A light and thin gap waveguide antenna and an antenna array based thereon

Abstract

The application discloses a light and thin slot waveguide antenna, which comprises a radiation waveguide and a feed waveguide, the radiation waveguide and the feed waveguide share a bottom plate of the radiation waveguide, a coupling slot is etched on the bottom plate, and the transmission of microwave signals between the feed waveguide and the radiation waveguide is realized through the coupling slot; the length direction of the radiation waveguide is along the azimuth direction of the antenna, the length direction of the feed waveguide is along the elevation direction of the antenna, the radiation waveguide and the feed waveguide are arranged orthogonally, and the feed waveguide is located below the radiation waveguide. The light and thin slot waveguide antenna can realize an inclined beam and has the advantages of light weight and easy arraying.

Description

Technical Field

[0001] This invention belongs to the field of microwave antenna technology, and particularly relates to an antenna array based on a thin and light slot waveguide antenna. Background Technology

[0002] In satellite navigation and mobile communications, targets located at an angle often require antennas with tilted beams. Besides the traditional method of mechanically rotating the antenna, tilted beams are currently mainly achieved through multi-beam antenna arrays, pattern-reconfigurable antennas, and array antenna pattern synthesis. However, the large size and complex feeding networks of array antennas limit their application. Tilted beamforming antennas with specially designed structures overcome these drawbacks, significantly reducing antenna size and weight. Therefore, researchers have conducted in-depth studies on the integrated design of antennas and beam tilting.

[0003] Common beam-tilted antenna elements include microstrip magnetic Yagi antennas, quasi-Yagi dipoles, and asymmetric microstrip spiral antennas. Microstrip magnetic Yagi antennas and quasi-Yagi dipoles utilize the principle of Yagi antennas, adding reflective and directing structures to the main radiator. Individual antenna elements are relatively large, and satellite and communication systems typically require arrays of these elements to achieve high gain, making large-aperture Yagi antennas unsuitable. Asymmetric microstrip spiral antennas, on the other hand, are difficult to manufacture and lack structural stability.

[0004] Waveguide slot antennas are highly efficient and compact antennas widely used in radar and microwave communication systems. Waveguide slot antennas mainly come in two slot types: wide-side slots and narrow-side slots. Currently, the commonly used wide-side slots are staggered along the centerline of the wide side of the waveguide. However, when these slots deviate significantly from the centerline, it can lead to poor cross-polarization and the generation of parasitic sidelobes. Another common type of wide-side slot is distributed along the centerline of the wide side of the waveguide, with perturbation blocks staggered on both sides of the slots. This type of slot waveguide antenna requires high precision in fabrication and welding, and also adds extra weight. Another type is the traveling-wave waveguide slot antenna, where the electromagnetic waves within the waveguide propagate approximately like traveling waves. The antenna can maintain good matching over a wide frequency band, and the beam pointing of the antenna varies with frequency. This type of waveguide is typically implemented by increasing its length when assembling the antenna array, which places high demands on the consistency of fabrication. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a lightweight slotted waveguide antenna. A coupling slot is etched onto the substrate, enabling microwave signal transmission between the feed waveguide and the radiating waveguide. The length of the radiating waveguide is along the azimuth direction of the antenna, and the length of the feed waveguide is along the elevation direction of the antenna. The radiating and feed waveguides are arranged orthogonally. The feed waveguide is located below the radiating waveguide.

[0006] Furthermore, the radiating waveguide includes several identical parallel radiating waveguide cavities, with adjacent radiating waveguide cavities sharing a sidewall. The upper surface of each radiating waveguide cavity is provided with a row of antenna radiating slots, and each row of antenna radiating slots has 2n radiating slots arranged at equal intervals. The centerline of each row of antenna radiating slots is arranged along the longitudinal symmetry line of the radiating waveguide cavity, where n is a positive integer greater than or equal to 1. The longitudinal centerline of the feed waveguide is located between the (n-1)th and nth radiating slots along the length of the radiating waveguide.

[0007] Furthermore, each radiating waveguide cavity has a ridge structure on its base plate along a symmetrical line along the longitudinal direction of the cavity. Several alternating matching blocks, which are arc-shaped, are arranged on the two side walls of the cavity. The matching blocks are positioned in the same location within each cavity. By adjusting the cross-sectional dimensions of the cavity and the height of the ridge structure, the spacing between adjacent radiating slots in a row of antenna radiating slots is made to be half a waveguide wavelength. The length of each radiating slot is greater than half the wavelength corresponding to the antenna's operating frequency.

[0008] Furthermore, the height of the matching block is the same as the height of the radiating waveguide cavity, and the center of the matching block is located on the center line perpendicular to the antenna radiating slot. By adjusting the width of the matching block, the amplitude and phase of the electromagnetic field signal radiated by a row of 2n radiating slots are made consistent.

[0009] Furthermore, the feeding waveguide includes a feeding port, a coupling port, and a feeding waveguide cavity. The feeding port and the coupling port are located at both ends of the bottom surface of the feeding waveguide cavity. The feeding port and the coupling port are coaxial. The outer conductors of the feeding port and the coupling port are welded to the feeding waveguide cavity. The inner conductors of the feeding port and the coupling port extend into the feeding waveguide cavity. By adjusting the length of the inner conductors of the feeding port and the coupling port extending into the feeding waveguide cavity, impedance matching between the feeding port and the coupling port is achieved.

[0010] Furthermore, each coupling slot passes through the ridge structure of the radiating waveguide and divides the ridge structure into two segments; several coupling slots rotate in opposite directions in sequence, and two adjacent coupling slots form a figure-eight shape; the length of the coupling slot is greater than half of the wavelength corresponding to the antenna operating frequency.

[0011] Furthermore, when the antenna is in the transmitting state, the electromagnetic wave signal enters the feed waveguide cavity from the feed port, and then enters the parallel-arranged radiation waveguide cavities sequentially through the coupling slots. Finally, a small portion of the electromagnetic wave signal enters the coupling port. By setting the size of the feed waveguide cavity and the rotation angle of the coupling slots, the phase of the signal entering the radiation waveguide cavity through the coupling slots is sequentially delayed. The electromagnetic wave signal entering the radiation waveguide cavity is radiated to the external space through the antenna radiation slots, thereby giving the antenna a tilted beam in the pitch direction.

[0012] Furthermore, the matching block and ridge structure in the radiating waveguide are directly machined in the radiating waveguide cavity. The top plate on the upper surface of the radiating waveguide cavity is first machined with radiating slots, and then welded to the lower cavity of the radiating waveguide cavity. Finally, the radiating waveguide and the feed waveguide are integrated and welded together.

[0013] The present invention also provides an antenna array, which is composed of at least three of the above-mentioned antennas. The feed waveguides of the first and third antennas are in the same position, and the longitudinal centerline of the feed waveguide is located in the middle of the (n-1)th and nth radiating slots in the length direction of the radiating waveguide. The longitudinal centerline of the feed waveguide of the second antenna is located in the middle of the (n+1)th and (n+2)th radiating slots in the length direction of the radiating waveguide, and so on for the remaining antennas.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. Small size and light weight: The antenna of this invention is designed with an integrated radiating waveguide and a feeding waveguide, which is compact in structure. The two waveguide cavities share the same waveguide wall and are integrally processed, which further reduces the weight of the antenna.

[0016] 2. Easy to integrate and simple to process: The antenna of this invention adopts a modular design and processing, which is very suitable for arranging and combining into an antenna array. Modularization reduces the processing difficulty of the antenna, improves the antenna processing yield, and greatly reduces the processing cost.

[0017] 3. Excellent beam pattern performance: The radiation slot of this invention is located on the centerline of the waveguide cavity, resulting in low beam cross-polarization. This invention uses a fed waveguide for coupling feeding, achieving large-angle beam tilt without the need for an additional phase shifter. Attached Figure Description

[0018] Figure 1 This is an overall appearance view of the antenna according to an embodiment of the present invention.

[0019] Figure 2 This is a side cross-sectional view of the antenna according to an embodiment of the present invention.

[0020] Figure 3 This is a top perspective view of the antenna according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of the feed waveguide cavity structure according to an embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of the feed waveguide cavity and coupling gap in an embodiment of the present invention.

[0023] Figure 6 This is a schematic diagram of the radiation waveguide cavity structure according to an embodiment of the present invention.

[0024] Figure 7 This is a bottom-view structural diagram of the antenna array of the three antenna combinations in an embodiment of the present invention.

[0025] Figure 8 This is the normalized radiation pattern result of the antenna in the elevation direction according to an embodiment of the present invention.

[0026] Figure 9 The image shows the normalized radiation pattern of the antenna array after combining three antennas in an embodiment of the present invention in the elevation direction.

[0027] In the picture:

[0028] Radiation waveguide 1, feed waveguide 2, antenna radiation slot 11, ridge structure 12, radiation waveguide coupling slot 13, base plate 14, radiation waveguide cavity 15, first cavity 151, second cavity 152, third cavity 153, fourth cavity 154, matching block 16, feed port 21, coupling port 22, feed waveguide cavity 23, first antenna 31, second antenna 32, third antenna 33. Detailed Implementation

[0029] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0031] It is understood that the terms “first,” “second,” etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. Spatial relation terms such as “below,” “under,” “below,” “below,” “under,” “above,” “above,” etc., may be used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as “below” or “under” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0032] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is an exchange of electrical signals or data between the connected objects. When used herein, the singular forms "a," "an," and "the" may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprising / including" or "having," etc., specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term "and / or" as used in this specification includes any and all combinations of the associated listed items.

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] The purpose of this invention is to provide a slot waveguide antenna with tilted beams, which features high integration, light weight, and easy array integration.

[0035] like Figure 1 and Figure 2As shown, this embodiment provides a lightweight slotted waveguide antenna, including a radiating waveguide 1 and a feeding waveguide 2. The base plate 14 of the radiating waveguide 1 and the upper surface of the feeding waveguide 2 adopt a common wall design, and the transmission of microwave signals between the feeding waveguide 2 and the radiating waveguide 1 is realized by coupling slots 13 etched on the base plate 14.

[0036] The radiating waveguide 1 in this embodiment includes four identical parallel radiating waveguide cavities 15, including a first cavity 151, a second cavity 152, a third cavity 153, and a fourth cavity 154. Each radiating waveguide cavity 15 is a cuboid metal cavity structure, with adjacent radiating waveguide cavities 15 sharing a common side metal wall. Each radiating waveguide cavity 15 has a row of antenna radiation slots 11 on its upper surface. Each row of antenna radiation slots 11 has several radiation slots spaced at equal intervals, and the centerline of each row of antenna radiation slots 11 is arranged along a line of symmetry in the longitudinal direction of the radiating waveguide cavity 15.

[0037] To reduce the size of the waveguide cavity, a ridge structure 12 is provided on the base plate 14 of each radiating waveguide cavity 15 along the longitudinal symmetry line of the radiating waveguide cavity 15. Several alternating matching blocks 16 are provided on the two side walls of the radiating waveguide cavity 15, and the matching blocks 16 are arc-shaped. The matching blocks 16 are uniformly distributed in each radiating waveguide cavity 15. By optimizing the cross-sectional dimensions of the radiating waveguide cavity 15 and the height of the ridge structure 12, the spacing between adjacent radiating slots in a row of antenna radiating slots 11 is half a waveguide wavelength. Typically, the sum of "the width of the cross-section of the waveguide cavity (15) + the height of the ridge structure (12)" is designed to be slightly greater than half the wavelength corresponding to the operating frequency. The length of each radiating slot is slightly greater than half the wavelength corresponding to the antenna operating frequency. The height of the matching block 16 is the same as the height of the radiating waveguide cavity 15, and the center of the matching block 16 is located on the center line perpendicular to the center line of the antenna radiating slot 11. By optimizing the width of the matching block 16, the amplitude and phase of the electromagnetic field signal radiated by the row of 8 radiating slots are consistent.

[0038] like Figure 4 As shown, the feeding waveguide 2 in this embodiment includes a feeding port 21, a coupling port 22, and a feeding waveguide cavity 23. The feeding port 21 and the coupling port 22 are located at both ends of the bottom surface of the feeding waveguide cavity 23. The feeding port 21 and the coupling port 22 are coaxial. The outer conductors of the feeding port 21 and the coupling port 22 are welded to the feeding waveguide cavity 23, and the inner conductors of the feeding port 21 and the coupling port 22 extend into the feeding waveguide cavity 23. By adjusting the length of the inner conductors of the feeding port 21 and the coupling port 22 extending into the feeding waveguide cavity 23, impedance matching between the feeding port 21 and the coupling port 22 is achieved.

[0039] like Figure 3As shown, the thin and light slotted waveguide antenna described in this embodiment is integrally fabricated and welded from a radiating waveguide 1 and a feeding waveguide 2. The matching block 16 and ridge structure 12 in the radiating waveguide 1 are directly machined within the radiating waveguide cavity 15. The top plate on the upper surface of the radiating waveguide cavity 15 is first machined with radiating slots and then welded to the lower cavity of the radiating waveguide cavity 15. The length direction of the radiating waveguide 1 is aligned with the azimuth direction of the antenna, and the length direction of the feeding waveguide 2 is aligned with the elevation direction of the antenna. The radiating waveguide 1 and the feeding waveguide 2 are arranged orthogonally. The feeding waveguide 2 is located below the radiating waveguide 1, and the longitudinal centerline of the feeding waveguide 2 is located between the third and fourth radiating slots along the length direction of the radiating waveguide 1.

[0040] As shown in the schematic diagram of the feed waveguide 2 in this embodiment ( Figure 4 As shown in the figure, the feed waveguide cavity 23 is a rectangular metal waveguide structure. A hollow area is provided in the middle of the upper surface of the feed waveguide 2, where it contacts the radiating waveguide 1, to facilitate welding the feed waveguide 2 and the radiating waveguide 1 after assembly. Figure 5 As shown, the base plate 14 of the radiating waveguide 1 and the hollow area of ​​the feeding waveguide 2 are fitted together so that the radiating waveguide 1 and the feeding waveguide 2 share the same base plate 14.

[0041] like Figure 3 He Ru Figure 6 As shown, four coupling slots 13 are provided on the base plate 14. The coupling slots 13 pass through the ridge structure 12 of the radiation waveguide 1 and divide the ridge structure 12 into two segments. The four coupling slots rotate in opposite directions in sequence, forming two sets of figure-eight shapes. The length of the coupling slots 13 is slightly greater than half the wavelength corresponding to the antenna operating frequency. When the antenna is in the transmitting state, the electromagnetic wave signal enters the feed waveguide cavity 23 from the feed port 21. The electromagnetic wave signal enters the first cavity 151, the second cavity 152, the third cavity 153, and the fourth cavity 154 in sequence through the coupling slots 13, and finally the remaining small part of the electromagnetic wave signal enters the coupling port 22. By setting the size of the feed waveguide cavity 23 and the rotation angle of the coupling slots 13, the phase of the signal entering the four radiation waveguide cavities 15 through the coupling slots 13 is sequentially delayed. The electromagnetic wave signal entering the radiation waveguide cavity 15 is radiated to the external space through the antenna radiation slots 11, and the antenna has a tilted beam in the elevation direction.

[0042] This embodiment also provides an antenna array composed of the above-described antennas, such as... Figure 7As shown, when the three antennas are combined into an array, the feed waveguides 2 of the first antenna 31 and the third antenna 33 are positioned in the same direction, with the longitudinal centerline of the feed waveguide 2 located between the third and fourth radiating slots along the length of the radiating waveguide 1. The longitudinal centerline of the feed waveguide 2 of the second antenna 32 is located between the fifth and sixth radiating slots 11 along the length of the radiating waveguide 1, and so on for the remaining antenna elements. Thus, after the array is formed, the feed waveguides 2 of all antennas are located below the radiating waveguide 1. This modular combination structure is compact and has a high degree of integration.

[0043] Figure 8 This is the antenna radiation pattern in the elevation direction of the embodiment, with the antenna beam pointing at +45°. Figure 9 This is the elevation pattern of the array after combining three antennas. The beam pointing of the antenna array is +45°.

[0044] The significant advantages of this invention are:

[0045] 1. Small size and light weight: The antenna of this invention is designed with an integrated radiating waveguide and a feeding waveguide, which is compact in structure. The two waveguide cavities share the same waveguide wall and are integrally processed, which further reduces the weight of the antenna.

[0046] 2. Easy to integrate and simple to process: The antenna of this invention adopts a modular design and processing, which is very suitable for arranging and combining into an antenna array. Modularization reduces the processing difficulty of the antenna, improves the antenna processing yield, and greatly reduces the processing cost.

[0047] 3. Excellent beam pattern performance: The radiation slot of this invention is located on the centerline of the waveguide cavity, resulting in low beam cross-polarization. This invention uses a fed waveguide for coupling feeding, achieving large-angle beam tilt without the need for an additional phase shifter.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight and thin slot waveguide antenna, characterized in that, The system includes a radiating waveguide (1) and a feeding waveguide (2), which share a base plate (14) of the radiating waveguide (1). A coupling slot (13) is etched on the base plate (14) to enable the transmission of microwave signals between the feeding waveguide (2) and the radiating waveguide (1). The length direction of the radiating waveguide (1) is along the azimuth direction of the antenna, and the length direction of the feeding waveguide (2) is along the elevation direction of the antenna. The radiating waveguide (1) and the feeding waveguide (2) are arranged orthogonally. The feeding waveguide (2) is located below the radiating waveguide (1). The radiating waveguide (1) contains... The system comprises several identical parallel radiating waveguide cavities (15), with adjacent radiating waveguide cavities (15) sharing a sidewall. Each radiating waveguide cavity (15) has a row of antenna radiating slots (11) on its upper surface. Each row of antenna radiating slots (11) has 2n radiating slots spaced at equal intervals. The center line of each row of antenna radiating slots (11) is set along the longitudinal symmetry line of the radiating waveguide cavity (15), where n is a positive integer greater than or equal to 1. The longitudinal center line of the feed waveguide (2) is located between the (n-1)th and nth radiating slots in the length direction of the radiating waveguide (1).

2. The thin and light slotted waveguide antenna according to claim 1, characterized in that, Each radiating waveguide cavity (15) has a ridge structure (12) arranged on the base plate (14) along the longitudinal symmetry line of the radiating waveguide cavity (15). Several alternating matching blocks (16) are arranged on the two side walls of the radiating waveguide cavity (15). The matching blocks (16) are arc-shaped. The matching blocks (16) are uniformly distributed in each radiating waveguide cavity (15). By adjusting the cross-sectional size of the radiating waveguide cavity (15) and the height of the ridge structure (12), the spacing between adjacent radiating slots in a row of antenna radiating slots (11) is half a waveguide wavelength. The length of each radiating slot is greater than half of the wavelength corresponding to the antenna operating frequency.

3. The thin and light slotted waveguide antenna according to claim 2, characterized in that, The height of the matching block (16) is the same as the height of the radiation waveguide cavity (15). The center of the matching block (16) is located on the center line perpendicular to the antenna radiation slot (11). By adjusting the width of the matching block (16), the amplitude and phase of the electromagnetic field signal radiated by a row of 2n radiation slots are made consistent.

4. The thin and light slotted waveguide antenna according to claim 1, characterized in that, The feeding waveguide (2) includes a feeding port (21), a coupling port (22), and a feeding waveguide cavity (23). The feeding port (21) and the coupling port (22) are located at both ends of the bottom surface of the feeding waveguide cavity (23). The feeding port (21) and the coupling port (22) are coaxial. The outer conductors of the feeding port (21) and the coupling port (22) are welded to the feeding waveguide cavity (23). The inner conductors of the feeding port (21) and the coupling port (22) extend into the feeding waveguide cavity (23). By adjusting the length of the inner conductors of the feeding port (21) and the coupling port (22) extending into the feeding waveguide cavity (23), impedance matching of the feeding port (21) and the coupling port (22) is achieved.

5. The thin and light slotted waveguide antenna according to claim 4, characterized in that, Each coupling slot (13) passes through the ridge structure (12) of the radiating waveguide (1) and divides the ridge structure (12) into two segments; several coupling slots (13) rotate in opposite directions in sequence, and two adjacent coupling slots (13) form a figure-eight shape; the length of the coupling slot (13) is greater than half of the wavelength corresponding to the antenna operating frequency.

6. The thin and light slotted waveguide antenna according to claim 5, characterized in that, When the antenna is in the transmitting state, the electromagnetic wave signal enters the feeding waveguide cavity (23) from the feeding port (21), and the electromagnetic wave signal enters the parallel-arranged radiation waveguide cavity (15) through the coupling gap (13) in sequence. Finally, the remaining small part of the electromagnetic wave signal enters the coupling port (22). By setting the size of the feed waveguide cavity (23) and the rotation angle of the coupling slot (13), the phase of the signal entering the radiation waveguide cavity (15) through the coupling slot (13) is sequentially delayed; the electromagnetic wave signal entering the radiation waveguide cavity (15) is radiated to the external space through the antenna radiation slot (11), thereby making the antenna have a tilted beam in the pitch direction.

7. The thin and light slotted waveguide antenna according to claim 2, characterized in that, The matching block (16) and ridge structure (12) in the radiation waveguide (1) are directly machined in the radiation waveguide cavity (15). The top plate on the upper surface of the radiation waveguide cavity (15) is first machined with radiation slots, and then welded to the lower cavity of the radiation waveguide cavity (15). Finally, the radiation waveguide (1) and the feed waveguide (2) are integrally machined and welded together.

8. An antenna array, characterized in that, It is composed of at least three thin slot waveguide antennas as described in any one of claims 1-7. The feed waveguides (2) of the first and third antennas are in the same position, and the longitudinal centerline of the feed waveguide (2) is located in the middle of the (n-1)th and nth radiating slots in the length direction of the radiating waveguide (1). The longitudinal centerline of the feed waveguide (2) of the second antenna is located in the middle of the (n+1)th and (n+2)th radiating slots in the length direction of the radiating waveguide, and so on for the remaining antennas.

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