A slow wave line co-planar frequency scanning antenna array

Abstract

This invention relates to a slow-waveline coplanar frequency-scanning antenna array, belonging to the field of frequency-scanning antenna technology, and solves the problem of large space occupation caused by the independent design of slow-wavelines and radiating elements in existing frequency-scanning antennas. The slow-waveline coplanar frequency-scanning antenna array of this invention includes multiple linear arrays of coplanar frequency-scanning elements; each coplanar frequency-scanning element includes multiple consecutive radiating elements; each radiating element includes a rectangular waveguide, a radiating slot, a tuning platform, and a radiating cavity. An "Ω"-shaped slow-waveline is arranged between the multiple radiating elements. This invention achieves miniaturization and low profile of the frequency-scanning antenna by setting an "Ω"-shaped slow-waveline with coplanar waveguides.

Description

Technical Field

[0001] This invention relates to the field of frequency-scanning antenna technology, and more particularly to a slow-waveline coplanar frequency-scanning antenna array. Background Technology

[0002] A frequency-scanning antenna, or simply FLSA antenna, has a beam pointing that changes with the transmitter's frequency; therefore, the beam pointing is a function of frequency. In a frequency-scanning radar, each frequency antenna forms a beam in space, and the frequency of the received echo signal guides the target's direction.

[0003] Frequency-scanning antennas can be implemented using two methods: waveguides and microstrip lines. Microstrip lines suffer from higher transmission losses, making it difficult to achieve high-efficiency radiation. Waveguides, on the other hand, due to their enclosed transmission characteristics, often achieve higher radiation efficiency under good matching conditions. A frequency-scanning antenna consists of two parts: a general radiating array and slow-wave lines.

[0004] Slow-wave lines are the feeding system for frequency-scanning antennas. They provide electromagnetic waves with suitable amplitude and phase requirements to the antenna array. When the frequency changes, they cause the equiphase surface of the line source to shift, thereby changing the beam direction and realizing beam spatial scanning.

[0005] There are many basic structural forms of slow wave lines. They mainly include: 1) serpentine lines, which can be made using coaxial lines or rectangular waveguides. Coaxial serpentine lines are mainly used for lower frequencies, while rectangular waveguide slow wave lines are used for higher frequencies; 2) helical lines, which are often made of rectangular waveguides; 3) rectangular waveguides filled with a high dielectric constant medium; 4) folded waveguides, etc.

[0006] Frequency-scanning slow-wave lines used in radar systems must be able to withstand high power and have low loss. Currently, the most widely used type is the serpentine rectangular waveguide slow-wave line.

[0007] Slow-wave lines are generally designed independently, occupying a large space, and are configured in a T-shape or L-shape with the radiating array, or are connected by a 90° bend waveguide to make the slow-wave lines parallel and coplanar with the radiating array. Although this can achieve a low profile, the entire aperture also needs to be enlarged, occupying a large space. Summary of the Invention

[0008] Based on the above analysis, the present invention aims to provide a slow-wave line coplanar frequency-scanning antenna array to solve the problem that the slow-wave line and radiating element of existing frequency-scanning antennas occupy a large space due to their independent design.

[0009] The objective of this invention is mainly achieved through the following technical solutions:

[0010] A slow-waveline coplanar frequency-scanning antenna array, the slow-waveline coplanar frequency-scanning antenna array comprising multiple linear array coplanar frequency-scanning elements;

[0011] The coplanar frequency scanning unit includes multiple consecutive radiating units; an "Ω"-shaped slow wave line is arranged between the multiple radiating units.

[0012] Furthermore, the radiating unit includes: a rectangular waveguide, a radiating slot, a tuning platform, and a radiating cavity.

[0013] Furthermore, the radiation slot is a rectangular slot disposed on a rectangular waveguide.

[0014] Furthermore, radiation cavities are provided at both ends of the radiation slit.

[0015] Furthermore, tuning platforms are provided on both sides of the radiation slit.

[0016] Furthermore, the tuning platform is a rectangular metal solid.

[0017] Furthermore, the radiation cavity is an annular metal shell.

[0018] Furthermore, the slow wave line is integrally formed with the rectangular waveguide and protrudes from the upper surface of the rectangular waveguide.

[0019] Furthermore, the plurality of radiation slots are equally spaced on the rectangular waveguide of the coplanar frequency scanning unit.

[0020] Furthermore, the depth to which the tuning stage penetrates the rectangular waveguide is greater than the depth to which the radiation slot cuts into the rectangular waveguide.

[0021] This invention belongs to the field of frequency-scanning antenna technology, specifically relating to a method for implementing a frequency-scanning antenna. By forming a linear array of coplanar frequency-scanning units composed of multiple radiating elements, a slow-waveline coplanar frequency-scanning antenna array can be constructed, thereby achieving miniaturization, low profile, and low cost of the frequency-scanning antenna.

[0022] The technical solution of this invention can achieve at least one of the following effects:

[0023] 1. Miniaturization.

[0024] The slow-wave line coplanar frequency-scanning antenna array of the present invention processes the slow-wave line 4 into an Ω-shaped curved shape, thereby maximizing the length of the slow-wave line 4 while keeping the spacing of the radiating elements 11 unchanged. With the same slow-wave line length, the slow-wave line coplanar frequency-scanning antenna array of the present invention, by employing an Ω-shaped curved slow-wave line, minimizes the length of the frequency-scanning antenna, achieving miniaturization of the frequency-scanning antenna array.

[0025] 2. Low profile.

[0026] In conventional frequency-scanning antennas, the array surface and slow-wave lines are independent of each other and are arranged in a T-shape or L-shape, resulting in a relatively high profile. In this invention, the slow-wave lines are arranged coplanarly with the linear array, achieving miniaturization and a low profile for the frequency-scanning antenna.

[0027] 3. Low cost.

[0028] This invention integrates the design and fabrication of the radiating array and slow-wave lines, reducing machining and welding time and material costs by approximately half. Furthermore, the antenna array can employ a combination of frequency and phase scanning to achieve one-dimensional frequency and phase scanning functions, reducing the number of TR components by half and facilitating low-cost array design.

[0029] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0030] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0031] Figure 1 This is a structural diagram of the slow-waveline coplanar frequency-scanning linear array of Embodiment 1 of the present invention;

[0032] Figure 2 This is a top view of the slow-waveline coplanar frequency-scanning linear array of Embodiment 1 of the present invention;

[0033] Figure 3 This is a schematic diagram of the coplanar frequency scanning unit of the slow-waveline coplanar frequency scanning array according to Embodiment 1 of the present invention;

[0034] Figure 4 for Figure 3 A magnified view of a local radiating element in the image;

[0035] Figure 5 This is a schematic diagram of the structure of a slow wave line;

[0036] Figure 6 This is the frequency sweep pattern of the slow-waveline coplanar frequency-sweeping linear array of the present invention;

[0037] Figure 7 The slow-waveline coplanar frequency-scanning linear array phase scanning pattern provided in the embodiments of the present invention.

[0038] Figure label:

[0039] 1-Coplanar frequency scanning unit; 11-Radiation unit; 2-Radiation slot; 3-Tuning stage; 4-Slow wave line; 41-First straight section; 42-Second straight section; 43-Arc-shaped section; 44-U-shaped section; 5-Radiation cavity. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0041] Example 1

[0042] A specific embodiment of the present invention discloses a slow-waveline coplanar frequency-scanning antenna array, such as... Figure 1 , Figure 2 As shown, it includes multiple coplanar frequency scanning units 1, which are linearly arranged. Each coplanar frequency scanning unit 1 includes multiple consecutive radiation units 11. Each radiation unit includes a rectangular waveguide, a radiation slot 2, a tuning platform 3, a slow wave line 4, and a radiation cavity 5.

[0043] Specifically, a plurality of equally spaced radiating slots 2 are provided on the rectangular waveguide. Radiation cavities 5 are provided at both ends of the radiating slots 2, and tuning platforms 3 are provided on both sides of the radiating slots 2; the slow wave lines 4 are coplanar with the rectangular waveguide, and the slow wave lines 4 between adjacent radiating slots 2 are Ω-shaped.

[0044] The slow-wave line coplanar frequency-scanning antenna array of the present invention radiates electromagnetic energy through a radiation slot 2 opened on the narrow side of a rectangular waveguide. The slow-wave line 4 is arranged in the radiation slot 2, and radiation cavities 5 are opened at both ends of the radiation slot 2 to meet the radiation conditions of the narrow side slot of the waveguide and realize the normal radiation of electromagnetic waves. Thus, the coplanar design of the radiation array surface and the slow-wave line of the frequency-scanning antenna is realized.

[0045] Furthermore, the slow-waveline coplanar frequency-scanning antenna array of the present invention is composed of multiple coplanar frequency-scanning units 1, and the multiple coplanar frequency-scanning units 1 are arranged at equal intervals.

[0046] Furthermore, in this invention, a rectangular waveguide made of metal is used as the main structure of the radiating unit 11, such as... Figure 1 As shown.

[0047] In this invention, the radiation unit 11 includes: a radiation slit 2, a tuning platform 3, and a radiation cavity 5. The structure of each part is described below:

[0048] Structure of Radial Slit 2:

[0049] The radiation slot 2 is a rectangular slot formed on a rectangular waveguide; multiple radiation slots 2 of the same size are formed on the rectangular waveguide, and the multiple radiation slots 2 are distributed at equal intervals on the rectangular waveguide.

[0050] The relationship between the length and width of the radiation slot 2 and the working wavelength is as follows: the longer the working wavelength, the larger the length and width of the radiation slot 2 and the deeper the radiation slot 2 cuts into the waveguide.

[0051] The structure of tuning station 3 is as follows:

[0052] In one specific embodiment of the present invention, the tuning stage 3 is a rectangular metal solid.

[0053] Furthermore, the depth to which the tuning stage 3 penetrates the rectangular waveguide is greater than the depth to which the radiation slit 2 cuts into the rectangular waveguide.

[0054] Furthermore, the correspondence between the length and width of the tuning stage 3 and the operating wavelength of the slow-waveline coplanar frequency-scanning antenna array is as follows: the longer the operating wavelength, the greater the length and width of the tuning stage 3, and the deeper it penetrates into the waveguide.

[0055] Furthermore, the narrow side of the rectangular waveguide is narrowed, and the size of the tuning stage 3 is adjusted through simulation calculations to meet the electromagnetic wave energy amplitude weighting requirements.

[0056] The structure of radiation cavity 5 is as follows:

[0057] In one specific embodiment of the present invention, such as Figure 4 As shown, radiation cavities 5 are provided at both ends of the radiation gap 2; the radiation cavity 5 is an annular metal shell used to realize the radiation of electromagnetic waves.

[0058] The structure of slow wave line 4 is as follows:

[0059] In this invention, the slow-wave line 4 and the radiating body are an integral structure; the slow-wave line 4 is a curved structure with continuous Ω-shaped bends, such as... Figure 2 As shown.

[0060] Furthermore, the slow-wave line 4 between adjacent radiation slits 2 has an "Ω"-shaped bend, as shown... Figure 3 As shown.

[0061] In one specific embodiment of the present invention, the slow-wave line 4 and the rectangular waveguide are the same component; the slow-wave line 4 is disposed above the radiating body and protrudes from the upper surface of the radiating body, such as... Figure 3 As shown.

[0062] In one specific embodiment of the present invention, the slow wave line 4 is integrally formed with the rectangular waveguide; and the slow wave line 4 has multiple "Ω"-shaped bends, such as... Figure 3 As shown

[0063] Furthermore, a radiating element 11 is provided on the slow-wave line 4 at every interval of an "Ω"-shaped bend, such as... Figure 3 As shown.

[0064] Furthermore, the length of the cross-section of slow wave line 4 is 6.5 mm, as shown below. Figure 1 As shown.

[0065] Furthermore, the width of the cross-section of the slow wave line 4 is 1 mm, such as... Figure 1 As shown.

[0066] Furthermore, the "Ω"-shaped bend of slow wave line 4 has a symmetrical structure, such as... Figure 4 , Figure 5 As shown.

[0067] In one specific embodiment of the present invention, the "Ω"-shaped bend includes: a first straight portion 41, two second straight portions 42, four arc-shaped portions 43, and two U-shaped portions 44, as shown below. Figure 5 As shown. While maintaining the same spacing between radiating elements 11, the length of the slow-wave line 4 is maximized. With the same slow-wave line length, the slow-wave line coplanar frequency-scanning antenna array of the present invention minimizes the length of the frequency-scanning antenna by employing an "Ω"-shaped bending design for the slow-wave line, thus achieving miniaturization of the frequency-scanning antenna array.

[0068] In one specific embodiment of the present invention, the two second straight portions 42 are symmetrically arranged, such as... Figure 5 As shown.

[0069] In one specific embodiment of the present invention, such as Figure 5 As shown, the two U-shaped portions 44 are symmetrically arranged, as... Figure 5 As shown.

[0070] Furthermore, the first straight portion 41 and the U-shaped portion 44 are arranged vertically parallel; and the second straight portion 42 is perpendicular to the U-shaped portion 44, as shown below. Figure 5 As shown.

[0071] In one specific embodiment of the present invention, such as Figure 5 As shown, the two ends of the first straight section 41 are connected to the two second straight sections 42 through the arc-shaped section 43.

[0072] In one specific embodiment of the present invention, the second straight portion 42 and the U-shaped portion 44 are connected by the arc-shaped portion 43, such as... Figure 5 As shown.

[0073] It is worth noting that the above-mentioned first straight section 41, two second straight sections 42, four arc-shaped sections 43 and two U-shaped sections 44 are all divisions made to facilitate the description of the shape and structure of the slow wave line 4, and are not independent parts.

[0074] In other words, the first straight section 41, the two second straight sections 42, the four arc-shaped sections 43 and the two U-shaped sections 44 are integrated into one structure, forming an "Ω" shaped bend in the waveguide coplanar slow wave line of the present invention, and multiple "Ω" shaped bends form the waveguide coplanar slow wave line of the present invention.

[0075] In one specific embodiment of the present invention, the slow-wave line 4 includes nine "Ω"-shaped bends, and radiating elements 11 are provided at both ends of the "Ω"-shaped bends, such as... Figure 1-3 As shown.

[0076] During implementation:

[0077] like Figure 1 , Figure 2 As shown, the slow-wave line coplanar frequency-scanning antenna array of the present invention consists of a radiation slot 2, a slow-wave line 4, and a radiation cavity 5. By narrowing the narrow side of the rectangular waveguide, the size of the tuning stage 3 is changed through simulation calculation, and the admittance value of the radiation slot 2 is adjusted to achieve the best radiation efficiency of the antenna in the spatial domain of the set direction.

[0078] Electromagnetic waves are fed in through the port of the slow-wave line coplanar frequency-sweeping linear array. The tuning stage 3 and the radiation gap 2 are alternately configured to cooperate with the slow-wave line 4 so that the electromagnetic waves meet the phase difference required by the design at the radiation gap 2, thereby radiating electromagnetic waves into space in a set direction.

[0079] The slow-waveline coplanar frequency-scanning linear array of the present invention can adjust the beam direction of the frequency-scanning dimensional pattern by changing the operating frequency of the incident electromagnetic wave.

[0080] Example 2

[0081] This embodiment provides a specific structure of the slow-waveline coplanar frequency-sweeping antenna array described in Embodiment 1:

[0082] Specifically, such as Figure 1 As shown, the slow-wave line coplanar frequency-scanning antenna array of this embodiment is composed of 8 groups of coplanar frequency-scanning units 1 arranged linearly; the spacing between adjacent coplanar frequency-scanning units 1 is 6mm, and multiple coplanar frequency-scanning units 1 are arranged at equal intervals.

[0083] In one specific embodiment of the present invention, the rectangular waveguide is a metal part with a length of 6.5 mm and a width of 1 mm.

[0084] Specifically, in one embodiment of the present invention, the radiating slot 2 is a rectangular vertical slot; the radiating slot 2 passes through the slow wave line 4 and cuts into the rectangular waveguide, such as... Figure 1 As shown.

[0085] In one specific embodiment of the present invention, the length of the radiating slot 2 is 1.7 mm, the width of the radiating slot 2 is 0.6 mm, and the depth of the radiating slot 2 cutting into the rectangular waveguide is 2.2 mm.

[0086] Specifically, the tuning stage 3 is a rectangular metal object with a length of 0.4 mm and a width of 0.4 mm.

[0087] In one specific embodiment of the present invention, the tuning stage 3 penetrates the rectangular waveguide to a depth greater than the depth to which the radiation slit 2 penetrates the rectangular waveguide by 0.5 mm; or, the height difference between the tuning stage 3 and the radiation slit 2 is 0.5 mm.

[0088] Specifically, the length of the cross-section of the slow wave line 4 is 6.5 mm, and the width of the cross-section of the slow wave line 4 is 1 mm.

[0089] Specifically, in one embodiment of the present invention, the radiation cavity 5 is a metal shell with a length of 2.47 mm, a width of 0.57 mm, and a depth of 7.125 mm.

[0090] In the Ka band, the slow-wave linear coplanar frequency-scanning linear array provided in this embodiment can achieve a frequency sweep of -21° to 12° within a 4GHz bandwidth, such as... Figure 6 As shown.

[0091] In the Ka band, the slow-wave linear coplanar frequency-scanning linear array provided in this embodiment can achieve ±15° grating-lobe-free scanning at its center frequency in the phase-scanning dimension, such as... Figure 7 As shown.

[0092] In the remaining bands of the Ka band, the dimensions of the radiation slot 2, the tuning platform 3, and the radiation cavity 5 are adjusted accordingly based on the wavelength ratio between the band in which the antenna array is located and the Ka band.

[0093] Compared with the prior art, the slow-waveline coplanar frequency-scanning antenna array provided by the present invention has at least one of the following beneficial effects:

[0094] 1. Low profile.

[0095] In conventional frequency-scanning antenna arrays, the slow-wave lines are independent of each other and are arranged in a T-shape or L-shape, resulting in a relatively high profile. The slow-wave line coplanar frequency-scanning antenna array of this invention achieves miniaturization and a low profile by arranging the slow-wave lines 4 coplanarly with the rectangular waveguide of the antenna array, thus reducing the antenna's footprint.

[0096] 2. Low cost.

[0097] This invention integrates the rectangular waveguide of the radiating element with the slow-wave line 4, combining the slow-wave line 4 and the rectangular waveguide onto a single metal component through machining. This reduces welding time and material costs. Furthermore, the antenna array can achieve one-dimensional frequency scanning and one-dimensional phase scanning using a combination of frequency and phase scanning, halving the number of TR components and facilitating low-cost array design.

[0098] 3. Miniaturization

[0099] The slow-wave line coplanar frequency-scanning antenna array of the present invention processes the slow-wave line 4 into an Ω-shaped curved shape, thereby maximizing the length of the slow-wave line 4 while keeping the spacing of the radiating elements 11 unchanged.

[0100] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A slow-waveline coplanar frequency-scanning antenna array, characterized in that, The slow-waveline coplanar frequency-scanning antenna array includes multiple linear array coplanar frequency-scanning elements (1); The coplanar frequency scanning unit (1) includes multiple consecutive radiating units (11); an "Ω"-shaped slow wave line (4) is arranged between the multiple radiating units (11); the slow wave line (4) is integrally formed with the rectangular waveguide and protrudes from the upper surface of the rectangular waveguide; the slow wave line (4) has multiple "Ω"-shaped bends; a radiating unit (11) is arranged on the slow wave line (4) at every "Ω"-shaped bend; the "Ω"-shaped bend includes: a first straight section (41), two second straight sections (42), four arc-shaped sections (43) and two U-shaped sections (44), the two second straight sections (42) are symmetrically and spaced apart, the two U-shaped sections (44) are symmetrically and spaced apart, the first straight section (41) and the U-shaped section (44) are arranged in a symmetrical manner. 4) The upper and lower parts are arranged in parallel. The second straight part (42) is perpendicular to the U-shaped part (44). The two ends of the first straight part (41) are connected to the two second straight parts (42) through the arc part (43). The second straight part (42) and the U-shaped part (44) are connected through the arc part (43). The radiation unit (11) includes: a rectangular waveguide, a radiation slot (2), a tuning platform (3) and a radiation cavity (5). The radiation slot (2) is a rectangular slot set on the rectangular waveguide. The two ends of the radiation slot (2) are provided with radiation cavities (5). The two sides of the radiation slot (2) are provided with tuning platforms (3). The tuning platform (3) is a rectangular metal entity. The radiation cavity (5) is an annular metal shell.

2. The slow-waveline coplanar frequency-scanning antenna array according to claim 1, characterized in that, Multiple radiation slots (2) are equally spaced on the rectangular waveguide of the coplanar frequency scanning unit (1).

3. The slow-waveline coplanar frequency-scanning antenna array according to claim 2, characterized in that, The depth into the rectangular waveguide by the tuning stage (3) is greater than the depth into the rectangular waveguide by the radiation slit (2).

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