An elevation antenna for microwave landing system

Abstract

The present invention relates to an elevation antenna for a microwave landing system, belonging to the field of microwave antenna technology. It comprises an elevation antenna unit, an isolation baffle, a coupling waveguide, a corner reflector, a support frame, and an antenna base plate. The elevation antenna units are arranged at equal intervals and mounted on the antenna base plate. The support frames are located on both sides of the elevation antenna unit, and coupling waveguides are respectively provided on the support frames on both sides. An isolation baffle is provided on each side of each elevation antenna unit. The isolation baffles, support frames, coupling waveguides on both sides of the elevation antenna unit, and the corner reflectors installed on the upper side of the coupling waveguides together form the radiation cavity of the elevation antenna unit to achieve beamforming. The present invention overcomes the problem of the prior art that a complex calibration network and beamforming structure need to be added to the antenna. At the same time, the integrated processing method is used, which simplifies the processing structure, reduces manufacturing costs, has good structural stability, and exhibits good beamforming effects and coupling characteristics within the frequency band.

Description

Technical Field

[0001] The present invention belongs to the field of navigation technology, and further relates to an elevation antenna in the field of antenna technology. The present invention can be used in a microwave landing system. Background Art

[0002] The development of microwave landing systems has always been closely linked to the overall development of aviation. As a relatively new and crucial landing device, it impacts the ability of aircraft to safely land in designated areas and protects the lives and property of the people. In recent years, with the rapid growth of the aviation industry, the expanding civil aviation user base, and the booming market demand driving the emergence of a large number of operators, the development of high-precision, high-performance microwave landing equipment has become imperative. The elevation antenna used in microwave landing systems requires channel calibration and beamforming to achieve beam coverage of the detected target. This requires the addition of a calibration network and beamforming structure within the antenna, which complicates the antenna structure and hinders miniaturization and cost reduction.

[0003] The Beijing Radio Measurement Institute disclosed a slotted waveguide, a radiating unit, a waveguide calibration network and a phased array antenna in its patent application document "A slotted waveguide, a radiating unit, a waveguide calibration network and a phased array antenna" (application number 202211611341.3, application publication number CN 116231281 A). The slotted waveguide includes a waveguide tube, in which a first feeding cavity and a second feeding cavity are provided. The first feeding cavity is located on the right side of the second feeding cavity, and two unit coupling transverse slots that pass through the first feeding cavity are provided on the right side of the front upper end of the waveguide tube. The radiating slot is located on the rear side of the coupling slot, and channel calibration is achieved by coupling energy through the coupling waveguide, and horizontal / vertical polarized waves are radiated through the radiating slot. However, the disadvantage is that the coupler couples the microwave energy in the antenna transmission waveguide through the coupling slot, rather than coupling the microwave energy radiated in the near field of the antenna. Moreover, the calibration network and radiating antenna of the antenna are independent of each other, the antenna size is large, and because the radiating antenna is compact, it is impossible to add a shaping structure around the radiating antenna, which cannot meet the requirements of elevation antenna calibration and beamforming of the microwave landing system.

[0004] The 29th Research Institute of China Electronics Technology Group Corporation (CETC) has filed a patent application titled "A Broadband Shaped Antenna Based on Multi-Turn Beamforming Radiators" (Application No. 202210948460.1, Publication No. CN 115360503 A). The patent application discloses a broadband shape-forming antenna based on multi-turn beamforming radiators. The antenna comprises a coaxial waveguide conversion unit, a rectangular waveguide conversion unit, a choke ring reflector, and a beamforming radiator connected in sequence. The beamforming radiator comprises several ring-shaped beamforming radiators. This invention addresses the problems of poor radiation performance, low power capacity, and large size that plague existing technologies. However, a disadvantage is that the antenna achieves beamforming through a beam former. For an elevation antenna for a microwave landing system composed of multiple antenna units, using a shaped radiator including several ring-shaped beamforming radiating elements as the antenna shaping structure will greatly increase the difficulty of antenna design and antenna cost. Adding an additional calibration network will further increase the complexity of the antenna structure, which cannot meet the requirements of elevation antenna calibration and beamforming in the microwave landing system.

[0005] Therefore, one of the most pressing challenges in antenna technology is designing a simple elevation antenna that can achieve beamforming and calibration. This design is expected to reduce antenna complexity while meeting the microwave landing system's requirements for simplified structure and ease of installation. Summary of the Invention

[0006] The technical problems to be solved by the present invention are:

[0007] To overcome the shortcomings of existing technologies, the present invention provides an elevation antenna for a microwave landing system. This addresses the problems of conventional antennas, such as the need for complex shaping structures and the inability of coupling calibration networks to accurately calibrate the antenna, preventing their application in low-cost, high-performance microwave landing systems.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] An elevation antenna for a microwave landing system, characterized by comprising: N elevation antenna units, 2N isolation baffles, two coupling waveguides, two corner reflectors, two support frames and an antenna base plate, where N is greater than or equal to 2;

[0010] The N elevation antenna units are arranged at equal intervals and mounted vertically on the antenna base plate; the two support frames are parallel to the elevation antenna units and located on the front and rear sides of the elevation antenna units, and a coupling waveguide is symmetrically arranged on each of the two support frames; each coupling waveguide has N coupling slots aligned with the center of the elevation antenna unit on the side facing the elevation antenna unit, coupling microwave energy to each elevation antenna unit for calibration; an isolation baffle is arranged on the left and right sides of each elevation antenna unit, and the isolation baffle, support frame, coupling waveguide and corner reflector installed on the upper side of the coupling waveguide together constitute the radiation cavity of the elevation antenna unit to achieve beamforming.

[0011] A further technical solution of the present invention: the elevation antenna unit is a metal Vivaldi antenna.

[0012] A further technical solution of the present invention is as follows: the wide side of the coupling waveguide is parallel to the antenna base plate, and the narrow side of the coupling waveguide is perpendicular to the antenna base plate.

[0013] A further technical solution of the present invention is that the coupling slots of the coupling waveguide are inclined slots, and adjacent coupling slots have opposite inclination directions.

[0014] A further technical solution of the present invention is that one end of the coupling waveguide is connected to the waveguide coaxial conversion as a coupling calibration upper port, and the other end is connected to the waveguide coaxial conversion as a coupling calibration lower port.

[0015] A further technical solution of the present invention is that the elevation antenna is processed by metal integration to ensure that the lower surface of the isolation baffle is tightly connected to the antenna base plate, and both sides of the isolation baffle are tightly connected to the support frame and the outer wall of the coupling waveguide.

[0016] A further technical solution of the present invention is that the length of the coupling waveguide is greater than the total length of the N elevation antenna units.

[0017] A further technical solution of the present invention is that the corner reflector adopts a rectangular strip structure, and the length is consistent with the length of the coupled waveguide.

[0018] The beneficial effects of the present invention are:

[0019] The elevation antenna for a microwave landing system provided by the present invention has the following advantages over the prior art:

[0020] First, the present invention uses a radiation cavity composed of an isolation baffle, a support frame, a coupling waveguide, and a corner reflector to achieve beamforming while simultaneously coupling the energy of each radiating unit through the coupling waveguide to achieve antenna calibration. The antenna adopts an integrated shaping and calibration design, using the same structure to achieve different functions. This overcomes the problem of the existing technology that requires the addition of a complex calibration network and beamforming structure within the antenna, making the present invention suitable for application scenarios of low-cost, high-performance antenna systems. The elevation antenna of the present invention is manufactured using a metal integration method. This unique design not only simplifies the manufacturing process, but also reduces the number of components, further reducing manufacturing costs, improving manufacturing efficiency, and ensuring good contact between components, thereby improving the structural stability of the antenna.

[0021] Second, the elevation antenna for a microwave landing system of the present invention improves isolation between radiating elements by adding isolation baffles between them. Furthermore, each radiating element has an independent radiation cavity, with a one-to-one correspondence between radiating elements and coupling slots. The energy of each radiating element is coupled for antenna calibration, avoiding the adverse effects of coupling with other radiating elements. Furthermore, the present invention utilizes near-field coupling to directly couple the microwave energy of the antenna elements, enabling calibration of inconsistencies in the antenna's radiating elements. This improves antenna calibration accuracy and enhances the antenna system's radiation capability, thus meeting the precise antenna calibration requirements of microwave landing systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0023] Figure 1 It is a schematic structural diagram of an elevation antenna for a microwave landing system according to the present invention;

[0024] Figure 2 is a side view of the elevation antenna structure for a microwave landing system according to the present invention;

[0025] Figure 3 This is a perspective view of the elevation antenna structure for a microwave landing system according to the present invention;

[0026] Figure 4 It is a standing wave curve diagram of the elevation antenna radiation unit for the microwave landing system of the present invention;

[0027] Figure 5 is the elevation antenna radiation pattern for the microwave landing system of the present invention;

[0028] Figure 6 is a curve diagram of the elevation antenna port isolation for the microwave landing system of the present invention;

[0029] Figure 7 It is a curve diagram of the elevation antenna coupling amplitude for the microwave landing system of the present invention. Description of the drawings:

[0031] 1- elevation antenna unit, 2- isolation baffle, 3- coupling waveguide, 4- corner reflector, 5- support frame, 6- antenna base plate, 7- coupling slot, 8- coupling calibration upper port, 9- coupling calibration lower port. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0033] The present invention proposes an elevation antenna for a microwave landing system, in which N elevation antenna units are arranged at equal intervals and installed on an antenna base plate. Support frames are located on the front and rear sides of the elevation antenna units. Coupling waveguides are respectively provided on the support frames on both sides. Each coupling waveguide has N coupling slots aligned with the center of the elevation antenna unit to couple the microwave energy of each elevation antenna unit for antenna calibration. An isolation baffle is provided on each side of each elevation antenna unit. The isolation baffles on both sides of the elevation antenna unit, the support frame, the coupling waveguide, and the corner reflector installed on the upper side of the coupling waveguide together form the radiation cavity of the elevation antenna unit to achieve beamforming.

[0034] The present invention circumvents the problem of the prior art requiring the addition of complex beam-forming structures around the antenna units, which is difficult to process and assemble. The radiation cavity, composed of an isolation baffle, a support frame, a coupled waveguide, and a corner reflector, not only achieves elevation antenna beamforming, but the coupled waveguides that make up the radiation cavity can couple the energy of the antenna units through coupling slots to achieve antenna calibration, thus circumventing the problem of the prior art requiring the addition of a complex calibration network within the antenna. The coupled waveguides of the present invention can calibrate the inconsistencies of the antenna units themselves, while the isolation baffles enhance the isolation between the radiating units, further improving the antenna calibration effect and the antenna radiation capability.

[0035] Example 1:

[0036] The application scenario of the example of the present invention is an elevation antenna for a microwave landing system, that is, an antenna array with a shaped beam and a calibration network.

[0037] Reference Figure 1The overall structure of the elevation antenna for a microwave landing system of the present invention is further described. The present invention includes N elevation antenna units 1, 2N isolation baffles 2, two coupling waveguides 3, two corner reflectors 4, two support frames 5, and an antenna base plate 6, where N ≥ 2.

[0038] Among them, the elevation antenna unit 1 is a metal Vivaldi elevation antenna unit, and the N elevation antenna units 1 are arranged at equal intervals and installed on the antenna base plate 6. The two support frames 5 are parallel to the elevation antenna unit 1 and are located on the front and back sides of the elevation antenna unit 1. A coupling waveguide 3 is set on each support frame 5, and the two coupling waveguides 3 are symmetrically distributed with the elevation antenna unit 1 as the symmetry axis. One end of the coupling waveguide 3 is connected to the waveguide coaxial conversion as the coupling calibration upper port 8, and the other end is connected to the waveguide coaxial conversion as the coupling calibration lower port 9. Each coupling waveguide 3 is provided with N coupling slots 7 aligned with the center of the elevation antenna unit 1 to couple the microwave energy of each elevation antenna unit 1 for antenna calibration. The coupling slots 7 are slanted slots, and adjacent coupling slots are tilted in opposite directions. An isolation baffle 2 is provided on each left and right side of each elevation antenna unit 1. The isolation baffles 2 on the left and right sides of the elevation antenna unit 1, the support frames 5 on the front and rear sides, the coupling waveguide 3, and the corner reflector 4 installed on the upper side of the coupling waveguide 3 together form the radiation cavity of the elevation antenna unit 1 to achieve beamforming.

[0039] Reference Figure 2 , the elevation antenna structure for the microwave landing system of the present invention is further described. Figure 2 Coupling waveguides 3 are provided on the support frames 5 on both sides of the center. The wide sides of the coupling waveguides 3 are parallel to the antenna base plate 6, and the narrow sides of the coupling waveguides 3 are perpendicular to the antenna base plate 6. The length of the coupling waveguides 3 is greater than the total length of the N elevation antenna units 1. The corner reflectors 4 are rectangular strips with the same length as the coupling waveguides 3. The elevation antenna comprises the elevation antenna units 1, isolation baffles 2, coupling waveguides 3, corner reflectors 4, support frames 5, and antenna base plate 6, all of which are integrated metal structures. These structures are manufactured using an integrated process to ensure a tight connection between the bottom surface of the isolation baffle 2 and the antenna base plate 6, and between the two sides of the isolation baffle 2 and the outer walls of the support frames 5 and coupling waveguides 3. The components are well electrically connected, resulting in excellent structural stability.

[0040] The effects of the present invention can be further illustrated by the following simulation experiments.

[0041] 1. Simulation conditions

[0042] Use High Frequency Structure Simulator simulation software to simulate Figure 1 Elevation antenna for a microwave landing system is shown.

[0043] 2. Simulation Content

[0044] Simulation 1: Figure 1 The elevation antenna for the microwave landing system shown in the figure is brought into the simulation software for simulation, and the following is obtained: Figure 3 The curve of standing wave at the radiation unit port changing with frequency is shown.

[0045] from Figure 4 It can be seen that the frequency range of the standing wave at the port of the elevation antenna radiation unit for the microwave landing system of the present invention below 1.5 is 5.03-5.09 GHz. It can be seen that the elevation antenna radiation unit of the present invention has good impedance matching characteristics.

[0046] Simulation 2: Figure 1 The elevation antenna for the microwave landing system shown in the figure is brought into the simulation software for simulation, and the following is obtained: Figure 5 The antenna radiation pattern is shown.

[0047] from Figure 5 As can be seen, the embodiment of the present invention achieves a convex beamforming effect on the antenna's H-plane through a radiation cavity composed of an isolation baffle, a support frame, a coupled waveguide, and a corner reflector. Low sidelobes are achieved on the antenna's E-plane by controlling the feed amplitude distribution at the antenna port. This demonstrates that the elevation antenna of the present invention has excellent radiation characteristics.

[0048] Simulation 3: Figure 1 The elevation antenna for the microwave landing system shown in the figure is brought into the simulation software for simulation, and the following is obtained: Figure 5 The curve of the radiation unit port isolation changing with frequency is shown.

[0049] from Figure 6 It can be seen that the embodiment of the present invention achieves a port isolation of more than 20 dB in the frequency range of 5.03 to 5.09 GHz by adding isolation baffles between the radiating units. It can be seen that the elevation antenna of the present invention has good port isolation characteristics within the frequency band.

[0050] Simulation 4: Figure 1 The elevation antenna for the microwave landing system shown in the figure is brought into the simulation software for simulation, and the following is obtained: Figure 5 The coupling calibration curves of the upper and lower ports coupling amplitude versus frequency are shown.

[0051] from Figure 7 It can be seen that the standard deviation of the coupling amplitude in the frequency range of 5.03 to 5.09 GHz is within 1.5 dB. Therefore, the elevation antenna of the present invention has good coupling characteristics within the frequency band, and can achieve precise antenna calibration.

[0052] The above simulation results show that the elevation antenna for the microwave landing system of the present invention has good impedance matching and port isolation characteristics, as well as good beamforming effect and coupling characteristics.

[0053] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. An elevation antenna for a microwave landing system, characterized in that: include: N elevation antenna units (1), 2N isolation baffles (2), 2 coupling waveguides (3), 2 corner reflectors (4), 2 support frames (5) and an antenna base plate (6), N ≥ 2; The N elevation antenna units (1) are arranged at equal intervals and vertically mounted on an antenna base plate (6); the two support frames (5) are parallel to the elevation antenna units (1) and are located on the front and rear sides of the elevation antenna units (1); a coupling waveguide (3) is symmetrically arranged on each of the two support frames (5); each coupling waveguide (3) has N coupling slots (7) aligned with the center of the elevation antenna unit (1) on the side facing the elevation antenna unit (1), coupling microwave energy to each elevation antenna unit (1) for calibration; an isolation baffle (2) is respectively arranged on the left and right sides of each elevation antenna unit (1); the isolation baffle (2), the support frame (5), the coupling waveguide (3) and a corner reflector (4) mounted on the upper side of the coupling waveguide (3) together form a radiation cavity of the elevation antenna unit (1) to achieve beamforming.

2. The elevation antenna for a microwave landing system according to claim 1, characterized in that: The elevation antenna unit (1) is a metal Vivaldi antenna.

3. The elevation antenna for a microwave landing system according to claim 1, characterized in that: The wide side of the coupling waveguide (3) is parallel to the antenna bottom plate (6), and the narrow side of the coupling waveguide (3) is perpendicular to the antenna bottom plate (6).

4. The elevation antenna for a microwave landing system according to claim 1, characterized in that: The coupling slots (7) of the coupling waveguide (3) are inclined slots, and adjacent coupling slots (7) have opposite inclined directions.

5. The elevation antenna for a microwave landing system according to claim 1, characterized in that: One end of the coupling waveguide (3) is connected to a waveguide coaxial conversion as a coupling calibration upper port (8), and the other end is connected to a waveguide coaxial conversion as a coupling calibration lower port (9).

6. The elevation antenna for a microwave landing system according to claim 1, characterized in that: The elevation antenna is processed by metal integration to ensure that the lower surface of the isolation baffle (2) is tightly connected to the antenna bottom plate (6), and both sides of the isolation baffle (2) are tightly connected to the support frame (5) and the outer wall of the coupling waveguide (3).

7. The elevation antenna for a microwave landing system according to claim 1, characterized in that: The length of the coupling waveguide (3) is greater than the total length of the N elevation antenna units (1).

8. The elevation antenna for a microwave landing system according to claim 1, characterized in that: The corner reflector (4) adopts a rectangular strip structure, and its length is consistent with the length of the coupling waveguide (3).

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