Low-sidelobe gap waveguide slot antenna based on artificial surface plasmon

Abstract

The invention discloses a low-sidelobe gap waveguide slot antenna based on artificial surface plasmon, which comprises a first metal layer and a second metal layer which are oppositely stacked, and a gap is arranged on the joint surface of the two metal layers. One end of the antenna is electrically connected to a first waveguide port having a receiving / transmitting signal, and the other end is connected to the radiation opening as a radiation / receiving end of a radio frequency signal. The antenna comprises a horizontal waveguide channel and a vertical waveguide channel, and a matching branch knot is arranged in the horizontal waveguide channel. And an artificial surface plasmon structure is arranged on the outer side of the side wall of the horizontal waveguide channel. By arranging the artificial surface plasmon structure, when the gap exists between the first metal layer and the second metal layer, electromagnetic energy is bound around the artificial surface plasmon, and therefore it is guaranteed that the electromagnetic energy can be completely transmitted in the expected direction. The antenna scheme provided by the invention has great advantages on assembly tolerance redundancy and cost control during mass production.

Description

Technical Field

[0001] The present invention belongs to the technical field, and in particular relates to a low sidelobe gap waveguide slot antenna based on artificial surface plasmons. Background Art

[0002] In recent years, people have increasingly higher requirements for information transmission capacity and quality, and waveguide antennas in the millimeter wave band can meet this requirement. Especially in higher-level intelligent driving systems, 4D millimeter wave radars are favored due to their multi-channel, all-weather, and high-performance advantages.

[0003] However, traditional waveguide antennas are difficult to process and assemble, which increases costs and fails to meet requirements in terms of process, power capacity, cost, and anti-interference, making them unsuitable for wide-ranging applications. Summary of the invention

[0004] In view of the problems raised by the above background technology, the object of the present invention is to provide a low sidelobe gap waveguide slot antenna based on artificial surface plasmon.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A low sidelobe gap waveguide slot antenna based on artificial surface plasmon, characterized by comprising a first metal layer and a second metal layer;

[0007] The first metal layer is provided with a radiation opening and a plurality of long rectangular openings for suppressing surface waves; the second metal layer is provided with a horizontal waveguide channel on the surface facing the first metal layer; the first metal layer and the horizontal waveguide channel arranged in the second metal layer constitute a rectangular waveguide transmission line; the vertical projection of the end of the horizontal waveguide channel is directly opposite to the radiation opening of the first metal layer; the second metal layer is provided with a vertical waveguide channel at the starting end of the horizontal waveguide channel; the back side of the second metal layer is provided with a first waveguide port, and the first waveguide port is connected to the starting end of the horizontal waveguide channel through the vertical waveguide channel.

[0008] It is further defined that the radiation opening includes a first short rectangular opening, a second short rectangular opening, a third short rectangular opening, a fourth short rectangular opening and a fifth short rectangular opening, wherein the first short rectangular opening, the second short rectangular opening, the third short rectangular opening, the fourth short rectangular opening and the fifth short rectangular opening are cross-symmetrically distributed along the axis of the signal transmission direction of the horizontal waveguide channel, and the vertical projections of the five short rectangular openings are located in the horizontal waveguide channel;

[0009] The length and width of the first short rectangular opening are completely consistent with those of the fifth short rectangular opening, and the first short rectangular opening and the fifth short rectangular opening are both located on the same side of the axis of the horizontal waveguide channel signal transmission direction, and are at equal distances from the axis;

[0010] The length and width of the second short rectangular opening are completely consistent with those of the fourth short rectangular opening, and the second short rectangular opening and the fourth short rectangular opening are both located on the same side of the axis of the signal transmission direction of the horizontal waveguide channel, and are at equal distances from the axis; the sizes of the second short rectangular opening and the fourth short rectangular opening are inconsistent with those of the first short rectangular opening and the fifth short rectangular opening, and they are respectively located on different sides of the axis and at unequal distances from the axis;

[0011] The length and width of the third short rectangular opening are different from those of the first short rectangular opening, the second short rectangular opening, the fourth short rectangular opening and the fifth short rectangular opening, and the third short rectangular opening is located on the same side of the axis of the signal transmission direction of the horizontal waveguide channel as the first short rectangular opening and the fifth short rectangular opening, but its distance from the axis is different.

[0012] It is further defined that the number of the radiation openings is one or more, and the odd-numbered short rectangular openings in the radiation openings are located on the same side of the axis, the even-numbered short rectangular openings are located on the other side of the axis, and the odd-numbered short rectangular openings and the even-numbered short rectangular openings are cross-symmetrically distributed along the axis; the sizes of the first short rectangular opening, the second short rectangular opening, the third short rectangular opening, the fourth short rectangular opening and the fifth short rectangular opening can also be completely consistent, and the distances from the axis are also the same.

[0013] It is further defined that the long rectangular openings are symmetrically arranged on both sides of the radiation opening along the axis, the distances between the long rectangular openings on both sides and the axis are equal or unequal, the long rectangular openings on both sides can be arranged in equal lengths or unequal lengths, the number of the long rectangular openings arranged on both sides of the axis is one or more, and the vertical projection of the long rectangular opening cannot be located in the horizontal waveguide channel.

[0014] It is further defined that the horizontal waveguide channel is arranged in a curved structure, and may also be arranged in a straight 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 completely electrically connected, or partially electrically connected, or there is a gap.

[0015] It is further defined that the first waveguide port and the horizontal waveguide channel are provided with an artificial surface plasmon structure on the outer side wall perpendicular to the second metal layer, and the artificial surface plasmon structure includes a plurality of grooves arranged on the outer side wall of the horizontal waveguide channel, and a protrusion is provided between two adjacent grooves; the shape of the protrusion and the groove is rectangular, elliptical, semicircular or triangular.

[0016] It is further defined that the horizontal waveguide channel is provided with a matching branch at the junction with the vertical waveguide channel, the matching branch is arranged on the bottom side of the horizontal waveguide channel and is electrically connected to the bottom side of the horizontal waveguide channel, the starting end of the matching branch extends into the vertical waveguide channel or to the edge of the vertical waveguide channel, and the end thereof is arranged in a trumpet-shaped structure.

[0017] It is further defined that the second metal layer is symmetrically provided with metal strips on both sides of the radiation opening, the metal strips are arranged in a rectangular structure, and the metal strips may also be provided with corrugated grooves on the side wall close to the horizontal waveguide channel, and a distance of at least 0.3 mm is maintained between the metal strips and the outer side wall of the horizontal waveguide channel.

[0018] It is further defined that the long rectangular opening is disposed between the metal strip and the horizontal waveguide channel.

[0019] It is further defined that the first metal layer is formed by stamping a copper plate, or is formed by plastic followed by surface metallization, or is produced by CNC process, the second metal layer is produced by CNC process, or is formed by plastic followed by surface metallization, and the first metal layer and the second metal layer can be fixedly connected by screws, riveting or welding.

[0020] The beneficial effects of the present invention are as follows: the present invention provides a low sidelobe gap waveguide slot antenna based on artificial surface plasmon, which can effectively reduce manufacturing precision, reduce processing and manufacturing degree, save processing costs, and the waveguide antenna has low pitch sidelobe, strong anti-interference ability, and wide working bandwidth, which is very suitable for high-frequency band applications, mainly used in the millimeter wave region (30GHz-300GHz), but the present invention also has advantages at frequencies higher than 300GHz or lower than 30GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0022] Figure 1 This is a schematic diagram of the overall structure of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to an embodiment of the present invention;

[0023] Figure 2 1 is a front view and a rear view of a first metal layer of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to an embodiment of the present invention;

[0024] Figure 3 It is a front view and a rear view of the second metal layer of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to an embodiment of the present invention;

[0025] Figure 4(a) is a first waveguide port diagram of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to an embodiment of the present invention; Figure 4 (b) is Figure 4 (a) Schematic diagram of the structure of a circle of metal isolation belt loaded around the first waveguide port;

[0026] Figure 5 (a) is a front view of a vertical waveguide according to an embodiment of the present invention; Figure 5 (b) is a rear view of a vertical waveguide according to an embodiment of the present invention;

[0027] Figure 6 It is a front view of a second metal layer of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to an embodiment of the present invention;

[0028] Figure 7 It is a schematic diagram of a first variant of a transmission line in a low sidelobe gap waveguide slot antenna based on artificial surface plasmon in an embodiment of the present invention;

[0029] Figure 8 is a schematic diagram of a second variant of a transmission line in a low sidelobe gap waveguide slot antenna based on artificial surface plasmon in an embodiment of the present invention;

[0030] Fig. 9 is a schematic diagram of a third variant of a transmission line in a low sidelobe gap waveguide slot antenna based on artificial surface plasmon in an embodiment of the present invention;

[0031] Fig.10 This is a front schematic diagram of an eight-transmitter and eight-receiver low sidelobe gap waveguide slot array antenna based on artificial surface plasmon;

[0032] Fig.11 This is the front schematic diagram of a four-transmitter and four-receiver low sidelobe gap waveguide slot array antenna based on artificial surface plasmon;

[0033] Fig.12 It is a schematic diagram of the reflection coefficient of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon in an embodiment;

[0034] Fig.13 The invention is a normalized radiation pattern of a low sidelobe gap waveguide slot antenna based on artificial surface plasmon in an embodiment;

[0035] Fig.14 The invention provides a maximum frequency sweep gain within a working frequency band of a low sidelobe gap waveguide slot antenna based on artificial surface plasmons in an embodiment;

[0036] The main component symbols are described as follows:

[0037] A first metal layer 1 and a second metal layer 2;

[0038] Radiating opening 3, first short rectangular opening 301, second short rectangular opening 302, third short rectangular opening 303, fourth short rectangular opening 304, fifth short rectangular opening 305;

[0039] Long rectangular opening 4, horizontal waveguide channel 5, vertical waveguide channel 6, first waveguide opening 7, matching branch 8, metal strip 9 protrusion 10, groove 11, metal isolation belt 12, metal column 13, axis AA'. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0041] Embodiment 1

[0042] In this embodiment 1, Figure 1 As shown, a low sidelobe gap waveguide slot antenna based on artificial surface plasmon of the present invention includes a first metal layer 1 and a second metal layer 2.

[0043] like Figure 2 As shown, Figure 2 The left side is a front view of the first metal layer 1, Figure 2 The right side is a rear view of the first metal layer 1, which is provided with a radiation opening 3 and a plurality of long rectangular openings 4 for suppressing surface waves; the radiation opening 3 forms a port for radiating / receiving signals of the antenna through the short rectangular openings.

[0044] like Figure 3 As shown, Figure 3 The left side is a front view of the second metal layer 2, Figure 3 The right side is a rear view of the second metal layer 2. A horizontal waveguide channel 5 with its end vertically projected opposite to the radiation opening 3 is provided on the surface of the second metal layer 2 facing the first metal layer 1. A first waveguide port 7 is provided on the other side of the second metal layer 2 opposite to the first metal layer 1, wherein the first waveguide port 7 is connected to the starting end of the horizontal waveguide channel 5 through a vertical waveguide channel 6 penetrating the second metal layer 2. The horizontal waveguide channel 5 provided in the first metal layer 1 and the second metal layer 2 constitute a rectangular waveguide transmission line.

[0045] Combination Figure 2 and Figure 3 In the first metal layer 1, there are a first short rectangular opening 301, a second short rectangular opening 302, a third short rectangular opening 303, a fourth short rectangular opening 304, and a fifth short rectangular opening 305. These five short rectangular openings form ports for radiating / receiving signals of the antenna. The other five short rectangular openings are cross-symmetrically distributed along the axis AA' of the signal transmission direction of the horizontal waveguide channel 5, and their vertical projections are located in the horizontal waveguide channel.

[0046] In order to reduce the sidelobe level in the elevation direction of the antenna pattern, the positions and sizes of the five short rectangular openings are designed to be different. Specifically, the length and width of the first short rectangular opening 301 are exactly the same as those of the fifth short rectangular opening 305, and the first short rectangular opening 301 and the fifth rectangular opening 305 are both located on the same side of the axis AA' in the signal transmission direction of the horizontal waveguide channel 5, and are at the same distance from the axis AA'; the length and width of the second short rectangular opening 302 and the fourth short rectangular opening 304 are exactly the same, and the second short rectangular opening 302 and the fourth short rectangular opening 304 are both located on the signal transmission direction of the horizontal waveguide channel 5. In addition, the second short rectangular opening 302 and the fourth short rectangular opening 304 are not consistent in size with the first short rectangular opening 301 and the fifth short rectangular opening 305, and are respectively located on different sides of the axis AA' and are unequally distant from the axis; the length and width of the third short rectangular opening 303 are also completely inconsistent with those of the other four short rectangular openings, and are located on the same side of the axis AA' of the signal transmission direction of the horizontal waveguide channel 5 as the first short rectangular opening 301 and the fifth short rectangular opening 305, but are unequally distant from the axis AA'.

[0047] In addition to the five in the embodiment, the number of radiation openings 3 can be one, two, three, four, six...etc., and the odd-numbered short rectangular openings in the radiation openings 3 are located on the same side of the axis AA', the even-numbered short rectangular openings are located on another layer of the axis AA', and the odd-numbered and even-numbered short rectangular openings are staggered along the axis AA' and located on both sides of the axis AA'. In addition, if the requirements for the side lobe levels in the elevation direction of the antenna radiation pattern are not high, the sizes of all the short rectangular openings can also be completely consistent, and the distances from the axis are also the same.

[0048] In the first metal layer 1, long rectangular openings 4 are further provided on both sides of the radiation opening 3 along the axis AA' direction, and the long rectangular openings 4 are symmetrically distributed about the axis AA', and the distances from the axis AA' are equal or unequal, and the long rectangular openings 4 located on both sides of the axis AA' can be equal or unequal in length, and the long rectangular openings 4 located on both sides of the axis AA' can be one, two...etc., and the vertical projection of the long rectangular opening 4 is located between the side wall of the horizontal waveguide channel 5 and the metal strip 9.

[0049] The second metal layer 2 is provided with a horizontal waveguide channel 5 on one side facing the first metal layer 1 , the end of the horizontal waveguide channel 5 is opposite to the radiation opening 3 of the first metal layer 1 , and the starting end of the horizontal waveguide channel 5 is connected to the first waveguide opening 7 through a vertical waveguide channel 6 penetrating the second metal layer 2 .

[0050] The horizontal waveguide channel 5 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, partially electrically connected, or have a gap. The horizontal waveguide channel 5 can be straight or curved.

[0051] In order to reduce assembly tolerance and cost, a periodic or non-periodic artificial surface plasmon structure is arranged on the outer side of the side wall of the horizontal waveguide channel 5 perpendicular to the horizontal plane of the second metal layer 2. This structure can confine the transmitted electromagnetic energy in the horizontal waveguide channel 5 when there is a gap between the first metal layer 1 and the second metal layer 2, and make the electromagnetic signal transmitted in the desired direction.

[0052] The artificial surface plasmon structure is realized by etching periodic or non-periodic grooves 11 on the outer side of the side wall of the horizontal waveguide channel 5 , and the protrusions 10 between adjacent grooves are electrically connected to the outer side of the side wall of the horizontal waveguide channel 5 .

[0053] The height of the protrusion 20 perpendicular to the horizontal plane of the second metal layer 2 may be equal to or different from the sidewall of the horizontal waveguide channel 5 ; the width and depth of adjacent grooves 11 may be equal or different.

[0054] A metal strip 9 is further provided at the end of the horizontal waveguide channel 5 and on both sides of the radiation opening 3, wherein the metal strips 9 are symmetrically distributed on both sides of the radiation opening 3 about the axis AA'; the metal strip 9 may be rectangular, or may be provided with a periodic or non-periodic corrugated groove on one side close to the side wall of the horizontal waveguide channel 5, and furthermore, the metal strip 9 maintains a distance of at least 0.3 mm from the outer side of the side wall of the horizontal waveguide channel 5; the vertical projection of the long rectangular opening 4 is located between the metal strip 9 and the side wall of the horizontal waveguide channel 5, and as described above, the metal strip 9 and the long rectangular opening 4 may suppress surface waves, thereby improving the radiation performance of the antenna.

[0055] A first waveguide opening 7 is also provided in the second metal layer 2, which is located on the side of the second metal layer 4 facing opposite to the first metal layer 1, and a periodic or non-periodic artificial surface plasmon structure is provided around the first waveguide opening 7. The protrusion 10 of the artificial surface plasmon structure is electrically connected to the side wall of the first waveguide opening 7, and its height can be the same or different from the side wall of the first waveguide opening 7, and the shapes of adjacent grooves 11 can be the same or different.

[0056] Whether it is the outer side of the side wall of the horizontal waveguide channel 5 or the outer side of the first waveguide port 7, the shape of the protrusions 10 and the grooves 11 contained in the artificial surface plasmon structure provided thereon can be rectangular, elliptical, semicircular, triangular or the like.

[0057] In order to improve the antenna performance, a matching branch 8 is further provided at the junction of the starting end in the horizontal waveguide channel 5 and the vertical waveguide channel 6, wherein: the matching branch 8 is located at the bottom side of the horizontal waveguide channel 5 and is electrically connected to the bottom side; the starting end of the matching branch 8 extends into the vertical waveguide channel 6 or to the edge of the vertical waveguide channel 6, and the end is horn-shaped;

[0058] The low sidelobe gap waveguide slot antenna based on artificial surface plasmon of the present invention can also be formed into an array form, such as four transmitters and four receivers (such as Fig.11 As shown), eight sends and eight receives (as shown Fig.10 Arrays such as those shown in the figure also adopt a two-layer structure, namely a first metal layer 1 and a second metal layer 2.

[0059] Figure 4 A detailed diagram of the first waveguide port 7 in the first embodiment is given, wherein Figure 4 (a) The outer side of the first waveguide port 7 is an artificial surface plasmon structure, and Figure 4 (b) Figure 4 On the basis of (a), a circle of metal isolation belt 12 is arranged at a certain distance on the outside of the artificial surface plasmon structure. The number of circles of the metal isolation belt 12 can be two circles, three circles, etc. in addition to the one circle shown in the figure. This can better prevent the energy leakage caused by the gap when the PCB and the waveguide antenna are connected. In addition, the vertical waveguide channel 6 in the first embodiment is a double-ridge waveguide structure.

[0060] Embodiment 2

[0061] like Figure 6 As shown,

[0062] Compared with the first embodiment, the second embodiment also has a two-layer structure, namely, a first metal layer 1 and a second metal layer 2, wherein the first metal layer 1 in the second embodiment is the same as the first metal layer 1 in the first embodiment, and the second metal layer 2 in the second embodiment is different from the second metal layer 2 in the first embodiment in two places: first, the vertical waveguide channel 6 in the first embodiment is a double-ridge structure, while in the second embodiment, the structure of the vertical waveguide channel 6 is changed from a double-ridge structure to a rectangular structure; second, the starting end of the matching branch node 8 in the first embodiment coincides with one of the double ridges of the vertical waveguide channel 6 in the vertical projection, while the starting end of the matching branch node 8 in the second embodiment extends to the inner side of the rectangular vertical waveguide channel. Except for these two differences, the other designs are consistent with those of the first embodiment.

[0063] In the second embodiment, the outer side of the first waveguide opening 7 is not Figure 5 (b) In addition to setting up the artificial surface plasmon structure, it can also be set up in Figure 5 (b) Based on the image Figure 4(b) A metal isolation belt 12 is disposed at a certain distance outside the artificial surface plasmon structure. The number of turns of the metal isolation belt 12 can be one turn, two turns, etc.

[0064] The assembly and working principle of the first metal layer 1 and the second metal layer 2 of the second embodiment are consistent with those of the first embodiment.

[0065] Embodiment 3

[0066] like Figure 6 As shown, the third embodiment and the first two embodiments all adopt a two-layer structure design, and the first metal layer 1 is consistent with the first two embodiments. The only difference is that the metal strip 9 facing the first metal layer 1 of the second metal layer 2 of the third embodiment is different from that of the other embodiments. Specifically, in the first embodiment, the metal strip 9 is provided with periodic or non-periodic grooves 11 on one side close to the side of the horizontal waveguide channel 5, while in the third embodiment, the metal strip 9 is a conventional rectangular metal strip.

[0067] Figure 7 is the first variant of all embodiments of the present invention, wherein Figure 7 (a) is to load periodic or non-periodic metal pillars 13 on the side wall of the horizontal waveguide channel 5. In this case, the first metal layer and the second metal layer 2 are designed without gaps. Figure 7 (b) A periodic or non-periodic metal column 13 is loaded on the protrusion 10 electrically connected to the side wall of the horizontal waveguide channel 5. The first metal layer 1 and the second metal layer 2 of this structure are also designed without gaps;

[0068] Figure 8 is the second variant of all embodiments of the present invention, wherein Figure 8 (a) is a side view of the second variant, Figure 8 (b) is an oblique view of the second variant. In this structure, the first metal layer 1 and the second metal layer 2 can be designed with or without a gap. When there is a gap between the first metal layer 1 and the second metal layer 2, the electromagnetic energy will be bound by the artificial surface plasmon structure and the metal isolation belt on both sides of the horizontal waveguide channel 5, thereby ensuring that the electromagnetic energy is transmitted along the desired direction.

[0069] Fig. 9 is the third variation of all embodiments of the present invention, wherein Fig. 9 (a) is a side view of the third variant. Fig. 9(b) is an oblique view of the third variant, in which the artificial surface plasmon structure is located on the inner side of the side wall of the horizontal waveguide channel 5 and is electrically connected to the side wall. A metal column 13 is electrically connected above the protrusion 10 of the artificial surface plasmon structure. The first metal layer 1 and the second metal layer 2 of this structure can be designed to be gapless or have a gap. When there is a gap between the first metal layer 1 and the second metal layer 2, the electromagnetic energy will be bound by the artificial surface plasmon structure and the metal isolation belt on both sides of the horizontal waveguide channel, thereby ensuring that the electromagnetic energy is transmitted along the desired direction.

[0070] The operating frequency band of the vehicle-mounted millimeter-wave radar is generally 76--81GHz. Fig.12 The simulated reflection coefficient diagram of the low sidelobe gap waveguide slot antenna based on artificial surface plasmon in Example 1 is given. Fig.12 It is known that the reflection coefficient bandwidth based on -10dB is from 74.5 to 82GHz, achieving a working bandwidth of 7.5GHz, and the working bandwidth is much larger than the working bandwidth of millimeter wave radar 76-81GHz, which leaves bandwidth redundancy for the frequency deviation caused by the tolerance of actual processing and manufacturing.

[0071] Fig.13 The normalized radiation pattern of the antenna of Example 1 is given. It can be seen that the sidelobe level of the antenna radiation pattern in the elevation direction is lower than -20dB, which provides a strong anti-interference capability for 4D millimeter-wave radar to detect targets in the elevation direction. Fig.14 The maximum gain of the frequency sweep within the operating frequency band of 76-81 GHz for the vehicle-borne millimeter-wave radar is given, which means that the gain of the low sidelobe gap waveguide slot antenna based on artificial surface plasmon of the present invention is excellent in the entire frequency band.

[0072] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A low sidelobe gap waveguide slot antenna based on artificial surface plasmon, characterized in that: It comprises a first metal layer (1) and a second metal layer (2); The first metal layer (1) is provided with a radiation opening (3) and a plurality of long rectangular openings (4) for suppressing surface waves; the second metal layer (2) is provided with a horizontal waveguide channel (5) on the surface facing the first metal layer (1); the first metal layer (1) and the horizontal waveguide channel (5) provided in the second metal layer (2) form a rectangular waveguide transmission line; the end of the horizontal waveguide channel (5) is vertically projected to be directly opposite to the radiation opening (3) of the first metal layer (1); the second metal layer (2) is provided with a vertical waveguide channel (6) at the beginning of the horizontal waveguide channel (5); the back of the second metal layer (2) is provided with a first waveguide port (7); the first waveguide port (7) is connected to the beginning of the horizontal waveguide channel (5) through the vertical waveguide channel (6).

2. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 1, characterized in that: The radiation opening (3) comprises a first short rectangular opening (301), a second short rectangular opening (302), a third short rectangular opening (303), a fourth short rectangular opening (304) and a fifth short rectangular opening (305); 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 cross-symmetrically distributed along an axis (AA') in the signal transmission direction of the horizontal waveguide channel (5), and the vertical projections of the five short rectangular openings are located within the horizontal waveguide channel (5); The length and width of the first short rectangular opening (301) and the fifth short rectangular opening (305) are completely consistent, and the first short rectangular opening (301) and the fifth short rectangular opening (305) are both located on the same side of the axis (AA') of the signal transmission direction of the horizontal waveguide channel (5), and are at the same distance from the axis (AA'); The length and width of the second short rectangular opening (302) and the fourth short rectangular opening (304) are completely consistent, and the second short rectangular opening (302) and the fourth short rectangular opening (304) are both located on the same side of the axis (AA') of the signal transmission direction of the horizontal waveguide channel (5), and are at the same distance from the axis (AA'); the second short rectangular opening (302) and the fourth short rectangular opening (304) are different in size from the first short rectangular opening (301) and the fifth short rectangular opening (305), and are respectively located on different sides of the axis (AA') and are at unequal distances from the axis (AA'); The length and width of the third short rectangular opening (303) are different from those of the first short rectangular opening (301), the second short rectangular opening (302), the fourth short rectangular opening (304) and the fifth short rectangular opening (305), and the third short rectangular opening (303) is located on the same side of the axis (AA') of the signal transmission direction of the horizontal waveguide channel (5) as the first short rectangular opening (301) and the fifth short rectangular opening (305), but at different distances from the axis (AA').

3. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 2, characterized in that: The number of the radiation openings (3) is one or more, and the odd-numbered short rectangular openings in the radiation openings (3) are located on the same side of the axis (AA'), and the even-numbered short rectangular openings are located on the other side of the axis (AA'), and the odd-numbered short rectangular openings and the even-numbered short rectangular openings are cross-symmetrically distributed along the axis (AA'); the sizes 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) can also be completely consistent, and the distances from the axis are also the same.

4. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 3, characterized in that: The long rectangular opening (4) is symmetrically arranged on both sides of the radiation opening (3) along the axis (AA'), the distances between the long rectangular openings (4) on both sides and the axis (AA') are equal or unequal, the long rectangular openings (4) on both sides can be arranged in equal lengths or unequal lengths, the number of the long rectangular openings (4) arranged on both sides of the axis (AA') is one or more, and the vertical projection of the long rectangular opening (4) cannot be located in the horizontal waveguide channel (5).

5. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 4, characterized in that: The horizontal waveguide channel (5) is arranged in a curved structure, and may also be arranged in a straight structure. The horizontal waveguide channel (5) 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) are completely electrically connected, or partially electrically connected, or there is a gap.

6. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 5, characterized in that: The first waveguide port (7) and the horizontal waveguide channel (5) are provided with an artificial surface plasmon structure on the outer side wall perpendicular to the second metal layer (2), the artificial surface plasmon structure comprising a plurality of grooves (11) arranged on the outer side wall of the horizontal waveguide channel (5), a protrusion (10) being provided between two adjacent grooves (11); the protrusion (10) and the groove (11) are in the shape of a rectangle, an ellipse, a semicircle or a triangle.

7. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 6, characterized in that: The horizontal waveguide channel (5) is provided with a matching branch node (8) at the junction with the vertical waveguide channel (6); the matching branch node (8) is arranged at the bottom side of the horizontal waveguide channel (5) and is electrically connected to the bottom side of the horizontal waveguide channel (5); the starting end of the matching branch node (8) extends into the vertical waveguide channel (6) or to the edge of the vertical waveguide channel (6), and the end thereof is arranged in a trumpet-shaped structure.

8. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 7, characterized in that: The second metal layer (2) is symmetrically provided with metal strips (9) on both sides of the radiation opening (3); the metal strips (9) are arranged in a rectangular structure; the metal strips (9) may also be provided with corrugated grooves on the side wall close to the horizontal waveguide channel (5); and a distance of at least 0.3 mm is maintained between the metal strips (9) and the outer side wall of the horizontal waveguide channel (5).

9. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 8, characterized in that: The long rectangular opening (4) is arranged between the metal strip (9) and the horizontal waveguide channel (5).

10. The low sidelobe gap waveguide slot antenna based on artificial surface plasmon according to claim 9, characterized in that: The first metal layer (1) is formed by stamping a copper plate, or by metallizing the surface after plastic molding, or by CNC process production; the second metal layer (2) is produced by CNC process production, or by metallizing the surface after plastic molding; the first metal layer (1) and the second metal layer (2) can be fixedly connected by screws, riveting or welding.

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