Broadband dual-beam elliptical waveguide leaky-wave antenna

Abstract

The invention discloses a broadband dual-beam elliptical waveguide leaky-wave antenna, particularly relates to the technical field of communication, and solves the problems that most of elliptical waveguide leaky-wave antennas in the prior art can only support narrower frequency bands, the working capability of the elliptical waveguide leaky-wave antennas on a plurality of frequency bands is limited, and especially when the elliptical waveguide leaky-wave antennas need to be used in the plurality of frequency bands at the same time, the working efficiency of the elliptical waveguide leaky-wave antennas is low. And enough bandwidth and beam scanning capability are difficult to provide. According to the technical scheme, the elliptical waveguide adopts a four-transverse-groove unit design, and reasonable groove spacing is set; the antenna can work on 0-order and-1-order space harmonics at the same time, two radiation beams are generated, the beam scanning range is effectively expanded, and the radiation gain is improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a broadband dual-beam elliptical waveguide leaky-wave antenna. Background Art

[0002] Leaky wave antennas have been widely used in microwave and millimeter wave fields due to their simple feeding network and frequency beam scanning capability. Leaky wave antennas are an important component of modern wireless communication systems and are suitable for spectrum analyzers, automotive radar sensors, 5th generation mobile communications, and railway signal systems.

[0003] At present, leaky wave antennas based on printed circuit boards have the advantages of low cost, low profile and easy integration. However, due to the signal coverage requirements in special environments such as tunnels, leaky wave antennas based on printed circuit boards have large transmission losses and cannot meet the wireless communication needs in tunnels. In addition, although leaky coaxial cables are widely used, their operating frequency is limited, generally below 4 GHz, and the transmission loss of their conductors and dielectric materials increases with the increase of frequency.

[0004] Waveguide leaky wave antennas are suitable for high-frequency wireless communications above 4GHz due to their low high-frequency loss, and they exhibit superior performance in long-distance transmission. Elliptical waveguide leaky wave antennas have become an important choice among waveguide leaky wave antennas due to their stable transmission characteristics, low transmission loss, and ease of long-length manufacturing, transportation, and installation.

[0005] However, most existing elliptical waveguide leaky-wave antennas can only support narrower frequency bands and have limited operating capabilities in multiple frequency bands. Especially when they need to be used in multiple frequency bands at the same time (such as mobile 5G and WiFi5 / 6 / 6E / 7), existing technologies are difficult to provide sufficient bandwidth and beam scanning capabilities. Summary of the invention

[0006] Therefore, the present invention solves the technical problem that most of the elliptical waveguide leaky wave antennas in the prior art can only support narrower frequency bands and have limited working capabilities in multiple frequency bands, especially when they need to be used in multiple frequency bands (such as mobile 5G and WiFi 5 / 6 / 6E / 7) at the same time, it is difficult to provide sufficient bandwidth and beam scanning capabilities; the present invention provides a broadband dual-beam elliptical waveguide leaky wave antenna, which adopts a four-transverse slot unit design in the elliptical waveguide and a reasonable slot spacing. It can work on the 0th and -1st spatial harmonics at the same time, generate two radiation beams, effectively expand the beam scanning range and improve the radiation gain. In addition, through the broadband coaxial to elliptical waveguide transition structure design, it is possible to suppress high-order transmission modes, ensure single-mode operation, and ensure broadband operation of the antenna in the 4.5GHz to 8GHz frequency band. At the same time, by adopting a four-transverse slot structure of different widths, the suppression effect of high-order harmonics and open-stop bands can be better.

[0007] The present invention provides a broadband dual-beam elliptical waveguide leaky-wave antenna, comprising an elliptical waveguide tube and a plurality of four-transverse slot units. By reasonably designing the slot spacing, the antenna can simultaneously operate on the 0th and -1st spatial harmonics to generate two radiation beams, and effectively suppress high-order harmonics and open-stop bands to achieve broadband operation.

[0008] Furthermore, the four transverse slot units are arranged on the long axis of the elliptical waveguide and are symmetrical with respect to the short axis. The spacing between adjacent four transverse slot units is selected to be 75-85 mm to effectively control the frequency position of the high-order harmonic frequency and the open-stop band.

[0009] Furthermore, a through hole is provided in the long axis side wall of the elliptical waveguide tube, and the coaxial connector is provided on the through hole; the middle of the elliptical waveguide tube is provided as an elliptical waveguide leaky wave antenna part, and both ends are closed ends of the elliptical waveguide tube; one end of the short step impedance probe is connected to the inner conductor of the coaxial connector, and the other end passes through the through hole and extends into the elliptical waveguide tube.

[0010] Furthermore, the short step impedance probe includes two thick metal cylinders and two thin metal cylinders, the number of the thick metal cylinders and the number of the thin metal cylinders are the same; the thick metal cylinders and the thin metal cylinders are alternately connected in series to form an E-plane step impedance probe, which can effectively suppress high-order transmission modes and ensure the single-mode transmission bandwidth of the antenna. The distance between the coaxial connector and the four-transverse slot unit of the elliptical waveguide leaky wave antenna part is 10 to 50 mm.

[0011] Furthermore, the four-transverse groove unit includes a first transverse groove, a second transverse groove, a third transverse groove and a fourth transverse groove; the spacing between the third transverse groove and the first transverse groove is equal to the spacing between the fourth transverse groove and the second transverse groove.

[0012] Further, the spacing between the third transverse groove and the first transverse groove is (1+t1) / 4 of the spacing between the adjacent four transverse groove units; t1=0,1,2,...; 1+2k1<4. The spacing between the third transverse groove and the first transverse groove is (1+t2) / 6 of the spacing between the adjacent four transverse groove units; t2=0,1,2,...; 1+2k2<6; the spacing between the fourth transverse groove and the second transverse groove is (1+t2) / 6 of the spacing between the adjacent four transverse groove units.

[0013] Furthermore, the slot length of the four-transverse slot unit ranges from 44 to 50 mm, and the width ranges from 0.5 to 1.5 mm.

[0014] Furthermore, the slot widths of the four transverse slot units are inconsistent. The slot width of the second transverse slot is larger than the slot width of the first transverse slot by a (the range of a is 0.1 to 0.5 mm), the slot width of the third transverse slot is larger than the slot width of the first transverse slot by 1.5a*(1+t1) / (1+t2), and the slot width of the fourth transverse slot is larger than the slot width of the first transverse slot by 1.5a*(1+t1) / (1+t2)+a.

[0015] Furthermore, the four transverse grooves are symmetrical on the elliptical waveguide leaky-wave antenna, and the first transverse groove, the second transverse groove, the third transverse groove, and the fourth transverse groove are successively away from the coaxial connector.

[0016] Furthermore, if the number of the four transverse groove units is an odd number, the groove widths of the four transverse groove units in the middle are consistent; if the number of the four transverse groove units is an even number, the groove widths of the two four transverse groove units in the middle are symmetrical in the middle.

[0017] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0018] 1. The broadband dual-beam elliptical waveguide leaky-wave antenna provided by the present invention adopts a four-transverse slot unit design. Through reasonable slot spacing, it can effectively suppress high-order harmonics and open-stop bands, and expand the working bandwidth of the elliptical waveguide leaky-wave antenna, thereby realizing broadband frequency band operation.

[0019] 2. The broadband dual-beam elliptical waveguide leaky-wave antenna provided by the present invention uses an E-plane stepped impedance probe design. The transition structure from the coaxial connector to the elliptical waveguide can effectively suppress high-order modes and ensure the broadband single-mode working bandwidth of the elliptical waveguide leaky-wave antenna.

[0020] 3. The broadband dual-beam elliptical waveguide leaky wave antenna provided by the present invention has a dual-beam radiation design, which enables the antenna to simultaneously generate two radiation beams on the 0th and -1st spatial harmonics, thereby expanding the beam scanning range. It is suitable for wireless communications in environments such as tunnels and solves the signal blind spot problem.

[0021] 4. The broadband dual-beam elliptical waveguide leaky-wave antenna provided by the present invention increases the radiation gain of the antenna, improves the overall performance of the antenna, and ensures good radiation characteristics within the frequency range by optimizing the multi-slot unit.

[0022] 5. The broadband dual-beam elliptical waveguide leaky-wave antenna provided by the present invention can achieve better suppression effects of high-order harmonics and open-stop bands by optimizing the multi-slot unit slots. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the local structure of the present invention;

[0026] Figure 3 It is a schematic diagram of the overall structure of the transition structure of the present invention;

[0027] Figure 4 is a schematic diagram of the leakage end of the elliptical waveguide of the present invention;

[0028] Figure 5 |S11| curve diagram of the present invention;

[0029] Figure 6 is a gain curve diagram of the present invention;

[0030] Description of reference numerals:

[0031] 1. Elliptical waveguide tube; 12. Closed end of elliptical waveguide tube; 13. Leakage section of elliptical waveguide tube; 2. Four-transverse slot unit; 21. First transverse slot; 22. Second transverse slot; 23. Third transverse slot; 24. Fourth transverse slot; 3. Coaxial connector; 31. Inner conductor; 4. Short step impedance probe; 41. Thick metal cylinder; 42. Thin metal cylinder; 5. Through hole. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] Embodiment 1:

[0034] This embodiment provides a broadband dual-beam elliptical waveguide leaky-wave antenna, such as Figure 1 and Figure 2 As shown, it includes: an elliptical waveguide 1, a four-transverse slot unit 2, and a coaxial connector 3.

[0035] like Figure 3As shown, in this embodiment, the transition includes an elliptical waveguide tube 1, a coaxial connector 3, and a short step impedance probe 4; a through hole 5 is provided in the long axis side wall of the elliptical waveguide tube 1, and the coaxial connector 2 is provided on the through hole; the middle of the elliptical waveguide tube 1 is provided as an elliptical waveguide tube leakage section 13, and the other end is an elliptical waveguide tube closed end 12, one end of the short step impedance probe 4 is connected to the inner conductor 31 of the coaxial connector 3, and the other end passes through the through hole 5 and extends into the elliptical waveguide tube 1.

[0036] The short step impedance probe 4 includes two thick metal cylinders 41 and two thin metal cylinders 42. The number of the thick metal cylinders 41 and the thin metal cylinders 42 is the same. The thick metal cylinders 41 and the thin metal cylinders 42 are alternately connected in series. The distance between the coaxial connector 3 and the four-transverse slot unit of the elliptical waveguide leakage end 13 is 10-50 mm.

[0037] The four-transverse groove unit 2 includes four transverse grooves, and the spacing between the third transverse groove 23 and the first transverse groove 21 is equal to the spacing between the fourth transverse groove 24 and the second transverse groove 22. The spacing between the second transverse groove 22 and the first transverse groove 21 is (1+t1) / 4 of the periodic spacing of the four-transverse groove unit; t1=0,1,2,·…·; 1+2k1<4. The spacing between the third transverse groove 23 and the first transverse groove 21 is (1+t2) / 6 of the periodic spacing of the four-transverse groove unit 2; t2=0,1,2,·…·; 1+2k2<6, and the spacing between the fourth transverse groove 24 and the second transverse groove 22 is (1+t2) / 6 of the periodic spacing of the four-transverse groove unit 2; the periodic spacing of the four-transverse groove unit 2 is the spacing between adjacent four-transverse groove units 2.

[0038] like Figure 4 As shown, the four transverse slot units 2 are arranged on the long axis of the elliptical waveguide 1 and are symmetrical relative to the short axis. The periodic spacing of the four transverse slot units 1 is selected to be 75 to 85 mm to effectively control the frequency position of the high-order harmonic frequency and the open-stop band. The slot length of the four transverse slot units 2 of the antenna ranges from 44 to 50 mm, and the slot width ranges from 0.5 to 1.5 mm.

[0039] Embodiment 2:

[0040] The inner dimensions of the elliptical waveguide tube 1 in this embodiment are: 49.2mm×21.6mm, the distance between the through hole 5 and the closed end 12 of the elliptical waveguide tube is 14.8mm, the radius of the through hole 5 is 2.05mm, the radii of the thick metal cylinder 41 and the thin metal cylinder 42 of the short step impedance probe 4 are 2.95mm and 0.7mm respectively, and the lengths of the thick metal cylinder 41 and the thin metal cylinder 42 are 2.7mm. The distance between the coaxial connector 3 and the four-transverse groove unit 2 of the leakage end 13 of the elliptical waveguide is 39.45mm. The spacing between the third transverse groove 23 and the first transverse groove 21 is equal to the spacing between the fourth transverse groove 24 and the second transverse groove 22. The spacing between the second transverse groove 22 and the first transverse groove 21 is 1 / 4 of the period spacing of the four-transverse groove unit. The spacing between the third transverse groove 23 and the first transverse groove 21 is 1 / 6 of the period spacing of the four-transverse groove unit 2, and the spacing between the fourth transverse groove 24 and the second transverse groove 22 is 1 / 6 of the period spacing of the four-transverse groove unit 2. The periodic spacing of the four-transverse slot unit 1 is selected to be 78 mm to effectively control the frequency position of the high-order harmonic frequency and the open-stop band. The slot hole of the four-transverse slot unit 2 of the antenna is 48 mm and the slot hole width is 1 mm.

[0041] like Figure 5 As shown in the figure, the S parameters of the elliptical waveguide leaky wave antenna under three different conditions (single slot unit, double slot unit, four slot unit) are compared. It can be seen that compared with the single slot, the multi-slot unit can greatly expand the bandwidth. The single slot unit has two open stop bands in the frequency band of 4.5 to 8 GHz. The double slot unit can suppress one open stop band. And the four slot unit can suppress two open stop bands at the same time.

[0042] like Figure 6 As shown in the figure, the gain parameters of the elliptical waveguide leaky wave antenna under three different conditions (single slot unit, double slot unit, and four slot unit) are compared. It can be seen that compared with the single slot, the multi-slot unit can greatly expand the dual-beam bandwidth. The single slot unit has four higher harmonics in the frequency band of 4.5 to 8 GHz. The double slot unit can suppress one higher harmonic. The four slot unit can suppress two higher harmonics at the same time. At the same time, it can be seen that the gain increases with the increase in the number of slots, and the gain of the four slots is significantly improved.

[0043] Embodiment 3:

[0044] This embodiment provides a broadband dual-beam elliptical waveguide leaky wave antenna when the widths of the four transverse slots are inconsistent. The inner dimensions of the elliptical waveguide tube 1 are: 49.2mm×21.6mm. The distance between the through hole 5 and the closed end 12 of the elliptical waveguide tube is 14.8mm. The radius of the through hole 5 is 2.05mm. The radii of the thick metal cylinder 41 and the thin metal cylinder 42 of the short step impedance probe 4 are 2.95mm and 0.7mm respectively. The lengths of the thick metal cylinder 41 and the thin metal cylinder 42 are 2.7mm. The distance between the coaxial connector 3 and the four transverse slot unit 2 of the elliptical waveguide leakage end 13 is 39.45mm. The spacing between the third transverse slot 23 and the first transverse slot 21 is equal to the spacing between the fourth transverse slot 24 and the second transverse slot 22. The spacing between the second transverse slot 22 and the first transverse slot 21 is 1 / 4 of the period spacing of the four transverse slot units. The spacing between the third transverse slot 23 and the first transverse slot 21 is 1 / 6 of the period spacing of the four transverse slot units 2, and the spacing between the fourth transverse slot 24 and the second transverse slot 22 is 1 / 6 of the period spacing of the four transverse slot units 2. The period spacing of the four transverse slot units 1 is selected to be 78mm to effectively control the frequency position of the high-order harmonic frequency and the open-stop band. The slot widths of the four transverse slot units 2 of the antenna are different, the first transverse slot width is 1mm, the second transverse slot width is 1.2mm, the third transverse slot width is 1.3mm, and the fourth transverse slot width is 1.5mm.

[0045] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A broadband dual-beam elliptical waveguide leaky-wave antenna, characterized in that: The invention comprises an elliptical waveguide tube (1), wherein a plurality of four-transverse slot units (2) are provided on the elliptical waveguide tube (1); the two ends of the elliptical waveguide tube (1) are elliptical waveguide tube closed ends (12), and the middle is an elliptical waveguide tube leakage section (13); and the elliptical waveguide tube (1) is provided with a coaxial connector (3).

2. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 1, characterized in that: The spacings between the plurality of four-transverse slot units (2) are equal, and the four-transverse slot units (2) are arranged on the long axis of the elliptical waveguide tube (1) and are symmetrical relative to the center of the short axis.

3. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 2, characterized in that: A through hole (5) is provided on the long axis side wall of the elliptical waveguide tube (1), and the coaxial connector (3) is arranged on the through hole (5); an inner conductor (31) is arranged in the coaxial connector (3), and the inner conductor (31) is connected to a short step impedance probe (4); an end of the short step impedance probe (4) away from the inner conductor (31) extends into the elliptical waveguide tube (1); the short step impedance probe (4) comprises two thick metal cylinders (41) and two thin metal cylinders (42); the thick metal cylinders (41) and the thin metal cylinders (42) are alternately connected in series.

4. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 3, characterized in that: The four-transverse groove unit (2) comprises a first transverse groove (21), a second transverse groove (22), a third transverse groove (23) and a fourth transverse groove (24); the spacing between the third transverse groove (23) and the first transverse groove (21) is equal to the spacing between the fourth transverse groove (24) and the second transverse groove (22).

5. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 4, characterized in that: The spacing between the third transverse groove (23) and the first transverse groove (21) is (1+t1) / 4 of the spacing between the adjacent four transverse groove units (2); t1=0, 1, 2,...; 1+2k1<4.

6. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 5, characterized in that: The spacing between the third transverse groove (23) and the first transverse groove (21) is (1+t2) / 6 of the spacing between the adjacent four transverse groove units (2); t2=0, 1, 2,...; 1+2k2<6; the spacing between the fourth transverse groove (24) and the second transverse groove (22) is (1+t2) / 6 of the spacing between the adjacent four transverse groove units (2).

7. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 6, characterized in that: The slot length of the four-transverse slot unit (2) ranges from 44 to 50 mm, and the width ranges from 0.5 to 1.5 mm; the distance between the coaxial connector (3) and the four-transverse slot unit (2) is 10 to 50 mm; and the spacing between adjacent four-transverse slot units (2) is 75 to 85 mm.

8. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 7, characterized in that: The slot widths of the four transverse slot units (2) are inconsistent. The slot width of the second transverse slot (22) is larger than the slot width of the first transverse slot (21) by a, and the range of a is 0.1 to 0.5 mm. The slot width of the third transverse slot (23) is larger than the slot width of the first transverse slot (21) by 1.5a*(1+t1) / (1+t2). The slot width of the fourth transverse slot (24) is larger than the slot width of the first transverse slot (21) by 1.5a*(1+t1) / (1+t2)+a.

9. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 8, characterized in that: The four transverse slot units (2) are symmetrical on the elliptical waveguide leaky wave antenna, and the first transverse slot (21), the second transverse slot (22), the third transverse slot (23), and the fourth transverse slot (24) are successively away from the coaxial connector (3).

10. The broadband dual-beam elliptical waveguide leaky-wave antenna according to claim 9, characterized in that: When the number of the four transverse slot units (2) is an odd number, the slot widths of the middle four transverse slot units (2) are consistent; when the number of the four transverse slot units (2) is an even number, the slot widths of the two middle four transverse slot units (2) are symmetrical relative to the middle of the elliptical waveguide tube (1).

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