A waveguide coplanar slow wave line

Abstract

The application relates to a waveguide coplanar slow wave line, belonging to the technical field of frequency scanning antennas, and solves the problem of large space occupation caused by independent design of the slow wave line and the radiation unit of the frequency scanning antenna in the prior art. The waveguide coplanar slow wave line is integrated with a rectangular waveguide; the slow wave line has multiple omega-shaped bends. One radiation unit is arranged on the slow wave line every interval of the omega-shaped bends. The application realizes the longest length of the slow wave line under the premise of fixed spacing of the radiation units, and realizes low profile design by arranging the slow wave line and the waveguide to be coplanar.

Description

Technical Field

[0001] This invention relates to the field of frequency-scanning antenna technology, and more particularly to a slow-wave line with waveguide coplanarity. 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, providing electromagnetic waves with suitable amplitude and phase requirements to the antenna array. When the frequency changes, the equiphase surface of the line source shifts, thereby altering the beam direction and achieving spatial beam scanning. Slow-wave lines have various basic structural forms, mainly including: 1) serpentine lines, which can be made using coaxial lines or rectangular waveguides. Coaxial serpentine lines are mainly used at lower frequencies, while rectangular waveguide slow-wave lines are used at higher frequencies; 2) helical lines, often constructed from rectangular waveguides; 3) rectangular waveguides filled with a high-dielectric-constant dielectric; 4) pleated waveguides, etc.

[0005] Frequency-scanning slow-wave lines used in radar systems must be able to withstand high power and have low loss. Currently, the most commonly used slow-wave lines are serpentine rectangular waveguides. 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 connected by a 90° bend waveguide to make the slow-wave line parallel and coplanar with the radiating array. Although this can achieve a low profile, the overall aperture also needs to be increased, occupying a large space. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a waveguide-coplanar slow wave line to solve the problem of large space occupation caused by the independent design of the slow wave line and radiating element in existing frequency-scanning antennas.

[0007] The objective of this invention is mainly achieved through the following technical solutions:

[0008] A slow waveline coplanar with a waveguide, the slow waveline being integrally formed with a rectangular waveguide; the slow waveline having multiple "Ω" shaped bends.

[0009] Furthermore, a radiating element is provided at every interval of an "Ω" shaped bend on the slow wave line.

[0010] Furthermore, the length of the cross-section of the slow wave line is 6.5 mm.

[0011] Furthermore, the width of the cross-section of the slow wave line is 1 mm.

[0012] Furthermore, the "Ω" shape is bent into a symmetrical structure.

[0013] Furthermore, the "Ω" shaped bend includes: a first straight section, two second straight sections, four arc-shaped sections, and two U-shaped sections.

[0014] Furthermore, the two second straight sections are arranged symmetrically.

[0015] Furthermore, the two U-shaped portions are arranged symmetrically.

[0016] Furthermore, the two ends of the first straight section are connected to the two second straight sections through the arc-shaped section.

[0017] Furthermore, the second straight portion and the U-shaped portion are connected by the arc-shaped portion.

[0018] The technical solution of this invention can achieve at least one of the following effects:

[0019] 1. This invention belongs to the field of frequency-scanning antenna technology, specifically relating to a slow-wave line with a coplanar waveguide. In this invention, the slow-wave line and the waveguide are arranged coplanarly, meaning the slow-wave line and the waveguide are an integral structure. In conventional frequency-scanning antennas, the array surface and the slow-wave line 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 line and the linear array are arranged coplanarly, achieving miniaturization and a low profile for the frequency-scanning antenna.

[0020] 2. 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 utilize 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.

[0021] 3. By setting an "Ω"-shaped bend in the slow-wave line, the present invention processes the slow-wave line into an Ω-shaped curved shape. Under the premise that the spacing of the radiating elements remains unchanged, the length of the slow-wave line is extended to the maximum extent, which improves the integration of the frequency-scanning antenna and is more conducive to the miniaturization of the frequency-scanning antenna array.

[0022] 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

[0023] 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.

[0024] Figure 1 This is a structural diagram of the slow-waveline coplanar frequency-scanning linear array of Embodiment 1 of the present invention;

[0025] Figure 2 This is a top view of the slow-waveline coplanar frequency-scanning linear array of Embodiment 1 of the present invention;

[0026] 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;

[0027] Figure 4 for Figure 3 A magnified view of a local radiating element in the image;

[0028] Figure 5 This is a schematic diagram of the slow wave line structure;

[0029] Figure 6 This is the frequency sweep pattern of the slow-waveline coplanar frequency-sweeping linear array of the present invention;

[0030] Figure 7 The slow-waveline coplanar frequency-scanning linear array phase scanning pattern provided in the embodiments of the present invention.

[0031] Figure label:

[0032] 1-Coplanar frequency scanning unit; 11-Radiation unit; 2-Radiation slot; 3-Tuning stage; 4-Slow wave line; 5-Radiation cavity;

[0033] 41-First straight section; 42-Second straight section; 43-Curved section; 44-U-shaped section. Detailed Implementation

[0034] 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.

[0035] Example 1

[0036] A specific embodiment of the present invention discloses a slow waveline with waveguide coplanarity, characterized in that the slow waveline 4 is integrally formed with a rectangular waveguide; the slow waveline 4 has multiple "Ω"-shaped bends, such as... Figure 3 As shown.

[0037] In one specific embodiment of the present invention, 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.

[0038] In one specific embodiment of the present invention, the length of the cross-section of the slow wave line 4 is 6.5 mm, such as... Figure 1 As shown.

[0039] In one specific embodiment of the present invention, the width of the cross-section of the slow wave line 4 is 1 mm, such as... Figure 1 As shown.

[0040] In one specific embodiment of the present invention, the "Ω" shaped bend is a symmetrical structure, such as... Figure 4 As shown.

[0041] 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.

[0042] In one specific embodiment of the present invention, the two second straight portions 42 are symmetrically arranged, such as... Figure 5 As shown.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In one specific embodiment of the present invention, the slow wave line 4 includes nine “Ω” shaped bends, and radiation units 11 are provided at both ends of the “Ω” shaped bends.

[0049] Example 2

[0050] A specific embodiment of the present invention provides a slow-waveline coplanar frequency-scanning antenna array based on the waveguide coplanar slow-waveline of Embodiment 1.

[0051] The slow-waveline coplanar frequency-scanning antenna array includes: multiple coplanar frequency-scanning elements 1, which are linearly arranged. Each coplanar frequency-scanning element 1 includes: multiple consecutive radiating elements 11. Each radiating element includes: a rectangular waveguide, a radiating slot 2, a tuning platform 3, a slow-waveline 4, and a radiating cavity 5.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] Furthermore, the relationship between the length and width of the radiation slot 2 and the operating wavelength of the frequency-scanned antenna array is as follows: the longer the operating wavelength, the larger the length and width of the radiation slot 2 and the deeper the radiation slot 2 cuts into the waveguide.

[0058] Furthermore, 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.

[0059] Furthermore, the slow-wave line 4 between adjacent radiation slits 2 has an "Ω"-shaped bend, as shown below. Figure 3 As shown.

[0060] 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.

[0061] In one specific embodiment of the present invention, the tuning stage 3 is a rectangular metal solid.

[0062] Furthermore, the depth to which the tuning stage 3 penetrates the rectangular waveguide is greater than the depth to which the radiation slot 2 cuts into the rectangular waveguide.

[0063] Furthermore, the relationship between the length and width of the tuning stage 3 and the operating wavelength of the 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.

[0064] 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.

[0065] In one specific embodiment of the present invention, 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.

[0066] Furthermore, the specific structure of the "Ω"-shaped bend in the slow wave line 4 includes: a first straight section 41, two second straight sections 42, four arc-shaped sections 43, and two U-shaped sections 44, as shown below. Figure 6 As shown.

[0067] Specifically, the "Ω" shaped bend is a symmetrical structure, with two second straight sections 42 symmetrically arranged and two U-shaped sections 44 also symmetrically arranged.

[0068] Specifically, the two ends of the first straight section 41, which is bent in an Ω shape, are connected to the second straight section 42 via an arc-shaped section 43, and the second straight section 42 is connected to the U-shaped section 44 via the arc-shaped section 43, as shown. Figure 5 As shown.

[0069] During implementation:

[0070] like Figures 1-3 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.

[0071] Electromagnetic waves are fed in through the port of the slow-wave line coplanar frequency-scanning linear array. The tuning stage 3 and the radiation gap 2 are alternately configured to cooperate with the slow-wave line 4 to perform electromagnetic radiation. By setting the shape of the slow-wave line 4 and the length of the Ω-shaped bend, the electromagnetic waves at the radiation gap 2 meet the phase difference required by the design, thereby radiating electromagnetic waves into space in a set direction.

[0072] 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.

[0073] Example 3

[0074] In one specific embodiment of the slow-waveline coplanar frequency-scanning linear array of the present invention, such as... Figure 1 As shown, the slow-wave line coplanar frequency-scanning antenna array is composed of 8 groups of coplanar frequency-scanning elements 1 arranged linearly; the spacing between adjacent coplanar frequency-scanning elements 1 is 6mm, and multiple coplanar frequency-scanning elements 1 are arranged at equal intervals.

[0075] 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.

[0076] Furthermore, the slow wave line 4 is coplanar with the rectangular waveguide and is an integral structure.

[0077] In one specific embodiment of the present invention, the radiating slot 2 is a rectangular vertical slot that passes through the slow wave line 4 and cuts into the rectangular waveguide, as shown below. Figure 1 As shown.

[0078] 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 to which the radiating slot 2 cuts into the rectangular waveguide is 2.2 mm.

[0079] In one specific embodiment of the present invention, the tuning platform 3 is a rectangular metal entity with a length of 0.4 mm and a width of 0.4 mm. The depth to which the tuning platform 3 penetrates the rectangular waveguide is 0.5 mm greater than the depth to which the radiation slit 2 penetrates the rectangular waveguide; or, in other words, the height difference between the tuning platform 3 and the radiation slit 2 is 0.5 mm.

[0080] In one specific embodiment of the present invention, 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.

[0081] In one specific 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] Compared with the prior art, the waveguide coplanar slow wave line and the slow wave line coplanar frequency-scanning antenna array provided by the present invention have at least one of the following beneficial effects:

[0086] 1. Low profile.

[0087] 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.

[0088] 2. Low cost.

[0089] 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 employ a combination of frequency and phase scanning to achieve one-dimensional frequency and phase scanning functions, halving the number of TR components and facilitating low-cost array design.

[0090] 3. Miniaturization

[0091] 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.

[0092] 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 with waveguide coplanarity, characterized in that, The slow wave line (4) is integrated with the rectangular waveguide; the slow wave line (4) has multiple "Ω" shaped bends; A radiation unit (11) is provided on the slow wave line (4) at every "Ω" shaped bend; The "Ω" shaped bend creates a symmetrical structure. 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 arranged and spaced apart; the two U-shaped sections (44) are symmetrically arranged and spaced apart; the two ends of the first straight section (41) are connected to the two second straight sections (42) through the arc-shaped sections (43); the second straight sections (42) and the U-shaped sections (44) are connected through the arc-shaped sections (43); The radiation unit includes: a rectangular waveguide, a radiation slot (2), a tuning station (3), a slow wave line (4), and a radiation cavity (5); multiple equally spaced radiation slots (2) are provided on the rectangular waveguide; a radiation cavity (5) is provided at both ends of the radiation slot (2), and a tuning station (3) is provided on both sides of the radiation slot (2); the radiation slot (2) is a rectangular slot opened on the rectangular waveguide; the tuning station (3) is a cuboid metal solid; the radiation cavity (5) is an annular metal shell used to realize the radiation of electromagnetic waves.

2. The slow waveline with waveguide coplanarity according to claim 1, characterized in that, The length of the cross section of the slow wave line (4) is 6.5 mm.

3. The slow waveline with waveguide coplanarity according to claim 2, characterized in that, The width of the cross section of the slow wave line (4) is 1 mm.

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