A 45-degree polarized waveguide slot antenna

Abstract

The application provides a 45-degree polarization waveguide slot antenna, which comprises several metal layers which are seamlessly attached, and the metal layers are respectively 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 a plurality of horn mouths at the bottom; the slot layer is provided with a plurality of oblique slots which are arranged in parallel with each other, the included 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 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 protrusions, and the bottom center of the feed waveguide layer is provided with a periodic concave-convex ridge; one end of the narrow side of the cavity side wall is provided with a rectangular feed waveguide port. The application realizes the radiation performance of large bandwidth, high gain, low sidelobe and low cross polarization through the multi-layer metalized structure of the antenna, and can be widely applied to millimeter wave satellite, radar and other communication systems.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, in particular to a 45-degree polarization waveguide slot antenna. BACKGROUND

[0002] At present, vehicle-mounted radars have almost become a necessary function of vehicles. The traditional millimeter wave vehicle-mounted radar antenna mainly transmits vertically polarized and horizontally polarized signals, and most vehicle-mounted sensors at the present stage also mainly transmit vertically polarized and horizontally polarized signals. Since the same signals are used, the signals will interfere with each other.

[0003] In order to enable millimeter wave radars to avoid the interference of other millimeter wave radar sensors as much as possible, one method in the prior art is to eliminate the influence of interference signals through post-processing algorithms, and another method is to reduce the received interference signal energy from the perspective of the antenna. The 45-degree polarization antenna is such an antenna with anti-interference capability. At present, most 45-degree polarization antennas are mainly made of microstrip dielectric plates. Due to the existence of dielectric loss, such type of antennas cannot achieve large bandwidth, high gain and high efficiency radiation performance. SUMMARY

[0004] In view of the above problems, the present application provides a 45-degree polarization waveguide slot antenna, which solves the technical problem that in the related art, due to the use of microstrip dielectric plates to make the antenna, there is loss and it is impossible to achieve large bandwidth, high gain and high efficiency radiation performance.

[0005] The present application provides a 45-degree polarization waveguide slot antenna, which comprises a plurality of metal layers that are seamlessly attached, and the metal layers are respectively a radiation layer, a slot layer and a feed waveguide layer.

[0006] The radiation layer is provided with a pair of C-shaped metal walls, and the bottom is provided with a plurality of horn mouths.

[0007] The slot layer is provided with a plurality of oblique slots arranged in parallel with each other, the longitudinal center line of the oblique slot and the longitudinal center line of the slot layer form an angle of 45 degrees, and the plurality of oblique slots correspond one-to-one to the plurality of horn mouths.

[0008] 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 protrusions, and the bottom center of the feed waveguide layer is provided with a periodic concave-convex ridge. One end of the narrow side of the cavity side wall is provided with a rectangular feed waveguide port.

[0009] Preferably, the shape of the horn mouth is a sector, a pyramid, a cone or a corrugated horn.

[0010] Preferably, the pair of C-shaped metal walls are arranged on both sides of the narrow side of the radiation layer and are symmetric with the center of the radiation layer.

[0011] Preferably, the C-shaped metal wall comprises a bending structure capable of being bent at any radian.

[0012] Preferably, the radiation layer and the slot layer are a layer of metal, and the feed waveguide layer is a layer of metal.

[0013] Preferably, the oblique slot is rectangular or irregular quadrilateral.

[0014] Preferably, the plurality of oblique slots are arranged along the longitudinal center line of the slot layer, and the distance between adjacent two oblique slots ranges from [0.5λg, λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

[0015] Preferably, the plurality of protrusions are symmetrically arranged with the center of the ridge waveguide resonant cavity as the 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.

[0016] Preferably, the shape of the protrusion is rectangular, triangular or trapezoidal.

[0017] Preferably, the shape of the concave-convex ridge is a periodic corrugated structure, and the corrugated structure is rectangular, triangular or sinusoidal corrugated.

[0018] The application provides a 45-degree polarized waveguide slot antenna, which comprises a plurality of seamlessly fitted metal layers, and the metal layers are respectively 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 a plurality of horn mouths at the bottom; the slot layer is provided with a plurality of oblique slots arranged in parallel to each other, the longitudinal center line of the oblique slot and the longitudinal center line of the slot layer form an angle of 45 degrees, and the plurality of oblique slots correspond one-to-one to the plurality of horn mouths; 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 protrusions, and the bottom center of the feed waveguide layer is provided with a periodic concave-convex ridge; one end of the narrow side of the cavity side wall is provided with a rectangular feed waveguide port. The application realizes the radiation performance of large bandwidth, high gain, low sidelobe and low cross-polarization through the multi-layer metalized antenna structure, and can be widely applied to millimeter wave satellite, radar and other communication systems. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can also obtain other drawings according to the provided drawings without creative labor.

[0020] Figure 1An overall structure schematic diagram of a 45-degree polarized waveguide slot antenna provided by an embodiment of the present application is shown in FIG. 1.

[0021] Figure 2 An overall structure schematic diagram of a 45-degree polarized waveguide slot antenna in another embodiment of the present application is shown in FIG. 2.

[0022] Figure 3 A top view of a radiation layer 1 of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 3.

[0023] Figure 4 A top view of a slot layer 2 of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 4.

[0024] Figure 5 A top view of a feed waveguide layer 3 of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 5.

[0025] Figure 6 A |S11| simulation curve of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 6.

[0026] Figure 7 A 78.5GHz horizontal plane (Phi=0 degree) pattern simulation curve of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 7.

[0027] Figure 8 A 78.5GHz horizontal plane (Phi=90 degree) pattern simulation curve of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 8.

[0028] Figure 9 A gain simulation curve of a 45-degree polarized waveguide slot antenna in an embodiment of the present application is shown in FIG. 9.

[0029] The following is a description of the reference signs:

[0030] 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 slant slot, 2AB-second slant slot, 2AC-third slant slot, 2AD-fourth slant slot, 2AE-fifth slant slot, 3-feed waveguide layer, 3A-ridge waveguide resonant cavity, 3AA-first protrusion, 3AB-second protrusion, 3AC-third protrusion, 3AD-fourth protrusion, 3AE-center ridge, 3AF-rectangular waveguide mouth. DETAILED DESCRIPTION

[0031] In the following, the embodiments of the present application will be described in detail with reference to the accompanying drawings and embodiments, so that how the present application applies technical means to solve technical problems and achieves corresponding technical effects can be fully understood and implemented. The embodiments of the present application and various features in the embodiments can be combined with each other without conflict, and the formed technical solutions are all within the protection scope of the present application.

[0032] As can be known from the background, at present, most 45-degree polarized antennas are mainly made of microstrip dielectric plates. Due to the existence of dielectric loss, this type of antenna cannot achieve large bandwidth, high gain and high efficiency radiation performance.

[0033] Therefore, the present application provides a 45-degree polarized waveguide slot antenna, which solves the technical problem that the antenna cannot achieve large bandwidth, high gain and high efficiency radiation performance due to the existence of loss in the related art. Embodiments

[0034] Figure 1 A 45-degree polarized waveguide slot antenna provided by the embodiments of the present application, as shown in Figure 1 The 45-degree polarized waveguide slot antenna includes a plurality of metal layers that are seamlessly attached, and the metal layers are respectively a radiation layer, a slot layer and a feed waveguide layer. Figure 1 The radiation layer, the slot layer and the feed waveguide layer are sequentially arranged from top to bottom.

[0035] It should be noted that the radiation layer, the slot layer and the feed waveguide layer can be made of metal CNC processing, or made of plastic injection molding or CNC and then surface metallization.

[0036] The radiation layer is provided with a pair of C-shaped metal walls, and the bottom is provided with a plurality of horn mouths.

[0037] It should be noted that the C-shaped metal wall can improve the radiation performance of the antenna and improve the gain of the antenna.

[0038] The slot layer is provided with a plurality of slits arranged in parallel, the longitudinal center line of the slits and the longitudinal center line of the slot layer form an angle of 45 degrees, and the plurality of slits correspond one-to-one to the plurality of horn mouths.

[0039] It should be noted that the plurality of slits cut the current of the ridge waveguide resonant cavity, and the electromagnetic waves are coupled into the plurality of horn mouths in phase, and then the electromagnetic waves are radiated to the free space with high efficiency, and the 45-degree polarized electromagnetic waves are radiated, the anti-interference ability is strong, and is not affected by most existing sensors. The horn mouth structure can realize high gain performance and realize long-distance detection function of the radar.

[0040] The feeding waveguide layer is provided with a ridge waveguide resonant cavity, the inner side of the cavity side wall is provided with a plurality of protrusions, and the bottom center of the feeding waveguide layer is provided with a periodic concave-convex ridge; one end of the cavity side wall narrow edge is provided with a rectangular feeding waveguide port.

[0041] It should be noted that the 45-degree polarized waveguide slot antenna disclosed in the application covers a bandwidth of 76-81GHz, and can be used for a millimeter wave vehicle-mounted radar antenna system; the antenna can be centrally fed by a waveguide transmission line at the bottom and can be fed by a waveguide transmission line at the side edge, and the multiple feeding modes make the antenna flexible in arraying; the antenna is provided with a pair of C-shaped metal walls on the two sides of the narrow edge of the radiation layer and is symmetric to the center of the radiation layer, and the C-shaped metal walls are provided with a plurality of slots, and the slots are arranged in a staggered manner. Figure 1 It can be seen that the antenna adopts a multi-layer structure, which is beneficial to obtaining wideband and excellent radiation performance of the antenna; the antenna is beneficial to controlling the excitation current of the radiation unit, better satisfying the Chebyshev distribution, and realizing low sidelobes.

[0042] It should be further noted that the protrusion structure in the feeding waveguide layer can improve the reflection coefficient and reduce the sidelobes. The concave-convex ridge structure can widen the bandwidth and reduce the beam deflection.

[0043] Preferably, the ridge waveguide resonant cavity can be rectangular, curved strip-shaped, etc.

[0044] Preferably, the horn mouth shape is a sector-shaped, pyramid-shaped, conical-shaped or corrugated horn.

[0045] It should be noted that by changing the height, opening and relative position of the horn mouth and the slot, the vertical and horizontal radiation patterns can be adjusted.

[0046] Preferably, the pair of C-shaped metal walls are arranged on the two sides of the narrow edge of the radiation layer and are symmetric to the center of the radiation layer.

[0047] Preferably, the C-shaped metal wall comprises a bending structure capable of being bent at any radian.

[0048] Preferably, the bending structure can be a 90-degree bending structure.

[0049] It should be noted that the bending structure is used to realize the effects of narrowing the beam and improving the gain.

[0050] Preferably, the radiation layer and the slot layer are one metal layer, and the feeding waveguide layer is one metal layer.

[0051] It should be noted that Figure 1 The antenna is divided into three layers of metal structure, but in actual production and processing, the radiation layer and the slot layer can be processed and formed as one layer, and the feeding waveguide layer is separately processed, and the whole forms a double-layer metal structure, which can reduce the process, reduce the cost, and improve the antenna processing yield.

[0052] Preferably, the oblique slots are rectangular or irregular quadrilaterals.

[0053] Preferably, the plurality of oblique slots are arranged along the longitudinal center line of the slot layer, and the distance between adjacent oblique slots ranges from [0.5λg, λg]; wherein λg is the waveguide wavelength of the ridge waveguide resonant cavity at the target frequency.

[0054] It should be noted that the distance between adjacent oblique slots in the plurality of oblique slots ranges from [0.5λg, λg], which can ensure that all oblique slots are excited in phase while avoiding the appearance of grating lobes in the antenna pattern.

[0055] Preferably, the plurality of protrusions are symmetrically arranged with the center of the ridge waveguide resonant cavity as the 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.

[0056] Preferably, the shape of the protrusions is rectangular, triangular, or trapezoidal.

[0057] Preferably, the shape of the protrusions is a periodic corrugated structure, which can be rectangular, triangular, or sinusoidal.

[0058] In order to facilitate the understanding of the technical solutions and structures 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 77GHz millimeter wave vehicle-mounted radar, as shown in Figure 2 As shown in the figure, the antenna is composed of three metal plates, from top to bottom are the radiation layer 1, the slot layer 2, and the feed waveguide layer 3, and there is no seam between each layer.

[0059] Figure 3 is a top view of the radiation layer 1; the radiation layer 1 is provided with five open upward horn mouths of hollow structures, which are the first horn mouth 1AA, the second horn mouth 1AB, the third horn mouth 1AC, the fourth horn mouth 1AD, and the fifth horn mouth 1AE; the radiation layer 1 is provided with a pair of C-shaped metal walls 1B on both sides of the narrow edge.

[0060] Figure 4 is a top view of the slot layer 2; the slot layer 2 is provided with five longitudinally arranged rectangular oblique slots of hollow structures, which are the first oblique slot 2AA, the second oblique slot 2AB, the third oblique slot 2AC, the fourth oblique slot 2AD, and the fifth oblique slot 2AE; the upper surface of the slot layer 2 is seamlessly attached to the lower surface of the radiation layer 1; the distance between adjacent oblique slots ranges from [0.5λg, λg]; λg is the waveguide wavelength of the ridge waveguide resonant cavity 3A at the target frequency; in order to facilitate manufacturing, the width of the five oblique slots is greater than 0.5mm, and the length is greater than 1.5mm.

[0061] Figure 5It is a top view of the feed waveguide layer 3; the feed 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, which are a first protrusion 3AA, a second protrusion 3AB, a third protrusion 3AC and a fourth protrusion 3AD, and all the protrusions are centrally symmetric about the ridge waveguide resonant cavity 3A; the distance between the protrusions is [0.25λg, 0.75λg]; a central ridge 3AE is arranged at the bottom of the ridge waveguide resonant cavity 3A; a rectangular waveguide port 3AF is arranged on the ridge waveguide resonant cavity 3A; the upper surface of the feed waveguide layer 3 and the lower surface of the slot layer 2 are seamlessly connected; the total length of the ridge waveguide resonant cavity 3A is [18mm, 20mm], the width is [4mm, 5mm], and the height is [1mm, 2mm].

[0062] The rectangular waveguide port 3AF is used for feeding the feed waveguide layer 3, and the feed waveguide layer 3 is coupled to 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 feed waveguide layer 3 can be processed separately, thereby reducing the processing cost and reducing the processing error.

[0063] In this embodiment, by arranging the ridge waveguide resonant cavity 3A on the feed waveguide layer 3, the function of feeding the five slots in series is realized; according to the current distribution on the upper surface of the ridge waveguide resonant cavity 3A, the positions with the same phase of the current direction are selected to realize the same phase excitation; the five slits cut the surface current on the ridge waveguide resonant cavity 3A, and the electric field is perpendicular to the long side of the slits, thereby realizing the 45-degree polarized wave; by changing the size of the four protrusions and the distance and relative position of the five slits offset from the center line, the electric field distribution on the center line of the upper surface of the radiation layer 1 can better meet the Chebyshev distribution, thereby realizing the purpose of low sidelobe of the beam; by changing the height, opening and relative position of the horn port, the vertical and horizontal radiation patterns can be adjusted.

[0064] The simulation calculation of the 45-degree polarized waveguide slot antenna of this embodiment is carried out, and the simulation |S11| curve is as shown in Figure 6 It can be seen from Figure 6 that the -10 dB impedance bandwidth of the antenna obtained by simulation is 75.3 GHz-83.6 GHz. Figure 7 It is the simulation radiation pattern of the antenna in the horizontal plane (Phi = 0 degree) at the frequency point of 78.5 GHz, and the solid line and the dashed line respectively represent the patterns of the main polarization and the cross polarization; it can be seen from Figure 7 that at 78.5 GHz, the 15 dB beam width of the antenna is 122 degrees, and the cross polarization ratio of the radiation direction is less than -20 dB. Figure 8 It is the simulation radiation pattern of the antenna in the vertical plane (Phi = 90 degree) at the frequency point of 78.5 GHz, and the solid line and the dashed line respectively represent the patterns of the main polarization and the cross polarization; it can be seen from Figure 8It can be seen that the antenna side lobe level is less than -20 dB and the cross polarization ratio of the radiation direction is less than -20 dB at 78.5 GHz. Figure 9 For the frequency gain curve of the antenna, the gain of the antenna is greater than 16.7 dBi in the frequency range of 76-81 GHz, and the peak value can reach 17.4 dBi. It can be seen that the antenna disclosed in the embodiment has excellent performances such as wide frequency band, high gain, wide beam, low side lobe and low cross polarization, and meets the required characteristics of the millimeter wave vehicle-mounted radar antenna. Moreover, the antenna structure of the embodiment is designed from the domestic production process requirements, and has excellent performances, simple structure and easy processing.

[0065] In summary, the 45-degree polarized waveguide slot antenna provided in the embodiment of the application comprises a plurality of metal layers that are seamlessly attached, the metal layers are respectively 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 a plurality of horn mouths at the bottom; the slot layer is provided with a plurality of slits arranged in parallel with each other, the longitudinal center line of the slits and the longitudinal center line of the slot layer form an angle of 45 degrees, and the plurality of slits correspond one-to-one to the plurality of horn mouths; 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 protrusions, and the bottom center of the feed waveguide layer is provided with a periodic concave-convex ridge; one end of the narrow side of the cavity side wall is provided with a rectangular feed waveguide port. The antenna with the multi-layer metal structure realizes the radiation performance of wide band, high gain, low side lobe and low cross polarization, and can be widely applied to millimeter wave satellite, radar and other communication systems.

[0066] In several embodiments provided in the embodiment of the application, it should be understood that the disclosed method can also be implemented by other ways. The method embodiments described above are only illustrative.

[0067] It should be noted that, in this document, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or further include elements inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0068] Although the embodiments of the present application have been disclosed with reference to the above embodiments, the above embodiments are merely used to facilitate understanding of the present application and are not used to limit the present application. Any person skilled in the art, without departing from the spirit and scope of the present application, can make any modification and change in the form and details of the embodiments, but the patent protection scope of the present application should be subject to the scope defined by the appended 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 feed 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 slit layer is provided with a plurality of oblique slits arranged parallel to each other, the angle between the longitudinal center line of the oblique slit and the longitudinal center line of the slit layer is 45 degrees, and the plurality of oblique slits 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 protrusions, and the bottom center of the feed waveguide layer is provided with a periodic concave-convex ridge; a rectangular feed waveguide port is provided at one end of the narrow side of the cavity side wall.

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

3. The 45-degree polarization waveguide slot antenna according to claim 1, wherein: 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 polarization waveguide slot antenna according to claim 3, wherein: The C-shaped metal wall includes a bending structure that can be bent at any arc.

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

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

7. The 45-degree polarization waveguide slot antenna according to claim 1, wherein: 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 polarization waveguide slot antenna according to claim 1, wherein: 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 polarization waveguide slot antenna according to claim 1 , wherein the protrusion is in a rectangular, triangular or trapezoidal shape.

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

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