45-degree polarized waveguide slot antenna

Abstract

The invention provides a 45-degree polarized waveguide slot antenna, and the antenna comprises a plurality of metal layers which are seamlessly attached, and the metal layers are a radiation layer, a slot layer, and a feed waveguide layer. The radiation layer is provided with a pair of C-shaped metal walls, and the bottom of the radiation layer is provided with a plurality of horn mouths. The slit layer is provided with a plurality of inclined slits which are arranged and distributed in parallel, the included angle between the longitudinal center line of each inclined slit and the longitudinal center line of the slit layer is 45 degrees, and the plurality of inclined slits correspond to the plurality of horn mouths one by one; the feed waveguide layer is provided with a ridge waveguide resonant cavity, the inner side of the cavity side wall is provided with a plurality of convex blocks, and the center of the bottom of the feed waveguide layer is provided with periodic concave-convex ridges; one end of the narrow side of the cavity side wall is provided with a rectangular feed waveguide port. Through the antenna with the multilayer metallization structure, the radiation performance of large broadband, high gain, low side lobe and low cross polarization is realized, and the antenna can be widely applied to communication systems such as millimeter wave satellites, radars and the like.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to a 45-degree polarized waveguide slot antenna. Background Art

[0002] At present, vehicle-mounted radar has become almost a necessary function for vehicles. Traditional millimeter-wave vehicle-mounted radar antennas mainly transmit vertically polarized and horizontally polarized signals, and most vehicle-mounted sensors at this stage also mainly transmit vertically polarized and horizontally polarized signals. Since they all use the same signal, the signals will interfere with each other.

[0003] In order to allow the millimeter-wave radar to avoid interference from other millimeter-wave radar sensors as much as possible, one method in the existing technical solutions is to eliminate the influence of interference signals through post-processing algorithms, and another method is to reduce the energy of the received interference signals from the perspective of the antenna. The 45-degree polarized antenna is such an antenna with anti-interference ability. At present, most 45-degree polarized antennas are mainly made of microstrip dielectric plates. This type of antenna cannot achieve large bandwidth, high gain, and high-efficiency radiation performance due to the loss of the dielectric. Summary of the invention

[0004] In response to the above problems, the present application provides a 45-degree polarized waveguide slot antenna, which solves the technical problem in the related art that the antenna is made of a microstrip dielectric plate and has losses, making it impossible to achieve large bandwidth, high gain, and high efficiency radiation performance.

[0005] The present application provides a 45-degree polarized waveguide slot antenna, the 45-degree polarized waveguide slot antenna comprising a plurality of seamlessly bonded metal layers, the metal layers being a radiation layer, a slot layer and a feeding waveguide layer; The radiation layer is provided with a pair of C-shaped metal walls, and a plurality of flared openings are provided at the bottom; The slot layer is provided with a plurality of oblique slots arranged parallel to each other, the angle between the longitudinal center line of the oblique slot and the longitudinal center line of the slot layer is 45 degrees, and the plurality of oblique slots correspond to the plurality of bell mouths one by one; The feed waveguide layer is provided with a ridge waveguide resonant cavity, the inner side of the cavity side wall is provided with a plurality of convex blocks, and the bottom center of the feed waveguide layer is provided with periodic concave-convex ridges; a rectangular feed waveguide opening is provided at one end of the narrow side of the cavity side wall.

[0006] Preferably, the shape of the horn mouth is a fan-shaped, pyramidal, conical or corrugated horn.

[0007] Preferably, the pair of C-shaped metal walls are arranged on both sides of the narrow side of the radiation layer and are symmetrical about the center of the radiation layer.

[0008] Preferably, the C-shaped metal wall comprises a bending structure that can be bent at any arc.

[0009] Preferably, the radiation layer and the slot layer are a metal layer, and the feeding waveguide layer is a metal layer.

[0010] Preferably, the oblique slit is a rectangle or an irregular trapezoid.

[0011] Preferably, the plurality of oblique slits are arranged along the longitudinal center line of the slot layer, and the distance between two adjacent oblique slits is in the range of [0.5λg,λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

[0012] Preferably, the plurality of protrusions are centrally symmetrically arranged with respect to the center of the ridge waveguide resonant cavity, and the distance between adjacent protrusions is [0.25λg, 0.75λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

[0013] Preferably, the shape of the protrusion is rectangular, triangular or trapezoidal.

[0014] Preferably, the shape of the concave-convex ridge is a periodic corrugated structure, and the corrugated structure can be a rectangular, triangular or sinusoidal corrugation.

[0015] The present application provides a 45-degree polarized waveguide slot antenna, which includes several seamlessly bonded metal layers, and the metal layers are respectively a radiation layer, a slot layer and a feeding waveguide layer; the radiation layer is provided with a pair of C-shaped metal walls, and a plurality of horn mouths are provided at the bottom; the slot layer is provided with a plurality of slanted slits arranged parallel to each other, and the angle between the longitudinal center line of the slanted slit and the longitudinal center line of the slot layer is 45 degrees, and the plurality of slanted slits correspond to the plurality of horn mouths one by one; the feeding waveguide layer is provided with a ridge waveguide resonant cavity, and a plurality of protrusions are provided on the inner side of the cavity side wall, and a periodic concave-convex ridge is provided at the bottom center of the feeding waveguide layer; a rectangular feeding waveguide mouth is provided at one end of the narrow side of the cavity side wall. The present application achieves the radiation performance of large bandwidth, high gain, low side lobe and low cross-polarization through the antenna of the multi-layer metallization structure, and can be widely used in communication systems such as millimeter wave satellites and radars. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0017] Figure 1A schematic diagram of the overall structure of a 45-degree polarized waveguide slot antenna provided in an embodiment of the present invention; Figure 2 is a schematic diagram of the overall structure of a 45-degree polarized waveguide slot antenna in another embodiment of the present invention; Figure 3 is a top view of the radiation layer 1 of the 45-degree polarization waveguide slot antenna in an embodiment of the present invention; Figure 4 is a top view of the slot layer 2 of the 45-degree polarized waveguide slot antenna in an embodiment of the present invention; Figure 5 is a top view of the feeding waveguide layer 3 of the 45-degree polarization waveguide slot antenna in an embodiment of the present invention; Figure 6 is a simulation curve diagram of |S11| of a 45-degree polarized waveguide slot antenna in an embodiment of the present invention; Figure 7 It is a simulation curve diagram of the 78.5GHz horizontal plane (Phi=0 degree) radiation pattern of the 45-degree polarization waveguide slot antenna in an embodiment of the present invention; Figure 8 It is a simulation curve diagram of the 78.5GHz horizontal plane (Phi=90 degrees) radiation pattern of the 45-degree polarization waveguide slot antenna in an embodiment of the present invention; Fig. 9 is a gain simulation curve diagram of a 45-degree polarized waveguide slot antenna in an embodiment of the present invention; The following are the descriptions of the reference numerals: 1-radiation layer, 1AA-first horn mouth, 1AB-second horn mouth, 1AC-third horn mouth, 1AD-fourth horn mouth, 1AE-fifth horn mouth, 1B- C-shaped metal wall, 2-slot layer, 2AA-first oblique slot, 2AB-second oblique slot, 2AC-third oblique slot, 2AD-fourth oblique slot, 2AE-fifth oblique slot, 3-feeding waveguide layer, 3A-ridge waveguide resonant cavity, 3AA-first bump, 3AB-second bump, 3AC-third bump, 3AD-fourth bump, 3AE-central ridge, 3AF-rectangular waveguide mouth. DETAILED DESCRIPTION

[0018] The following will describe the implementation methods of the present application in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present application applies technical means to solve technical problems and achieve corresponding technical effects can be fully understood and implemented accordingly. The embodiments of the present application and the various features in the embodiments can be combined with each other without conflict, and the technical solutions formed are all within the scope of protection of the present application.

[0019] As can be seen from the background technology, currently, most 45-degree polarized antennas are mainly made of microstrip dielectric plates. This type of antenna cannot achieve large bandwidth, high gain, and high efficiency radiation performance due to dielectric loss.

[0020] In view of this, the present application provides a 45-degree polarized waveguide slot antenna, which solves the technical problem in the related art that the antenna is made of a microstrip dielectric plate and has losses, and cannot achieve large bandwidth, high gain, and high efficiency radiation performance.

[0021] Embodiment 1:

[0022] Figure 1 A 45-degree polarized waveguide slot antenna is provided in an embodiment of the present application, such as Figure 1 As shown, the 45-degree polarized waveguide slot antenna includes a plurality of seamlessly bonded metal layers, wherein the metal layers are respectively a radiation layer, a slot layer and a feeding waveguide layer; Figure 1 From top to bottom are the radiation layer, slot layer and feeding waveguide layer.

[0023] It should be noted that the radiation layer, the slot layer and the feeding waveguide layer may be formed by metal CNC processing, or by plastic injection molding or CNC followed by surface metallization.

[0024] The radiation layer is provided with a pair of C-shaped metal walls, and a plurality of horn mouths are provided at the bottom.

[0025] It should be noted that the C-shaped metal wall can improve the radiation performance of the antenna and increase the gain of the antenna.

[0026] The slot layer is provided with a plurality of oblique slots which are arranged parallel to each other, the angle between the longitudinal center line of the oblique slot and the longitudinal center line of the slot layer is 45 degrees, and the plurality of oblique slots correspond to the plurality of bell mouths one by one.

[0027] It should be noted that the currents of the above-mentioned several slanted slit cut ridge waveguide resonant cavities couple the electromagnetic waves in phase to several bell mouths, and then radiate them into free space with high efficiency, radiating 45-degree polarized electromagnetic waves, with strong anti-interference ability, and are not affected by most existing sensors. In addition, the bell mouth structure can achieve high gain performance and realize the long-distance detection function of the radar.

[0028] The feed waveguide layer is provided with a ridge waveguide resonant cavity, the inner side of the cavity side wall is provided with a plurality of convex blocks, and the bottom center of the feed waveguide layer is provided with periodic concave-convex ridges; a rectangular feed waveguide opening is provided at one end of the narrow side of the cavity side wall.

[0029] It should be noted that the 45-degree polarized waveguide slot antenna disclosed in the present invention has a bandwidth covering 76-81 GHz and can be used in millimeter-wave vehicle-mounted radar antenna systems; a waveguide transmission line can be used for center feeding at the bottom or for feeding at the side, and a variety of feeding methods make the antenna flexible in array formation; Figure 1 It can be seen that the antenna adopts a multi-layer structure, which is conducive to the antenna obtaining broadband and excellent radiation performance; it is conducive to controlling the excitation current of the radiating unit, better satisfying the Chebyshev distribution, and achieving low side lobes.

[0030] It should be further explained that the bump structure in the feed waveguide layer can improve the reflection coefficient and reduce the side lobe. The concave-convex ridge structure can widen the bandwidth and reduce beam deflection.

[0031] Preferably, the ridge waveguide resonant cavity may be rectangular, curved and long, or the like.

[0032] Preferably, the shape of the horn mouth is a fan-shaped, pyramidal, conical or corrugated horn.

[0033] It should be noted that the radiation patterns in the vertical and horizontal directions can be adjusted by changing the height, opening, and relative position of the horn mouth to the slot.

[0034] Preferably, the pair of C-shaped metal walls are arranged on both sides of the narrow side of the radiation layer and are symmetrical about the center of the radiation layer; Preferably, the C-shaped metal wall comprises a bending structure that can be bent at any arc.

[0035] Preferably, the bending structure may be a 90-degree bending structure.

[0036] It should be noted that the bending structure is used to achieve the effect of narrowing the beam and improving the gain.

[0037] Preferably, the radiation layer and the slot layer are a metal layer, and the feeding waveguide layer is a metal layer.

[0038] It should be noted that Figure 1 The antenna shown is divided into a three-layer metal structure, but in actual production and processing, the radiation layer and the gap layer can be processed and formed as one layer, and the feeding waveguide layer is processed separately to form a double-layer metal structure as a whole, which can reduce the number of steps, reduce costs, and improve the antenna processing yield.

[0039] Preferably, the oblique slit is a rectangle or an irregular trapezoid.

[0040] Preferably, the plurality of oblique slits are arranged along the longitudinal center line of the slot layer, and the distance between two adjacent oblique slits is in the range of [0.5λg,λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

[0041] It should be noted that the distance range between adjacent slant slots among the plurality of slant slots is [0.5λg,λg], which can ensure that all slant slots can be excited in phase while avoiding the occurrence of grating lobes in the antenna pattern.

[0042] Preferably, the plurality of protrusions are centrally symmetrically arranged with respect to the center of the ridge waveguide resonant cavity, and the distance between adjacent protrusions is [0.25λg, 0.75λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

[0043] Preferably, the shape of the protrusion is rectangular, triangular or trapezoidal.

[0044] Preferably, the shape of the concave-convex ridge is a periodic corrugated structure, and the corrugated structure can be a rectangular, triangular or sinusoidal corrugation.

[0045] In order to facilitate understanding of the technical solution and structure of the above-mentioned 45-degree polarized waveguide slot antenna, another embodiment of the present application specifically discloses a 45-degree polarized waveguide slot antenna for a 77 GHz millimeter-wave vehicle-mounted radar, such as Figure 2 As shown, the antenna is composed of three layers of metal plates, which are, from top to bottom, a radiation layer 1, a slot layer 2, and a feeding waveguide layer 3, and each layer is seamlessly bonded.

[0046] Figure 3 It is a top view of the radiation layer 1; the radiation layer 1 is provided with five hollow-structured bell mouths opening upward, namely the first bell mouth 1AA, the second bell mouth 1AB, the third bell mouth 1AC, the fourth bell mouth 1AD, and the fifth bell mouth 1AE; a pair of C-shaped metal walls 1B are provided on both sides of the narrow side of the radiation layer 1.

[0047] Figure 4 It is a top view of the slot layer 2; the slot layer 2 is provided with five rectangular slits arranged longitudinally in a hollow structure, namely the first slit 2AA, the second slit 2AB, the third slit 2AC, the fourth slit 2AD, and the fifth slit 2AE; the upper surface of the slot layer 2 is seamlessly bonded to the lower surface of the radiation layer 1; the distance range between adjacent slits is [0.5λg,λg]; λg is the waveguide wavelength of the ridge waveguide resonant cavity 3A at the target frequency; for the convenience of manufacturing, the widths of the five slits are all greater than 0.5mm, and their lengths are all greater than 1.5mm.

[0048] Figure 5It is a top view of the feeding waveguide layer 3; the feeding waveguide layer 3 is provided with a rectangular ridge waveguide resonant cavity 3A; the side wall of the ridge waveguide resonant cavity 3A is provided with four rectangular protrusions, namely a first protrusion 3AA, a second protrusion 3AB, a third protrusion 3AC and a fourth protrusion 3AD, and all the protrusions are quasi-center symmetrical about the ridge waveguide resonant cavity 3A; the distance between the protrusions is [0.25λg, 0.75λg]; a central ridge 3AE is set at the bottom of the ridge waveguide resonant cavity 3A; a rectangular waveguide opening 3AF is opened in the ridge waveguide resonant cavity 3A; the upper surface of the feeding waveguide layer 3 and the lower surface of the slot layer 2 are seamlessly bonded; the total length of the ridge waveguide resonant cavity 3A is [18mm, 20mm], the width is [4mm, 5mm], and the height is [1mm, 2mm].

[0049] The rectangular waveguide opening 3AF is used to feed the feeding waveguide layer 3, and the feeding waveguide layer 3 couples and feeds the radiation layer 1 through the slot layer 2; wherein, the radiation layer 1 and the slot layer 2 can be processed as one layer, and the feeding waveguide layer 3 can be processed separately, so as to reduce the processing cost and reduce the processing error.

[0050] In this embodiment, by setting a ridge waveguide resonant cavity 3A on the feeding waveguide layer 3, the effect of feeding the five slots in series is achieved; according to the current distribution on the upper surface of the ridge waveguide resonant cavity 3A, the position where the current direction is in phase is selected to achieve in-phase excitation; the five oblique slots cut the surface current on the ridge waveguide resonant cavity 3A, and the electric field is perpendicular to the long side of the oblique slot, thereby realizing a 45-degree polarized wave; by changing the size of the four bumps and the distance and relative position of the offset center line of the five oblique slots, the electric field distribution of the center line of the upper surface of the radiation layer 1 can better meet the Chebychev distribution, thereby achieving the purpose of low side lobe of the beam; by changing the height, opening, and relative position of the horn mouth to the slot, the radiation pattern in the vertical and horizontal directions can be adjusted.

[0051] The 45-degree polarized waveguide slot antenna of this embodiment is simulated and calculated to obtain a simulated |S11| curve, such as Figure 6 As shown. Figure 6 It can be seen that the -10 dB impedance bandwidth of the antenna obtained by simulation is 75.3 GHz-83.6 GHz. Figure 7 is the simulated radiation pattern of the antenna in the horizontal plane (Phi = 0 degrees) at 78.5 GHz. The solid line and dashed line represent the main polarization and cross-polarization patterns, respectively. Figure 7 It can be seen that at 78.5 GHz, the antenna's 15 dB beamwidth can reach 122 degrees, and the cross-polarization ratio in the radiation direction is less than -20 dB. Figure 8 is the simulated radiation pattern of the vertical plane (Phi = 90 degrees) of the antenna at 78.5 GHz. The solid line and dashed line represent the main polarization and cross-polarization patterns, respectively. Figure 8It can be seen that at 78.5 GHz, the antenna sidelobe level is less than -20 dB, and the cross-polarization ratio in the radiation direction is less than -20 dB. Fig. 9 The frequency gain curve of the antenna shows that within the frequency range of 76-81 GHz, the gain of the antenna is greater than 16.7 dBi, and the peak value can reach 17.4 dBi. It can be seen that the antenna disclosed in this embodiment has excellent performances such as wide bandwidth, high gain, wide beam, low side lobe and low cross polarization within the frequency band, which meets the characteristics required by millimeter wave vehicle-mounted radar antennas. In addition, the antenna structure of this embodiment is designed based on the requirements of domestic production processes, and has excellent performance while being simple in structure and easy to process.

[0052] In summary, the embodiment of the present application provides a 45-degree polarized waveguide slot antenna, which includes several seamlessly bonded metal layers, and the metal layers are respectively a radiation layer, a slot layer and a feeding waveguide layer; the radiation layer is provided with a pair of C-shaped metal walls, and a plurality of horn mouths are provided at the bottom; the slot layer is provided with a plurality of slanted slits arranged parallel to each other, and the angle between the longitudinal center line of the slanted slit and the longitudinal center line of the slot layer is 45 degrees, and the plurality of slanted slits correspond to the plurality of horn mouths one by one; the feeding waveguide layer is provided with a ridge waveguide resonant cavity, and a plurality of protrusions are provided on the inner side of the cavity side wall, and a periodic concave-convex ridge is provided at the bottom center of the feeding waveguide layer; a rectangular feeding waveguide mouth is provided at one end of the narrow side of the cavity side wall. The present application achieves the radiation performance of wide bandwidth, high gain, low side lobe and low cross-polarization through the antenna with multi-layer metallization structure, and can be widely used in communication systems such as millimeter wave satellites and radars.

[0053] In the several embodiments provided in the present application, it should be understood that the disclosed method can also be implemented in other ways. The method embodiments described above are merely illustrative.

[0054] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0055] Although the implementation methods disclosed in this application are as above, the above contents are only the implementation methods adopted for facilitating the understanding of this application, and are not intended to limit this application. Any technician in the technical field to which this application belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application, but the scope of patent protection of this application shall still be based on the scope defined in the attached claims.

Claims

1. A 45-degree polarized waveguide slot antenna, characterized in that: The 45-degree polarized waveguide slot antenna comprises a plurality of seamlessly bonded metal layers, wherein the metal layers are respectively a radiation layer, a slot layer and a feeding waveguide layer; The radiation layer is provided with a pair of C-shaped metal walls, and a plurality of flared openings are provided at the bottom; The slot layer is provided with a plurality of oblique slots arranged parallel to each other, the angle between the longitudinal center line of the oblique slot and the longitudinal center line of the slot layer is 45 degrees, and the plurality of oblique slots correspond to the plurality of bell mouths one by one; The feed waveguide layer is provided with a ridge waveguide resonant cavity, the inner side of the cavity side wall is provided with a plurality of convex blocks, and the bottom center of the feed waveguide layer is provided with periodic concave-convex ridges; a rectangular feed waveguide opening is provided at one end of the narrow side of the cavity side wall.

2. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The shape of the horn mouth is a fan-shaped, pyramidal, conical or corrugated horn.

3. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The pair of C-shaped metal walls are arranged on both sides of the narrow side of the radiation layer and are symmetrical with respect to the center of the radiation layer.

4. The 45-degree polarized waveguide slot antenna according to claim 3, characterized in that: The C-shaped metal wall includes a bending structure that can be bent at any arc.

5. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The radiation layer and the slot layer are a metal layer, and the feeding waveguide layer is a metal layer.

6. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The oblique slit is a rectangle or an irregular trapezoid.

7. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The plurality of oblique slits are arranged along the longitudinal center line of the slot layer, and the distance between two adjacent oblique slits is in the range of [0.5λg,λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

8. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The plurality of protrusions are centrally symmetrically arranged with the center of the ridge waveguide resonant cavity as a reference, and the distance between adjacent protrusions is [0.25λg, 0.75λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency. 9 . The 45-degree polarized waveguide slot antenna according to claim 1 , wherein the protrusion is in a rectangular, triangular or trapezoidal shape.

10. The 45-degree polarized waveguide slot antenna according to claim 1, characterized in that: The shape of the concave-convex ridge is a periodic corrugated structure, and the corrugated structure can be a rectangular, triangular or sinusoidal corrugation.

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