Waveguide wide-beam antenna
By designing an interleaved rectangular waveguide antenna structure and an artificial surface plasmon structure, the problems of high fabrication difficulty and high loss of traditional waveguide antennas were solved, enabling low-cost, high-performance millimeter-wave radar for large-angle detection.
Patent Information
- Application Number
- CN202511417203.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2025-11-21
AI Technical Summary
Traditional waveguide antennas are difficult to process and assemble in the millimeter-wave band, have high costs, large transmission losses, and small power capacity, and cannot meet the requirements for large-angle detection.
Design a waveguide wide-beam antenna, which uses a first metal layer and a second metal layer to form a rectangular waveguide transmission line. The radiation port is set as a staggered distribution of short rectangular ports. Artificial surface plasmon structures are provided on the sidewalls and the outer side of the waveguide port. Matching stubs are used for impedance matching. The material is made of copper plate or plastic molded and fixed by screws or welding.
It reduces manufacturing precision and processing costs, achieves wide-angle detection capability, and features low loss, high power capacity, and large bandwidth, making it suitable for millimeter-wave radar.
Smart Images
Figure CN120999293A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of communication devices, and particularly relates to a waveguide wide-beam antenna. BACKGROUND
[0002] In recent years, people have higher and higher requirements for the wide-angle detection of millimeter wave radars, and the waveguide wide-beam antenna in the millimeter wave frequency band can meet the requirements. Especially in higher-order intelligent driving systems, the millimeter wave radar is favored due to the advantages of multi-channel and all-weather and high performance.
[0003] The traditional waveguide antenna has great difficulty in processing and assembling in the millimeter wave frequency band, which will increase the cost, is not conducive to wide application, has large transmission loss, small power capacity, and cannot meet the wide-angle detection of radars, so a waveguide wide-beam antenna is urgently needed to solve the above problems. SUMMARY
[0004] In view of the problems in the above background art, the purpose of the present application is to provide a waveguide wide-beam antenna.
[0005] To achieve the above technical purpose, the technical scheme adopted by the present application is as follows: A waveguide wide-beam antenna, comprising a first metal layer and a second metal layer; The first metal layer is provided with a radiation port, the front surface of the second metal layer is provided with a horizontal waveguide channel, the end of the horizontal waveguide channel is opposite to the radiation port, the second metal layer is provided with a vertical waveguide channel at the beginning of the horizontal waveguide channel, the back surface of the second metal layer is provided with a first waveguide port, the first waveguide port is in communication with the vertical waveguide channel, and the horizontal waveguide channel provided in the first metal layer and the second metal layer is stacked up and down to form a rectangular waveguide transmission line; The radiation port comprises a first short rectangular port, a second short rectangular port, a third short rectangular port, a fourth short rectangular port and a fifth short rectangular port, and the first short rectangular port, the second short rectangular port, the third short rectangular port, the fourth short rectangular port and the fifth short rectangular port are sequentially and alternately distributed along the axis AA' of the signal transmission direction of the horizontal waveguide channel.
[0006] Further limited, the vertical projections of the first short rectangular port, the second short rectangular port, the third short rectangular port, the fourth short rectangular port and the fifth short rectangular port are located in the horizontal waveguide channel, the number of the radiation ports can also be other numbers except five, the opening areas of the first short rectangular port, the second short rectangular port, the third short rectangular port, the fourth short rectangular port and the fifth short rectangular port are sequentially reduced, and the distances of the adjacent rectangular ports along the axis AA' can be equal or unequal.
[0007] Further limited, the horizontal waveguide channel is arranged in a straight structure, and can also be arranged in a curved structure, the horizontal waveguide channel and the first metal layer form a complete rectangular waveguide transmission line, and the first metal layer and the second metal layer are in complete electrical connection, or partial electrical connection, or have a gap.
[0008] Further limited, the horizontal waveguide channel is arranged in a straight structure, and can also be arranged in a curved structure, the horizontal waveguide channel and the first metal layer form a complete rectangular waveguide transmission line, and the first metal layer and the second metal layer are in complete electrical connection, or partial electrical connection, or have a gap.
[0009] Further limited, the first artificial surface plasmon structure includes a plurality of etched grooves arranged on the outer side of the side wall, and an etched protrusion is arranged between two adjacent etched grooves, the artificial surface plasmon structure is realized through the periodic or aperiodic etched grooves, and the etched protrusion between the two adjacent etched grooves is electrically connected to the outer side of the side wall of the horizontal waveguide channel.
[0010] Further limited, the height of the protrusion perpendicular to the horizontal plane of the second metal layer is equal to or different from the height of the side wall of the horizontal waveguide channel, and the width and the depth of the adjacent etched grooves are equal or different.
[0011] Further limited, the shape of the protrusion and the etched groove is rectangular, elliptical, semicircular or triangular.
[0012] Further limited, the outer side of the first waveguide port is provided with a periodic or aperiodic second artificial surface plasmon structure, the first waveguide port is provided with a metal fence outside the second artificial surface plasmon structure, the second artificial surface plasmon structure includes a protrusion and a groove, the height of the protrusion is equal to or different from the height of the side wall of the first waveguide port, and the shape of the groove is the same or different.
[0013] Further limited, the junction between the start end of the horizontal waveguide channel and the vertical waveguide channel is provided with a matching stub, the matching stub is located on the bottom surface of the horizontal waveguide channel and is electrically connected to the bottom surface, the start end of the matching stub extends to the inner side of the vertical waveguide channel, and the end thereof is arranged in a horn or rectangular structure.
[0014] Further limited, the thickness of the first metal layer is 0.1-1 mm, the first metal layer is punched or etched from a copper plate, or is plastic formed and then surface metallized, or is processed by a CNC process, the second metal layer is processed by a CNC process, or is plastic formed and then surface metallized, or is a surface copper layer of a circuit board, and the first metal layer and the second metal layer are fixedly connected through locking screws, riveting or welding.
[0015] The present application has the following beneficial effects: 1. The waveguide wide-beam antenna of the present application can effectively reduce manufacturing precision, reduce processing degree, save processing cost, and has large angle detection capability in the azimuth direction, which is very suitable for millimeter wave angle radar application.
[0016] 2. The waveguide wide-beam antenna of the present application is mainly used in the millimeter wave region (30GHz-300GHz), but the present application also has advantages in frequencies higher than 300GHz or lower than 30GHz, and has low loss, high power capacity and large bandwidth application scenarios, meets the requirements of large tolerance redundancy and low cost, and has the requirement of wide-beam in the azimuth direction. BRIEF DESCRIPTION OF DRAWINGS
[0017] The present application can be further illustrated by the non-limiting examples shown in the accompanying drawings; Figure 1 is a schematic diagram of the overall structure of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 2 is a front view and a rear view of a first metal layer of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 3 is a front view and a rear view of a second metal layer of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 4 is a front perspective view of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 5 is a schematic diagram of the structure of a second metal layer of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 6 is a schematic diagram of a matching stub variant of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 7 is a schematic diagram of a four-transmitting and four-receiving array antenna structure composed of unit antennas of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 8 is a reflection coefficient of a waveguide wide-beam antenna according to an embodiment of the present application; Figure 9 is a normalized radiation pattern of a waveguide wide-beam antenna according to an embodiment of the present application; The main component symbols are explained as follows: first metal layer 1, second metal layer 2; radiation port 3, first short rectangular port 301, second short rectangular port 302, third short rectangular port 303, fourth short rectangular port 304, fifth short rectangular port 305; horizontal waveguide channel 4, vertical waveguide channel 5, first waveguide port 6; matching stub 7, matching stub end 71, matching stub middle section 72, matching stub start end 73; Side wall 8, etching protrusion 9, etching groove 10, metal fence 11, protrusion 12, groove 13. DETAILED DESCRIPTION
[0018] In order for those skilled in the art to better understand the present application, the technical solutions of the present application are further described below in conjunction with the drawings and examples.
[0019] A waveguide wide-beam antenna comprises a first metal layer 1 and a second metal layer 2. The first metal layer 1 and the second metal layer 2 are arranged in a top-down stack, and the back surface of the first metal layer 1 and the front surface of the second metal layer 2 have a gap, or are partially electrically connected, or are designed to be fully electrically connected.
[0020] The first metal layer 1 is provided with a radiation port 3, the front surface of the second metal layer 2 is provided with a horizontal waveguide channel 4, and the back surface is provided with a first waveguide port 6. The first waveguide port 6 is connected to the beginning end of the horizontal waveguide channel 4 through a vertical waveguide channel 5 penetrating the second metal layer 2. The horizontal waveguide channel 4 arranged in the first metal layer 1 and the second metal layer 2 forms a rectangular waveguide transmission line through the top-down stack.
[0021] The radiation port 3 in the first metal layer 1 comprises five first short rectangular ports 301, a second short rectangular port 302, a third short rectangular port 303, a fourth short rectangular port 304, and a fifth short rectangular port 305, and the five short rectangular ports are sequentially staggered along the axis AA' of the signal transmission direction of the horizontal waveguide channel 4.
[0022] Preferably, the vertical projections of the five short rectangular ports are located in the horizontal waveguide channel 4. In addition, the number of radiation ports 3 can also be other numbers besides five. The opening areas of the first short rectangular port 301, the second short rectangular port 302, the third short rectangular port 303, the fourth short rectangular port 304, and the fifth short rectangular port 305 are sequentially decreasing, and the distances between adjacent rectangular ports along the axis AA' can be equal or unequal.
[0023] The radiation port 3 of the first metal layer 1 is a transmission port for receiving or transmitting electromagnetic signals.
[0024] The thickness of the first metal layer 1 is preferably 0.1-1 mm.
[0025] The back surface of the second metal layer 2 is provided with a horizontal waveguide channel 4, the end of the horizontal waveguide channel 4 is opposite to the radiation port 3 of the first metal layer 1, and the beginning end of the horizontal waveguide channel 4 is connected to the first waveguide port 6 through a vertical channel penetrating the second metal layer 2.
[0026] The horizontal waveguide channel 4 can be straight or curved.
[0027] Preferably, the horizontal waveguide channel 4 and the first metal layer 1 form a complete rectangular waveguide transmission line, and the first metal layer 1 and the second metal layer 2 can be completely electrically connected, or partially electrically connected, or have a gap.
[0028] Preferably, the horizontal waveguide channel 4, whose side wall 8 is located outside the horizontal waveguide channel 4, is provided with a periodic or non-periodic first artificial surface plasmon structure.
[0029] Preferably, the first artificial surface plasmon structure is realized by periodically or non-periodically etching grooves 10 outside the side wall 8 of the horizontal waveguide, and the etched protrusions 9 between adjacent grooves are electrically connected to the outside of the side wall 8 of the horizontal waveguide channel 4.
[0030] Preferably, the height of the protrusions 9 perpendicular to the horizontal plane of the second metal layer 2 can be equal to or not equal to the height of the side wall 8 of the horizontal waveguide channel 4, and the width and depth of adjacent grooves can be equal or not equal.
[0031] Preferably, the shape of the protrusions 9 and the grooves can be rectangular, oval, semicircular, triangular, etc.
[0032] Due to the existence of the artificial surface plasmon structure, when there is a gap between the first metal layer 1 and the second metal layer 2, the electromagnetic energy transmitted along the horizontal waveguide channel 4 can be bound around the side wall 8 of the horizontal waveguide channel 4 and transmitted in the transmission direction, thereby ensuring that there is a large tolerance redundancy when the first metal layer 1 and the second metal layer 2 are assembled.
[0033] The back of the second metal layer 2 is provided with a first waveguide port 6, and a periodic or non-periodic second artificial surface plasmon structure is also provided around the first waveguide port 6. The first waveguide port 6 is provided with a metal fence 11 outside the second artificial surface plasmon structure, and the protrusions 12 of the second artificial surface plasmon structure are partially electrically connected to the side wall 8 of the first waveguide port 6, and their height can be equal to or not equal to the height of the side wall 8 of the first waveguide port 6, and the shapes of adjacent grooves 13 can be the same or different.
[0034] Preferably, the first waveguide port 6 is a structure for connecting a waveguide wide-beam antenna and a PCB. If no artificial surface plasmon structure is provided around the first waveguide port 6, electromagnetic energy will leak if there is a gap between them. However, after the artificial surface plasmon structure is provided around the first waveguide port 6, the leaked electromagnetic energy caused by the gap can be bound around the first waveguide port 6, preventing the leakage of electromagnetic energy.
[0035] Preferably, a matching branch 7 is further arranged at the junction of the beginning of the horizontal waveguide channel 4 and the vertical waveguide channel 5, the matching branch 7 is located at the bottom surface of the horizontal waveguide channel 4 and is electrically connected with the bottom surface, the beginning of the matching branch 7 extends to the inner side of the vertical waveguide channel 5, and the end is in the shape of a horn or a rectangle.
[0036] Preferably, the waveguide wide-beam antenna of the present application can also be arranged in an array form, such as a four-transmitting and four-receiving array or an eight-transmitting and eight-receiving array. The array antenna composed of the gap waveguide wide-beam antenna is also arranged in a two-layer structure, i.e., the first metal layer 1 and the second metal layer 2, and the first metal layer 1 and the second metal layer 2 are arranged in a top-to-bottom manner.
[0037] Preferably, the material characteristics and assembly method of the first metal layer 1 and the second metal layer 2 are as follows: the first metal layer 1 can be punched or etched from a copper plate, or can be plastic formed and then surface metallized, or can be a CNC process; the second metal layer 2 can be a CNC process, or can be plastic formed and then surface metallized, or can be a surface copper layer of a circuit board. The first metal layer 1 and the second metal layer 2 can be fixed by a locking screw, riveting or welding process. Embodiment
[0038] In the present embodiment one, referring to Figure 1 , the waveguide wide-beam antenna structure of the present embodiment one includes two parts, i.e., the first metal layer 1 and the second metal layer 2.
[0039] As shown in Figure 2 , the front view and the back view of the first metal layer in the present embodiment one are shown, wherein Figure 2 (a) is the front view of the first metal layer 1, Figure 2 (b) is the back view of the first metal layer 1, the first metal layer 1 is provided with a radiation port 3; the radiation port 3 includes five first short rectangular ports 301, a second short rectangular port 302, a third short rectangular port 303, a fourth short rectangular port 304 and a fifth short rectangular port 305, and the five short rectangular ports form the ports of the antenna for radiating / receiving signals.
[0040] In order to realize a wide beam, the thickness of the first metal layer 1 is as thin as possible, and the ideal thickness size is between 0.1-1mm. The five short rectangular ports are distributed in an alternating manner on both sides of the axis AA', and the vertical projection thereof falls within the end of the horizontal waveguide channel 4. The length of each short rectangular port is theoretically, which is the air wavelength, and the interval between adjacent short rectangular ports is approximately, wherein is the waveguide wavelength. Considering the influence of mutual coupling between the antenna units, the size of each short rectangular port will be different.
[0041] As shown in Figure 3 , the front view and the back view of the second metal layer 2 in the present embodiment one are shown, wherein Figure 3 (a) is the front view of the second metal layer 2,Figure 3 (b) is a back view of the second metal layer 2, the front side of the second metal layer 2 is provided with horizontal waveguide channels 4 whose end vertical projections are directly opposite the radiation ports 3 of the first metal layer 1, and the back side of the second metal layer 2 is provided with first waveguide ports 6, wherein the first waveguide ports 6 are connected to the beginning of the horizontal waveguide channels 4 through vertical waveguide channels 5 that pass through the second metal layer 2. The first metal layer 1 and the horizontal waveguide channels 4 provided in the second metal layer 2 form a rectangular waveguide transmission line.
[0042] The number of radiation ports 3 can be one, two, three, four, six, etc. in addition to the five in Embodiment One, and the odd-numbered short rectangular ports in the radiation ports 3 are located on the same side of the axis, and the even-numbered short rectangular ports are located on the other side of the axis AA'. In addition, the odd-numbered and even-numbered short rectangular ports are alternately located on both sides of the axis AA' in the direction of the axis. In addition, because a wide beam is to be achieved, the sizes of all the short rectangular ports and the distances from the axis AA' are not uniform.
[0043] The horizontal waveguide channels 4 and the first metal layer 1 form a complete rectangular waveguide transmission line, and the first metal layer 1 and the second metal layer 2 can be completely electrically connected, or partially electrically connected, or there can be a gap. The horizontal waveguide channels 4 can be straight or curved.
[0044] In addition to achieving a wide beam, in order to reduce assembly tolerance and cost, a periodic or non-periodic artificial surface plasmon structure is provided on the outside of the side wall 8 of the horizontal waveguide channel 4 perpendicular to the horizontal plane of the second metal layer 2. This structure can confine the transmitted electromagnetic energy in the horizontal waveguide channel 4 when there is a gap between the first metal layer 1 and the second metal layer 2, and make the electromagnetic signal transmit in the desired direction.
[0045] The artificial surface plasmon structure is realized by etching periodic or non-periodic etching grooves 10 on the outside of the side wall 8 of the horizontal waveguide, and the etching protrusions 9 between adjacent etching grooves 10 are electrically connected to the outside of the side wall 8 of the horizontal waveguide channel 4.
[0046] The height of the etching protrusions 9 perpendicular to the horizontal plane of the second metal layer 2 can be equal to or not equal to the height of the side wall 8 of the horizontal waveguide channel 4; the width and depth of adjacent etching grooves 10 can be equal or not equal.
[0047] The first waveguide ports 6 are also provided on the back side of the second metal layer 2, and a periodic or non-periodic artificial surface plasmon structure is also provided around the first waveguide ports 6. The protrusions 13 of this artificial surface plasmon structure are electrically connected to the side wall 8 of the first waveguide ports 6, and their height can be equal to or not equal to the height of the side wall 8 of the first waveguide ports 6, and the shapes of adjacent grooves 13 can be the same or different.
[0048] The shape of the protrusions 13 and the grooves 13 contained in the artificial surface plasmon structure arranged on the outer side of the horizontal waveguide channel 4 side wall 8 or the outer side of the first waveguide port 6 can be rectangular, oval, semicircular, triangular, etc.
[0049] In order to improve the performance of the antenna in embodiment one, a matching branch 7 is arranged at the junction of the beginning end of the horizontal waveguide channel 4 and the vertical waveguide channel 5, wherein: the matching branch 7 is located on the bottom surface of the horizontal waveguide channel 4 and is electrically connected with the bottom surface; the beginning end of the matching branch 7 extends to the inner side of the vertical waveguide channel 5, and the end is in the shape of a horn or a rectangle. The waveguide wide-beam antenna of the present application can also be arranged in an array form, such as a four-transmitting and four-receiving array (for example, Figure 7 ) and the like, and the array antenna composed of the waveguide wide-beam antenna is also arranged in a two-layer structure, i.e., the first metal layer 1 and the second metal layer 2.
[0050] Figure 4 The front perspective view of the waveguide wide-beam antenna of embodiment one is shown. Embodiment
[0051] As Figure 5 The rear view and the front view of the second metal layer 2 of embodiment two are shown, wherein Figure 5 (a) is the front view of the second metal layer 2, Figure 5 (b) is the rear view of the second metal layer 2.
[0052] Compared with embodiment one, embodiment two is also a two-layer structure, i.e., the first metal layer 1 and the second metal layer 2, wherein the first metal layer 1 in embodiment two is exactly the same as the first metal layer 1 in embodiment one, and the difference is that the second metal layer 2 in embodiment two is different from the second metal layer 2 in embodiment one, specifically, the vertical waveguide channel 5 in embodiment one is a double-ridge structure, while the structure of the vertical waveguide channel 5 in embodiment two is changed from the double-ridge structure to a rectangular structure, and the beginning end of the matching branch 7 in embodiment two extends to the inner side of the rectangular vertical waveguide channel 5.
[0053] The assembly and working principle of the first metal layer 1 and the second metal layer 2 of embodiment two are consistent with those of embodiment one. Embodiment
[0054] As Figure 6For the matching branch 7 structure diagram of the third embodiment, the matching branch 7 includes a matching branch end 71, a matching branch middle section 72, and a matching branch start end 73. Different from the matching branch 7 in the first and second embodiments, the matching branch end 71 in the third embodiment is in a horn shape, while the matching branch end 71 in the first and second embodiments is in a rectangular shape. The matching branch 7 in the third embodiment can completely replace the matching branch 7 in the first and second embodiments to achieve good impedance matching and thus excellent antenna performance.
[0055] The working frequency band applied to the vehicle-mounted millimeter wave radar is generally 76-81 GHz, while in Figure 8 The simulation reflection coefficient diagram of the waveguide wide-beam antenna of the first embodiment is given, from which Figure 8 It can be obtained that the reflection coefficient bandwidth with-10 dB as the reference is from 74.5-81.8 GHz, achieving a working bandwidth of 7.3 GHz. Moreover, the working bandwidth is much larger than the working bandwidth 76-81 GHz of the millimeter wave radar, which leaves bandwidth redundancy for the frequency deviation caused by the tolerance of actual processing and manufacturing.
[0056] Figure 9 The antenna normalized radiation pattern of the first embodiment is given. It can be seen that the sidelobe level of the antenna radiation pattern in the elevation direction is lower than-17 dB, which provides strong anti-interference capability for the millimeter wave radar in detecting the target in the elevation direction. In the azimuth direction, the 3dB beam width is greater than 120°, reaching 133°, which is very suitable for the detection of the millimeter wave radar in a large angle range.
[0057] The material characteristics of the first metal layer 1 and the second metal layer 2 of the three embodiments given above are that the first metal layer 1 can be punched or etched from a copper plate, or plastic formed and then surface metallized, or CNC process; the second metal layer 2 can be CNC process, or plastic formed and then surface metallized, or a metal layer on the surface of a circuit board; the first metal layer 1 and the second metal layer 2 can be fixed by screw locking, riveting or welding process.
[0058] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.
Claims
1. A waveguide wide-beam antenna, characterized in that: It includes a first metal layer (1) and a second metal layer (2); The first metal layer (1) is provided with a radiation port (3), the front side of the second metal layer (2) is provided with a horizontal waveguide channel (4), the end of the horizontal waveguide channel (4) is directly opposite the radiation port (3), the second metal layer (2) is provided with a vertical waveguide channel (5) at the beginning of the horizontal waveguide channel (4), the back side of the second metal layer (2) is provided with a first waveguide port (6), the first waveguide port (6) is connected to the vertical waveguide channel (5), and the horizontal waveguide channel (4) provided in the first metal layer (1) and the second metal layer (2) are stacked to form a rectangular waveguide transmission line; The radiation port (3) includes a first short rectangular port (301), a second short rectangular port (302), a third short rectangular port (303), a fourth short rectangular port (304), and a fifth short rectangular port (305). The first short rectangular port (301), the second short rectangular port (302), the third short rectangular port (303), the fourth short rectangular port (304), and the fifth short rectangular port (305) are sequentially and intersectingly distributed along the axis AA' of the signal transmission direction of the horizontal waveguide channel (4).
2. The waveguide wide-beam antenna according to claim 1, characterized in that: The vertical projections of the first short rectangular opening (301), the second short rectangular opening (302), the third short rectangular opening (303), the fourth short rectangular opening (304), and the fifth short rectangular opening (305) are located within the horizontal waveguide channel (4). The number of radiation openings (3) can also be any number other than five. The opening areas of the first short rectangular opening (301), the second short rectangular opening (302), the third short rectangular opening (303), the fourth short rectangular opening (304), and the fifth short rectangular opening (305) decrease sequentially, and the spacing between adjacent rectangular openings along the axis AA' can be equal or unequal.
3. A waveguide wide-beam antenna according to claim 2, characterized in that: The horizontal waveguide channel (4) is arranged in a straight structure. The horizontal waveguide channel (4) can also be arranged in a curved structure. The horizontal waveguide channel (4) and the first metal layer (1) form a complete rectangular waveguide transmission line. The first metal layer (1) and the second metal layer (2) are completely electrically connected, partially electrically connected, or have a gap.
4. A waveguide wide-beam antenna according to claim 3, characterized in that: The horizontal waveguide channel (4) has a sidewall (8) on its outer side, and the sidewall (8) has a periodic or non-periodic first artificial surface plasmon structure on its outer side.
5. A waveguide wide-beam antenna according to claim 4, characterized in that: The first artificial surface plasmon structure includes a plurality of etched grooves (10) disposed on the outside of the sidewall (8), wherein an etched protrusion (9) is provided between two adjacent etched grooves (10), and the artificial surface plasmon structure is realized by periodic or non-periodic etched grooves (10), and the etched protrusion (9) between two adjacent etched grooves (10) is electrically connected to the outside of the sidewall (8) of the horizontal waveguide channel (4).
6. A waveguide wide-beam antenna according to claim 5, characterized in that: The etched protrusion (9) is perpendicular to the horizontal plane of the second metal layer (2), and may be at the same height as the sidewall (8) of the horizontal waveguide channel (4), or may not be at the same height. The width and depth of the adjacent etched grooves (10) may be equal or unequal.
7. A waveguide wide-beam antenna according to claim 6, characterized in that: The etched protrusions (9) and etched grooves (10) are rectangular, elliptical, semi-circular, and triangular in shape.
8. A waveguide wide-beam antenna according to claim 7, characterized in that: The outer periphery of the first waveguide port (6) is provided with a periodic or non-periodic second artificial surface plasmon structure. The first waveguide port (6) is provided with a metal fence (11) on the outside of the second artificial surface plasmon structure. The second artificial surface plasmon structure includes a protrusion (12) and a groove (13). The protrusion (12) is electrically connected to the side wall of the first waveguide port (6). Its height is equal to or different from the side wall of the first waveguide port (6). The shape of the groove (13) can be the same or different.
9. A waveguide wide-beam antenna according to claim 8, characterized in that: A matching stub (7) is provided at the junction of the beginning of the horizontal waveguide channel (4) and the vertical waveguide channel (5). The matching stub (7) is located on the bottom surface of the horizontal waveguide channel (4) and is electrically connected to the bottom surface. The beginning of the matching stub (7) extends to the inner side of the vertical waveguide channel (5), and its end is set in a trumpet-shaped or rectangular structure.
10. A waveguide wide-beam antenna according to claim 9, characterized in that: The thickness of the first metal layer (1) is 0.1 to 1 mm. The first metal layer (1) is made by stamping or etching copper plate, or by metallizing the surface after plastic molding, or by CNC machining. The second metal layer (2) is made by CNC machining, or by metallizing the surface after plastic molding, or by copper layer on the surface of a circuit board. The first metal layer (1) and the second metal layer (2) are fixedly connected by screws, riveting or welding.