Multi-beam antenna and beam scanning feed structure

Abstract

The invention relates to the technical field of two-dimensional multi-beam antennas, in particular to a multi-beam antenna and a beam scanning feed structure. The structure comprises a cylindrical luneberg lens and a feed source unit. The two feed source units in pairs located at the same direction angle are sequentially synthesized into an input port through the non-contact power divider, and the non-contact power divider comprises an input end waveguide section and a gap waveguide section; by mechanically moving the non-contact feed network on the pitching surface of the structure, the path length from the input port to the feed source unit can be changed, so that the phase of the feed source unit is adjusted, and rapid mechanical scanning of the pitching surface is realized; the problems that the scanning speed is low and beam scanning is difficult to achieve by a fixed feed network due to the fact that a plurality of phase shifters are needed in electric control scanning are solved. In combination with azimuth plane multi-beam scanning and pitching plane beam scanning, two-dimensional multi-beam coverage can be realized, and the feed source antenna placement number and the radiation beam number are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of two-dimensional multi-beam antennas, and in particular to a multi-beam antenna and a beam scanning feeding structure. Background Art

[0002] As the frequency increases to the terahertz band, the antenna size is further reduced, and the difficulty of arranging multiple feed antennas of the space-fed antenna system, including lens antennas or reflector antennas, increases, making it difficult to achieve two-dimensional multi-beam large-angle radiation. Existing multi-beam lens antennas mainly use mechanical movement scanning of a single feed antenna or multi-feed excitation radiation, but the number of beams is limited and the scanning range is small. The Luneburg lens has the advantage of large-angle multi-beam radiation, but there are currently few reports on multi-beam Luneburg lens antennas in the terahertz band, and they are limited to one-dimensional multi-beam radiation in the azimuth plane. The realization of beam scanning in the elevation plane is a difficult problem that needs to be solved. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide a multi-beam antenna and a beam scanning feeding structure, which can realize multi-beam radiation in a two-dimensional space.

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is: a multi-beam antenna and a beam scanning feeding structure, the structure comprising a cylindrical Luneburg lens and a plurality of feed source units partially arranged around the periphery of the cylindrical Luneburg lens in the coaxial direction with the cylindrical Luneburg lens;

[0005] The two feed source units in pairs located at the same direction angle are sequentially combined into an input port through a non-contact power divider to construct a non-contact feeding network, wherein the non-contact power divider includes an input end waveguide segment and a gap waveguide segment, and the two output ends of the gap waveguide segment are respectively connected to the input end of the feed source unit through a vertically arranged switching structure waveguide segment;

[0006] There is a height difference between the transition structure waveguide section and the gap waveguide section, forming a stepped structure;

[0007] By mechanically moving the non-contact feeding network on the pitch plane of the structure, the path length from the input port to the feed source unit can be changed, thereby adjusting the phase of the feed source unit to achieve multi-beam scanning on the vertical pitch plane;

[0008] The non-contact power divider is designed based on a gap waveguide, the gap waveguide section includes a bottom metal and a top metal and a plurality of unit metal columns spaced apart on the bottom metal, and the non-contact power divider realizes non-contact mechanical movement through an air gap between the top metal and the unit metal columns.

[0009] Furthermore, two pairs of the feed units located at the same direction angle are sequentially synthesized into M-level input ports through M-level non-contact power dividers, and starting from the first M-level input port, the M-level input ports of two adjacent layers are synthesized into M-1-level input ports through M-1-level non-contact power dividers, and so on until they are synthesized into a first-level input port.

[0010] Furthermore, the two feed units in pairs located at the same direction angle are sequentially synthesized into sub-arrays through a waveguide power divider, and starting from the first synthesized sub-array, the sub-arrays of two adjacent layers are synthesized into input ports through the non-contact power divider.

[0011] Furthermore, the input-end waveguide is connected to the gap waveguide section via a matching diaphragm, and the shape and size of the matching diaphragm are adjusted according to the working bandwidth requirements of the feed unit.

[0012] Furthermore, the cylindrical Luneburg lens has a total of N layers, the inner N-2 layers adopt a dielectric ring unit structure, and the outermost two layers adopt a discrete dielectric column unit structure. The outermost two discrete dielectric ring unit structures are connected as a whole through dielectric rings, and then the ten-layer structure is connected through radial dielectric rods to form an overall lens structure.

[0013] Furthermore, the input ends of the plurality of feed units formed by rotation on the azimuth plane are converted to input ends located on the same plane via a curved waveguide.

[0014] Compared with the existing technology, this solution has the following significant advantages:

[0015] This solution achieves fast mechanical scanning of the pitch plane, solving the problem of slow scanning speed caused by the need to use multiple phase shifters for electronically controlled scanning and the difficulty of achieving beam scanning with a fixed feed network. The use of a non-contact power divider in the form of a gap waveguide to waveguide reduces channel switching loss and complexity. The feed units at different azimuth positions are converted to the input port in the same plane through the feed channel, which improves the switching speed of different feed excitations and reduces the volume of the feed array. Combining multi-beam in the azimuth plane and beam scanning in the pitch plane, two-dimensional multi-beam coverage can be achieved, effectively increasing the number of feed antenna placements and the number of radiation beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 It is a schematic diagram of the overall structure of the multi-beam antenna in the present invention;

[0018] Figure 2is a top view of the multi-beam antenna of the present invention;

[0019] Figure 3 is a side view of the feeding structure of the present invention;

[0020] Figure 4 Schematic diagram of the structure of a cylindrical Luneburg lens;

[0021] Figure 5 It is a schematic diagram of the structure of the sub-array;

[0022] Figure 6 It is a structural schematic diagram of a contactless power divider;

[0023] Figure 7 is a schematic diagram of the structure of a waveguide power divider;

[0024] Figure 8 It is a schematic diagram of the structure of the vertical transition from gap waveguide to waveguide;

[0025] Fig. 9 is a schematic structural diagram of a gap waveguide structure and a gap waveguide unit;

[0026] Fig.10 Schematic diagram of the pitch beam scanning direction in this embodiment;

[0027] Fig.11 This is a schematic diagram of the azimuth multi-beam radiation direction in this embodiment;

[0028] Fig.12 Schematic diagram of impedance matching in this embodiment;

[0029] In the figure: 1-cylindrical Luneburg lens, 2-feed source unit, 3-feed network, 4-primary input port, 5-bent waveguide, 6-waveguide input end plane, 7-waveguide power divider, 8-primary contactless power divider, 9-secondary contactless power divider, 10-gap waveguide to waveguide transition structure, 11-dielectric ring unit structure, 12-dielectric column unit structure, 13-dielectric ring, 14-dielectric rod, 15-first subarray, 16-second subarray, 17-third sub-array, 18-fourth sub-array, 19-first and second-level input ports, 20-second and second-level input ports, 21-matching diaphragm, 22 / 30-output end waveguide section / gap waveguide section, 23-input end waveguide section, 24-top metal, 25-bottom metal, 26-unit metal column, 27-waveguide at input end of waveguide power divider, 28-waveguide at output end of waveguide power divider, 29-transfer structure waveguide section, 31-gap waveguide unit. DETAILED DESCRIPTION

[0030] The preferred examples of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred examples described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0031] like Figure 1-9 As shown, the multi-beam antenna and beam scanning feeding structure described in the present invention include a cylindrical Luenburg lens 1 and a plurality of feed units 2 which are partially arranged around the periphery of the cylindrical Luenburg lens 1 in the coaxial direction with the cylindrical Luenburg lens 1. In the present embodiment, the feed unit 2 is a feed horn.

[0032] In this embodiment, the cylindrical Luneburg lens 1 is radially distributed with a total of ten layers. The actual processing model takes the problem of removing printing supports into consideration. A dielectric ring unit structure 11 is used in the inner eight layers. A discrete dielectric column unit structure 12 is used in the outermost two layers in consideration of processing accuracy and molding size. The two outermost discrete dielectric ring unit structures 11 are connected as a whole through a dielectric ring 13, and then the ten-layer structure is connected through a radial dielectric rod 14 to form an overall lens structure. The structure composed of the dielectric ring 13 and the dielectric rod 14 is a connecting structure, which helps to achieve integrated processing of the lens.

[0033] In this embodiment, the input ends of the multiple feeding horns formed by rotation on the azimuth plane are converted to the input ends located in the same plane, that is, the waveguide input end plane 6, through the curved waveguide 5. Starting from the first layer of feeding horns, the feeding horns of two adjacent layers located at the same azimuth angle are successively combined into sub-arrays through the waveguide power divider 7, and the waveguide power divider 7 includes a waveguide 27 at the input end of the waveguide power divider and a waveguide 28 at the output end of the waveguide power divider located at both ends. In this embodiment, the first sub-array 15, the second sub-array 16, the third sub-array 17 and the fourth sub-array 18 are successively included. Starting from the first sub-array, the sub-arrays of the adjacent two layers are successively combined into M-level input ports through the M-level non-contact power divider. It can be seen that in this embodiment, the first sub-array 15 and the second sub-array 16 are combined into the first and second-level input ports 19 through the first-level non-contact power divider 8, and the third sub-array 17 and the fourth sub-array 18 are combined into the second and second-level input ports 20. Starting from the first M-level input port, the adjacent M-level input ports are combined into an M-1-level input port through an M-1-level contactless power divider, and so on until they are combined into a primary input port 4. In this embodiment, the first secondary input port 19 and the second secondary input port 20 are combined into a primary input port 4 through a secondary contactless power divider 9. The two-level contactless power divider and the primary input port 4 in this embodiment together constitute a contactless feeding network.

[0034] The non-contact power dividers 8 from M to the first level all include an input end waveguide section 23 and an output end waveguide section, namely, a gap waveguide section 22 / 30. The two output ends of the gap waveguide section 22 / 30 are respectively connected to the input end of the feed source unit 2 through a vertically arranged switching structure waveguide section 29, and there is a height difference between the switching structure waveguide section 29 and the gap waveguide section 22 / 30, forming a stepped structure, such as Figure 3As shown, a stepped gap waveguide to waveguide transition structure 10 is formed.

[0035] Therefore, by mechanically moving the contactless feeding network on the pitch plane of the structure, the path length from the input port to the feed unit 2 can be changed, and then the phase of the feed unit 2 can be adjusted to achieve multi-beam scanning on the vertical pitch plane.

[0036] Furthermore, the non-contact power divider 8 / 9 is designed based on the gap waveguide, and the gap waveguide section 30 includes a bottom metal 25 and a top metal 24 and a plurality of unit metal pillars 26 spaced apart on the bottom metal 25, and a single unit metal pillar 26 constitutes a gap waveguide unit 31. The non-contact power divider 8 / 9 realizes non-contact mechanical movement through the air gap between the top metal 24 and the unit metal pillar 26.

[0037] The input waveguide section 23 is connected to the gap waveguide section 22 / 30 through the matching diaphragm 21. In this embodiment, the matching diaphragm 21 is triangular and connected to the top metal 24 as a whole, and can move simultaneously. The shape and size of the matching diaphragm 21 can be adjusted to adjust the impedance distribution of the non-contact power divider 8 / 9. The specific shape and size of the matching diaphragm 21 can be adjusted according to the working bandwidth requirements of the feed unit 2. The shape of the matching diaphragm 21 is not necessarily a triangle, but can also be other shapes such as a rectangle, a trapezoid, a step type, etc.

[0038] Therefore, in this solution, the feed array at the same azimuth angle includes a feed unit 2 and a feed network 3, and the feed network 3 includes the input end from the feed unit 2 to the input end of the entire feed array.

[0039] Mechanically moving the first and second input ports 19 and the second and second input ports 20, as well as the first input port 4, along the vertical direction can change the path length from the first input port 4 to each subarray, thereby adjusting the phase of the first subarray 15 to the fourth subarray 18, thereby achieving beam scanning in the vertical direction on the elevation plane. Fig.10 The figure shows a schematic diagram of the beam scanning direction in the elevation plane in this embodiment. For the eight-layer feeding structure at different azimuth angles in this embodiment, by moving the primary and secondary input ports on the elevation plane respectively, the multi-beam radiation of the antenna in two-dimensional space can be realized. Fig.11 Schematic diagram of the multi-beam radiation direction in the azimuth plane in this embodiment. Fig.12 It is a schematic diagram of impedance matching in this embodiment.

[0040] In addition, the diameter of the cylindrical Luenburg lens 1 can be increased so that more feed arrays 2 can be arranged on its azimuth plane to achieve higher gain and larger-scale multi-beam radiation. The height of the cylindrical Luenburg lens 1 can also be increased, thereby increasing the number of sub-arrays in the subsequent structure, and more feed networks 3 are also required to connect, so as to achieve larger-scale multi-beam radiation. For example, if the height of the cylindrical Luenburg lens 1 in this embodiment is doubled, then the number of sub-arrays will also be doubled, and the eight layers in the upper part and the eight layers in the lower part need to be synthesized into four sub-arrays, and finally synthesized to the primary input port 4 through the non-contact power divider 8. Then the primary input ports 4 of the upper and lower parts need to be combined to the same input end by a non-contact power divider 8.

[0041] In this embodiment, the diameter of the cylindrical Luneburg lens 1 is 15 mm, the total height is 16 mm, the aperture of the feed horn is 2.54 mm×1.5 mm, the length is 1.6 mm, the waveguide mouth is 2.54×1.27 mm, the impedance bandwidth is greater than 30%, the elevation beam scanning angle range is greater than ±10°, and the azimuth multi-beam coverage range is ±70°.

[0042] This solution achieves fast mechanical scanning of the pitch plane, solving the problem of slow scanning speed caused by the need to use multiple phase shifters for electronically controlled scanning and the difficulty of achieving beam scanning with a fixed feed network. The use of a non-contact power divider in the form of a gap waveguide to waveguide reduces channel switching loss and complexity. The feed units at different azimuth positions are converted to the input port in the same plane through the feed channel, which improves the switching speed of different feed excitations and reduces the volume of the feed array. Combining multi-beam in the azimuth plane and beam scanning in the pitch plane, two-dimensional multi-beam coverage can be achieved, effectively increasing the number of feed antenna placements and the number of radiation beams.

[0043] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-beam antenna and a beam scanning feeding structure, characterized in that: The structure comprises a cylindrical Luneburg lens and a plurality of feed source units partially arranged around the outer periphery of the cylindrical Luneburg lens in the same axial direction as the cylindrical Luneburg lens; The two feed source units in pairs located at the same direction angle are sequentially combined into an input port through a non-contact power divider to construct a non-contact feeding network, wherein the non-contact power divider includes an input end waveguide segment and a gap waveguide segment, and the two output ends of the gap waveguide segment are respectively connected to the input end of the feed source unit through a vertically arranged switching structure waveguide segment; There is a height difference between the transition structure waveguide section and the gap waveguide section, forming a stepped structure; By mechanically moving the non-contact feeding network on the pitch plane of the structure, the path length from the input port to the feed source unit can be changed, thereby adjusting the phase of the feed source unit to achieve multi-beam scanning on the vertical pitch plane; The non-contact power divider is designed based on a gap waveguide, the gap waveguide section includes a bottom metal and a top metal and a plurality of unit metal columns spaced apart on the bottom metal, and the non-contact power divider realizes non-contact mechanical movement through an air gap between the top metal and the unit metal columns.

2. The multi-beam antenna and beam scanning feed structure according to claim 1, characterized in that: The two pairs of feed units located at the same direction angle are sequentially synthesized into M-level input ports through M-level non-contact power dividers, and starting from the first M-level input port, the M-level input ports of two adjacent layers are synthesized into M-1-level input ports through M-1-level non-contact power dividers, and so on until they are synthesized into the first-level input port.

3. The multi-beam antenna and beam scanning feed structure according to any one of claims 1 or 2, characterized in that: The two feed source units in pairs located at the same direction angle are sequentially synthesized into sub-arrays through a waveguide power divider, and starting from the first synthesized sub-array, the sub-arrays of two adjacent layers are synthesized into input ports through the non-contact power divider.

4. The multi-beam antenna and beam scanning feed structure according to claim 1, characterized in that: The input end waveguide is connected to the gap waveguide section through a matching diaphragm, and the shape and size of the matching diaphragm are adjusted according to the working bandwidth requirements of the feed source unit.

5. The multi-beam antenna and beam scanning feed structure according to claim 1, characterized in that: The cylindrical Luneburg lens has a total of N layers, the inner N-2 layers adopt a dielectric ring unit structure, and the outermost two layers adopt a discrete dielectric column unit structure. The outermost two discrete dielectric ring unit structures are connected as a whole through dielectric rings, and then the ten-layer structure is connected through radial dielectric rods to form an overall lens structure.

6. The multi-beam antenna and beam scanning feed structure according to claim 1, characterized in that: The input ends of the plurality of feed units formed by rotation on the azimuth plane are converted to input ends located on the same plane through the curved waveguide.

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