Double-frequency broadband large-angular-domain high-gain antenna based on cavity structure

Abstract

The invention discloses a double-frequency broadband large-angular-domain high-gain antenna based on a cavity structure. The antenna mainly solves the problems that an existing antenna cannot meet the requirements of wide frequency band, high gain of a large angular domain near an end-fire direction and conformal installation at the same time. The antenna comprises a radome (1), a metal cavity (2), three sealing rings (3, 7 and 8), two radiators (4 and 5) and a connector (6), the radome comprises a radome front end, a radome flange and an air conditioning cavity from top to bottom, and the influence of the size non-uniformity of the radome on the antenna performance can be eliminated by changing the shape and size of the air conditioning cavity; the two radiators are located in the metal cavity and jointly adjust the angular domain range of the antenna; the first sealing ring (3) is positioned between the antenna housing and the metal cavity; second and third sealing rings (7, 8) are located between the metal cavity and the connector. The antenna has the advantages of being wide in frequency band, high in large angular domain gain near the end-fire direction and easy to conform, is high in water-pressure-resistant sealing performance, and is suitable for ground radar equipment and submarine radar equipment.

Description

Technical Field

[0001] The invention belongs to the field of radar equipment antennas, and in particular relates to a dual-frequency, wide-band, large-angle, high-gain antenna that can be used on a mobile platform. Background Art

[0002] With the continuous development of modern radar equipment, the requirements for antennas in radar equipment are getting higher and higher. Antennas must not only meet the requirements of wide bandwidth and conformal installation, but also meet the requirements of high gain in specific angular domains under different installation environments. K-band and Ka-band antennas have the advantages of small size and light weight, and have broad application prospects on mobile platforms.

[0003] The main forms of antennas are waveguide slot antennas, parabolic antennas, microstrip antennas, and horn antennas. Among them, waveguide slot antennas and parabolic antennas have relatively high profiles, relatively large volumes and weights, and are not easy to conform to the equipment; microstrip antennas have low profiles, small volumes, light weights, and are easy to conform to, but the microstrip antenna feeder loss is large, and the gain in the large angular area near the end-fire direction of the antenna is low, the bandwidth is narrow, and there will be a spatial blind area, which cannot meet the communication needs of radar equipment; horn antennas have simple structure and feeding, wide bandwidth, and high efficiency, but horn antennas also have low gain in the large angular area near the end-fire direction, and there will be a spatial blind area, which cannot meet the communication needs of radar equipment.

[0004] The utility model patent with the authorization announcement number CN 218997080 U discloses a vacuum-designed high-power antenna unit, which forms a simple and easy-to-install sealed structure by adding an antenna cover, a sealing ring, and a sealing groove on the basis of a horn antenna. Although the antenna unit has the characteristics of wide bandwidth and high gain, its maximum gain points to the normal direction, and its gain is low in a large angular range near the end-fire direction, so it will produce a spatial blind spot when used, which cannot meet communication needs. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to propose a dual-band, broadband, large-angle, high-gain antenna based on a cavity structure, so as to expand the wide-angle coverage near the end-fire direction of the antenna while meeting the bandwidth and conformal installation requirements, avoid spatial blind spots in communication, and meet the communication needs of equipment.

[0006] To achieve the above object, the present invention provides a dual-band, wide-angle, high-gain antenna based on a cavity structure, comprising a radome, a metal cavity, three sealing rings, two radiators and a connector, and is characterized in that:

[0007] The radome includes, from top to bottom, a radome front end, a radome flange and an air conditioning cavity, and the shape and size of the air conditioning cavity are changed to eliminate the influence of the radome size non-uniformity on the antenna performance;

[0008] The metal cavity comprises, from top to bottom, a sealing groove, an upper cavity flange, an air cavity and a lower cavity flange;

[0009] The two radiators are both arranged in the air cavity, and the three together adjust the angular range of the antenna.

[0010] Preferably, the two radiators are both designed by deformation based on the pyramid horn, and the deflection angles thereof are 0.3 to 0.7 times of the maximum radiation angle in the angular domain.

[0011] Preferably, the front end of the radome is conformally designed according to the shape of the installation platform and the size of the opening, so as to meet the conformal installation requirements of any platform while ensuring the antenna performance.

[0012] Preferably, the antenna cover mounting flange has the same outer dimensions as the flange on the metal cavity, and is fastened together so that the upper surface of the metal cavity fits tightly with the lower surface of the antenna cover.

[0013] Preferably, the air cavity contains multiple adjustable parameters, including: inner cavity width B5, inner cavity length B6, inner cavity height B8, and distance B4 between two radiators; by adjusting these adjustable parameters and the deflection angles of the two radiators, the angular range of the antenna can meet the design requirements.

[0014] The antenna radiator of the present invention is a deformation design with two independent functions on the basis of a pyramid horn, and the gain within a specific angular range of the antenna is adjusted by optimizing the radiator and the metal cavity size, so that the antenna can not only have the characteristics of a wide working frequency band, but also meet the communication requirements of radar equipment in different angular regions, so that the radar equipment can simultaneously transmit and receive signals; at the same time, since the top layer of the antenna of the present invention adopts a wave-transparent antenna cover, it is easy to conform and convenient for conformal installation on different platforms; in addition, since sealing rings are used between the antenna cover and the metal cavity, and between the metal cavity and the connector, the antenna has a strong water pressure sealing performance, and is not only suitable for ground radar equipment, but also for submarine radar equipment, and has a wider application platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0016] Figure 2 It is a structural explosion diagram of the present invention;

[0017] Figure 3 It is a schematic structural diagram of the antenna cover 1 in the present invention;

[0018] Figure 4 It is a schematic diagram of the structure of the metal cavity 2 in the present invention;

[0019] Figure 5 is a schematic structural diagram of the first radiator 4 in the present invention;

[0020] Figure 6 is a schematic structural diagram of the second radiator 5 in the present invention;

[0021] Figure 7 It is a schematic diagram of the structure of the connector 6 in the present invention;

[0022] Figure 8 This is a simulation result diagram of the K-band standing wave coefficient of an embodiment of the present invention;

[0023] Fig. 9 This is a simulation result diagram of the K-band directional pattern of an embodiment of the present invention;

[0024] Fig.10 This is a simulation result diagram of the Ka-band standing wave coefficient of an embodiment of the present invention;

[0025] Fig.11 This is a diagram of the simulation results of the Ka-band directional pattern of an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The embodiments and effects of the present invention are described in detail below with reference to the accompanying drawings.

[0027] Reference Figure 1 and Figure 2 The antenna of this embodiment includes an antenna cover 1, a metal cavity 2, a first sealing ring 3, a first radiator 4, a second radiator 5, a connector 6, a second sealing ring 7, and a third sealing ring 8, and can be divided into three layers from top to bottom, wherein the antenna cover 1 is located at the top layer, the metal cavity 2 is located in the middle layer, the connector 6 is located at the bottom layer, the first sealing ring 3 is located between the antenna cover 1 and the metal cavity 2, the first radiator 4 and the second radiator 5 are located inside the metal cavity 2, and the second sealing ring 7 and the third sealing ring 8 are located between the metal cavity 2 and the connector 6.

[0028] The above-mentioned antenna cover 1 is used for conformal connection between the antenna and the installation platform; the metal cavity 2 and the two radiators are used together to form a specific radiation angle domain; the first radiator 4 is used to transmit the energy signal of the first working frequency band of the antenna, and the second radiator 5 is used to transmit the energy signal of the second working frequency band of the antenna. The two working frequency bands of the antenna are selected according to the requirements of the radar system; the connector 6 is used for the transmission and conversion of dual-band signals; the three sealing rings are used together to isolate the inner and outer spaces of the metal cavity 2 and seal and protect the two radiators.

[0029] When the antenna is working, the two frequency bands can transmit and receive at the same time, or one frequency band can transmit and the other frequency band can receive; its working principle is as follows:

[0030] When the antenna is in the transmitting state, the electrical signal transmitted by the rear-end radar equipment is converted into an electromagnetic wave through the connector 6, and then the electromagnetic wave is radiated to the surrounding through the first radiator 4 and the second radiator 5. When the electromagnetic wave reaches the wall structure of the metal cavity 2, it will be reflected, changing the propagation path of the electromagnetic wave; these reflected electromagnetic waves and the directly radiated electromagnetic waves are vector-superimposed on the mouth surface of the metal cavity 2 to form a phase plane pointing to the required angular domain, and the electromagnetic waves that have completed vector superposition are radiated outward through the antenna cover 1.

[0031] When the antenna is in the receiving state, external electromagnetic waves enter the metal cavity 2 through the antenna cover 1. Part of the electromagnetic waves reaches the wall structure of the metal cavity 2, is reflected, and then reaches the mouth of the first radiator 4 and the second radiator 5. The other part of the electromagnetic waves directly reaches the mouth of the first radiator 4 and the second radiator 5. After the vector superposition of the two, they enter the first radiator 4 and the second radiator 5, and then the electromagnetic waves are converted into electrical signals through the connector 6 and input into the back-end radar equipment.

[0032] In this embodiment, the first operating frequency band is set to but not limited to 23 GHz to 26.5 GHz; the second operating frequency band is set to but not limited to 26.8 GHz to 35 GHz, and the angular range between the first frequency band and the second frequency band is set to but not limited to -75° to 0°.

[0033] refer to Figure 3 , where 3(a) is a front view, 3(b) is a top view, and 3(c) is a side view. The radome 1 includes a radome front end 11, a radome flange 12, and an air conditioning chamber 13 from top to bottom. The radome thickness h is the initial value calculated according to the material optimal wave transmission formula under the premise of satisfying the structural strength. The calculation formula is:

[0034]

[0035] Where λ0 represents the wavelength of the antenna's operating center frequency, ε r represents the dielectric constant of the material, θ represents the incident angle of the electromagnetic wave, i.e. the deflection angle of the radiator, and m represents any positive integer;

[0036] In this example, the antenna has two working frequency bands, and the center frequency of the high frequency band is used as the initial value for calculation. By changing the shape and size of the air conditioning cavity 13, both working frequency bands can meet the wave transmission requirements.

[0037] The shape and size of the front end 11 of the radome and the radome flange 12 are determined according to the surface equation corresponding to the installation platform and the antenna installation position, that is, the outer length A1 and the outer width A2 of the installation flange 12, the length A3 and the width A4 of the front end of the radome, the distance A5 from the edge of the front end of the radome to the highest point of the radome flange, and the distance A6 from the edge of the front end of the radome to the lowest point of the radome flange are determined; the radome determined according to the surface equation provided by the installation platform meets the conformal requirements of the platform; the size of the air conditioning cavity 13 and the thickness h of the radome are adjusted by modeling and simulation, so as to eliminate the influence of the uneven overall size of the radome due to the different curvatures between different installation platforms on the antenna performance, and determine the final size of the radome.

[0038] In some embodiments, the curvature of the mounting platform is larger, the corresponding radome protrusion is more obvious, its shape is closer to a part of a sphere, the overall unevenness of the radome is stronger, and the corresponding air conditioning cavity surface also needs to be adjusted to a curved surface; in other embodiments, the curvature of the mounting platform is smaller, the corresponding radome surface is flatter, its shape is closer to a rectangle, and the corresponding air conditioning cavity surface can also be adjusted to a flat surface.

[0039] In this embodiment, the radome material is set to, but not limited to, cyanate quartz fiber preformed with a dielectric constant of 3.1 and a loss tangent of 0.007. Material; the shape of the front end of the radome and the upper surface of the radome flange is set to but not limited to satisfy the surface equation x 2 +y 2 +z 2 =R 2 , R represents the radius of the spherical surface.

[0040] refer to Figure 4 4(a) is a top view and 4(b) is a cross-sectional view. The metal cavity 2 includes a sealing groove 21, a cavity upper flange 22, an air cavity 23 and a cavity lower flange 24 from top to bottom.

[0041] A first sealing ring 3 is placed in the sealing groove 21 to seal the upper end of the metal cavity and protect the internal environment of the cavity;

[0042] The outer profile length B1 and outer profile width B2 of the cavity upper flange 22 are respectively the same as the outer profile length A1 and outer profile width A2 of the radome mounting flange 12, and the two are tightly connected so that the upper surface of the metal cavity and the lower surface of the radome are closely matched;

[0043] Two radiators are placed inside the air cavity 23. Through modeling and simulation, the dimension B3 of the installation position of the first radiator 4 from the edge of the metal cavity, the distance B4 between the second radiator 5 and the first radiator 4, and the inner cavity length B5, inner cavity width B6, and inner cavity depth B8 of the air cavity are adjusted to optimize the radiation performance of the antenna in a specific angular region.

[0044] The cavity lower flange 24 is located on the central axis of the cavity and is used to install the connector 6;

[0045] refer to Figure 5 The first radiator 4 is fixed on the lower surface of the inner wall of the metal cavity, and includes an excitation waveguide 41 and a radiation waveguide 42; the size of the excitation waveguide 41 is selected according to the standard waveguide size table according to the requirements of the selected first working frequency band, and the initial value of the deflection angle θ1 of the excitation waveguide 41 is calculated according to the required angular domain range; then, the directional diagram of a specific angular domain is simulated by modeling, and the deflection angle θ1, bending radius r1 of the excitation waveguide and the height C1, aperture length C2, and aperture width C3 of the radiation waveguide are optimized to make the angular domain range and radiation performance of the antenna meet the design requirements, and the optimized parameter value is the final value.

[0046] In this example, the excitation waveguide 41 uses but is not limited to the standard BJ260 rectangular waveguide, that is, C4 is 8.636 mm and C5 is 4.318 mm; according to the maximum angular range of the end-fire direction being -75°, the initial value of the deflection angle θ1 of the excitation waveguide 41 is set to but is not limited to 50°.

[0047] refer to Figure 6 In this embodiment, the second radiator 5 is composed of an excitation waveguide 51 and a radiation waveguide 52, which is fixed on the lower surface of the inner wall of the metal cavity and is on the same horizontal plane as the first radiator 4; the principle for selecting the size of the excitation waveguide 51 and the initial value of the deflection angle θ2 is the same as the principle for selecting the size of the excitation waveguide 41 and the initial value of the deflection angle θ1; the final values ​​of the deflection angle θ2 and the bending radius r2 of the excitation waveguide 51 and the height D1, the aperture length D2, and the aperture length D3 of the radiation waveguide 52 are determined by modeling and simulation.

[0048] In this example, according to the working frequency requirements, the excitation waveguide 51 is selected but not limited to the standard BJ320 rectangular waveguide, that is, D4 is 7.112 mm, D5 is 3.556 mm; the initial value of the deflection angle θ2 of the excitation waveguide 51 is set to be, but not limited to, 50° according to the angular domain range;

[0049] refer to Figure 7 The connector 6 is used to coaxially integrate two waveguides and is designed to be water pressure-resistant and sealed. From top to bottom, it includes a mounting flange 61, two connector sealing grooves 62 and 63, and two waveguide coaxial converters 64 and 65.

[0050] The outer dimensions of the mounting flange 61 are consistent with those of the cavity lower flange 24, and are tightly connected so that the upper surface of the connector is tightly matched with the lower surface of the cavity lower flange;

[0051] The connector sealing groove 63 is used to install the second sealing ring 7, and the connector sealing groove 62 is used to install the third sealing ring 8; the two sealing rings are used together to seal the lower end of the metal cavity and protect the internal environment of the cavity.

[0052] The inner wall size of the cavity of the first waveguide coaxial converter 64 is consistent with the inner wall size of the radiator excitation waveguide 41 , and the inner wall size of the cavity of the second waveguide coaxial converter 65 is consistent with the inner wall size of the radiator excitation waveguide 51 .

[0053] In this example, the inner wall size of the waveguide cavity 64 is set to, but not limited to, 8.636 mm×4.318 mm; the inner wall size of the waveguide cavity 65 is set to, but not limited to, 7.112 mm×3.556 mm.

[0054] The effect of the present invention can be further illustrated by the following simulation results.

[0055] 1. Simulation conditions

[0056] The HFSS electromagnetic simulation software is used to establish the electromagnetic simulation model of the embodiment of the present invention.

[0057] The electromagnetic simulation model of the embodiment of the present invention includes two working frequency bands: K band and Ka band. Its structural parameters are set as follows:

[0058] Radome: Its outer contour length A1 is 74.5mm, outer contour width A2 is 65.0mm, the length A3 of the front end of the radome is 58.5mm, the width A4 is 49mm, the distance A5 from the edge of the front end of the radome to the highest point of the radome flange is 1.51mm, the distance A6 from the edge of the front end of the radome to the lowest point of the radome flange is 1.85mm, and the thickness h of the radome is 6.0mm; the size of the air conditioning cavity is 20mm×10mm×0.35mm;

[0059] Metal cavity: the outer contour length B1 of the upper flange 22 of the cavity is 74.5 mm, the outer contour width B2 is 65 mm, the dimension B3 of the installation position of the first radiator 4 from the edge of the metal cavity is 36.35 mm, the distance B4 between the second radiator 5 and the first radiator 4 is 23.70 mm, the inner cavity length B5 of the air cavity 23 is 39 mm, the inner cavity width B6 is 51.5 mm, the inner cavity depth B8 is 18.9 mm, and the thickness B7 of the lower flange 24 of the cavity is 4.0 mm;

[0060] The first radiator 4: the deflection angle θ1 of the excitation waveguide 41 is 50°, the bending radius r1 is 4.23 mm, the height C1 of the radiation waveguide 42 is 12 mm, the aperture length C2 is 10.0 mm, the aperture width C3 is 9.0 mm, the length C4 of the excitation waveguide 41 is 8.636 mm, and the width C5 is 4.318 mm;

[0061] The second radiator 5: the deflection angle θ2 of the excitation waveguide 51 is 50°, the bending radius r2 is 18.4 mm, the height D1 of the radiation waveguide 52 is 9.0 mm, the mouth length D2 is 7.5 mm, the mouth length D3 is 5.0 mm, the length D4 of the excitation waveguide 51 is 7.112 mm, and the width D5 is 3.556 mm.

[0062] 2. Simulation content

[0063] Simulation 1: The K-band standing wave coefficient of the electromagnetic simulation model of the antenna in the above embodiment of the present invention is simulated, and the result is as follows: Figure 8 .from Figure 8 It can be seen that the standing wave coefficient of the antenna is 1.2943 at a frequency of 23 GHz, and the corresponding standing wave coefficient is 1.2645 at a frequency of 26.45 GHz. The maximum standing wave coefficient in the frequency band of 23 GHz to 26.5 GHz is 1.3196, and the corresponding frequency is 25.15 GHz. It can be concluded that the standing wave coefficient of the antenna in the K band is less than 1.35 in the range of 23 GHz to 26.5 GHz.

[0064] Simulation 2: The K-band directional pattern of the electromagnetic simulation model of the antenna of the above embodiment of the present invention is simulated, and the result is as follows: Fig. 9 .from Fig. 9 It can be seen that the corresponding gain of the antenna is 6.3709dB when the angle is -75°, and the corresponding gain is 8.7782dB when the angle is 0°. The minimum gain in the angular range of -75° to 0° is 3.9169dB, corresponding to an angle of -9°. It can be concluded that the gain of the antenna in the K band angular range of -75° to 0° is greater than 3.9dB.

[0065] Simulation 3: The Ka-band standing wave coefficient of the electromagnetic simulation model of the antenna of the above embodiment of the present invention is simulated, and the result is as follows: Fig.10 .from Fig.10 It can be seen that the standing wave coefficient of the antenna is 1.2968 at a frequency of 26.8 GHz, and the corresponding standing wave coefficient is 1.2598 at a frequency of 35 GHz. The maximum standing wave coefficient in the frequency band of 26.8 GHz to 35 GHz is 1.2968, and the corresponding frequency is 26.8 GHz. It can be concluded that the standing wave coefficient of the antenna in the Ka band is less than 1.35 in the range of 26.8 GHz to 35 GHz.

[0066] Simulation 4: The Ka-band radiation pattern of the electromagnetic simulation model of the antenna of the above embodiment of the present invention is simulated, and the result is as follows: Fig.11 .from Fig.11It can be seen that the corresponding gain of the antenna is 3.2011dB when the angle is -75°, and the corresponding gain is 4.2605dB when the angle is 0°. The minimum gain in the angular range of -75° to 0° is 2.8592dB, and the corresponding angle is -14°. It can be concluded that the gain of the antenna in the end-fire direction of the Ka band is greater than 2.8dB in the angular range of -75° to 0°.

[0067] The above simulation results show that the dual-band, wide-angle, high-gain antenna based on the cavity structure of the present invention has a standing wave coefficient less than 1.35, which is greater than 14% in the K band and greater than 26% in the Ka band; the gain in the angular range of -75° to 0° is greater than 2.8dB, indicating that the present invention has a wide-band, high-gain radiation performance in a large angular range near the end-fire direction.

[0068] The above description is only a specific example of the present invention and does not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and principles of the present invention, it is possible to make various modifications and changes in form and details without departing from the principles and structures of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A dual-band, wide-angle, high-gain antenna based on a cavity structure, comprising a radome (1), a metal cavity (2), three sealing rings (3, 7, 8), two radiators (4, 5), and a connector (6), characterized in that: The radome (1) comprises, from top to bottom, a radome front end (11), a radome flange (12) and an air conditioning chamber (13), and the shape and size of the air conditioning chamber (13) are changed to eliminate the influence of the radome size non-uniformity on the antenna performance; The metal cavity (2) comprises, from top to bottom, a sealing groove (21), a cavity upper flange (22), an air cavity (23) and a cavity lower flange (24); The two radiators (4, 5) are both arranged in the air cavity (23), and the three together adjust the angular range of the antenna.

2. The antenna according to claim 1, characterized in that The two radiators (4, 5) are both designed by deformation based on a pyramid horn, and the deflection angle θ1 of the first radiator (4) and the deflection angle θ2 of the second radiator (5) are both 0.3 to 0.7 times the maximum radiation angle in the angular domain.

3. The antenna according to claim 1, characterized in that The front end (11) of the radome is conformally designed according to the shape of the installation platform and the size of the opening, so as to meet the conformal installation requirements of any platform while ensuring the antenna performance.

4. The antenna according to claim 1, characterized in that: The antenna cover mounting flange (12) has the same outer dimensions as the upper flange (22) of the metal cavity and is tightly connected so that the upper surface of the metal cavity fits tightly with the lower surface of the antenna cover.

5. The antenna according to claim 1, characterized in that The total thickness h of the radome (1) is given an initial value based on the optimal wave transmission formula of the material used in the radome in two working frequency bands, under the premise of satisfying the structural strength, and then the final value is determined through simulation optimization in combination with the adjustment of the size and shape of the air conditioning chamber (13).

6. The antenna according to claim 1, characterized in that The air cavity (23) contains a plurality of adjustable parameters, including: an inner cavity width B5, an inner cavity length B6, an inner cavity height B8, a dimension B3 of the installation position of the first radiator (4) from the edge of the metal cavity, and a distance B4 between the second radiator (5) and the first radiator (4); by adjusting these adjustable parameters and the deflection angles θ1 and θ2 of the first radiator (4) and the second radiator (5), the angular range of the antenna meets the design requirements.

7. The antenna according to claim 1, characterized in that: Two radiators (4, 5) have the following structure: The first radiator (4) comprises, from bottom to top, an excitation waveguide (41) and a radiation waveguide (42), and the performance of the first working frequency band of the antenna is optimized by adjusting the bending radius r1 of the excitation waveguide (41) and the height C1, the aperture length C2, and the aperture width C3 of the radiation waveguide (42); The second radiator (5) comprises an excitation waveguide (51) and a radiation waveguide (52), and the performance of the second working frequency band of the antenna is optimized by adjusting the bending radius r2 of the excitation waveguide (51) and the height D1, aperture length D2, and aperture length D3 of the radiation waveguide (52).

8. The antenna according to claim 1, characterized in that: The connector (6) comprises, from top to bottom, a mounting flange (61), two connector sealing grooves (62, 63), and two waveguide coaxial converters (64, 65), wherein the mounting flange (61) has the same outer dimensions as the lower flange (24) of the metal cavity and is tightly connected so that the upper surface of the connector (6) is tightly fitted with the lower surface of the metal cavity (2); the inner wall dimensions of the waveguide of the first waveguide coaxial converter (64) are the same as the inner wall dimensions of the radiator excitation waveguide (41); and the inner wall dimensions of the waveguide of the second waveguide coaxial converter (65) are the same as the inner wall dimensions of the radiator excitation waveguide (51).

9. The antenna according to claim 1, characterized in that: The installation positions of the three sealing rings (3, 7, 8) are as follows: The first sealing ring (3) is installed in the sealing groove (21); The second sealing ring (7) is installed in the connector sealing groove (63); The third sealing ring (8) is installed in the connector sealing groove (62); The three sealing rings are used to isolate and seal the internal and external environments of the metal cavity (2) to protect the internal environment of the cavity.

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