The radiation cavity is provided with choke grooves on both sides along the second direction.

6. A high-gain waveguide antenna according to claim 5, characterized in that, The two choke slots are mirror-symmetrically distributed with respect to the symmetrical cross-section of the radiation cavity along the first direction.

7. A high-gain waveguide antenna according to claim 5, characterized in that, The choke groove extends along the first direction.

8. A high-gain waveguide antenna according to claim 7, characterized in that, The length of the choke groove along the first direction is equal to the length of the radiation cavity along the first direction.

9. A high-gain waveguide antenna according to claim 1, characterized in that, An impedance matching structure is provided at the connection between each energy coupling unit and the H-plane waveguide.

10. A high-gain waveguide antenna according to claim 9, characterized in that, The impedance matching structure has a stepped structure.

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