CN118213741A

CN118213741A - Millimeter wave radar antenna and angle radar

Info

Publication number: CN118213741A
Application number: CN202211636907.8A
Authority: CN
Inventors: 张魏; 王震; 戚健庭
Original assignee: China Automotive Innovation Co Ltd
Current assignee: China Automotive Innovation Co Ltd
Priority date: 2022-12-16
Filing date: 2022-12-16
Publication date: 2024-06-18

Abstract

The present invention relates to a millimeter wave radar antenna and an angular radar, the millimeter wave radar antenna comprising: the dielectric layer is provided with a first side and a second side which are arranged oppositely; the grounding layer is positioned on the first side of the dielectric layer; a radiation layer on a second side of the dielectric layer, comprising: the radiation area comprises a row of double-slit units which are symmetrically arranged along the central axis of the radiation area, and each double-slit unit comprises a first slit and a second slit; a feeder line region extending outwardly from a middle position of the radiation region; a plurality of metallized through holes penetrating the dielectric layer to connect with the ground layer and the slit layer; a plurality of metallized through holes are arranged at intervals around the edge of the integral area formed by the radiation area and the feeder area to form equivalent side walls; the equivalent side wall is provided with an opening at the end of the feeder region for connecting the feeder. The angle radar includes a housing and a millimeter wave radar antenna housed within the housing. The invention can simultaneously have enough beam width, wider antenna working bandwidth, higher gain at large angle and smaller area or volume.

Description

Millimeter wave radar antenna and angle radar

Technical Field

The application relates to the technical field of radars, in particular to a millimeter wave radar antenna and an angle radar.

Background

With the development of the intelligent automobile field, vehicle-mounted angle radars are appeared. The vehicle-mounted angle radar is used as a medium-short distance radar in application scenes such as blind area monitoring, side lane collision early warning, lane changing assistance and the like, and the antenna is required to have a wide enough field of view (FOV) to detect targets in a large range. In order to have a sufficient FOV, a sufficiently wide antenna azimuth plane pattern beam width and a sufficiently wide antenna operating bandwidth are required. At the same time, on the basis of a sufficient FOV, it is also desirable that an antenna for angular radar can have a higher gain at a large angle and a smaller area or volume to facilitate miniaturization.

Millimeter waves have the advantages of strong penetrating power (not affected by smoke, fog, dust), all-weather use, and stable performance, so that it is desired to apply millimeter wave radar antennas that emit millimeter waves to angular radars. However, existing millimeter wave radar antennas have difficulty meeting the requirements of having a sufficient FOV, a higher gain at large angles, and having a smaller area or volume.

Disclosure of Invention

Based on this, it is necessary to provide a millimeter wave radar antenna and a horn radar having a sufficient antenna azimuth plane pattern beam width, a wide antenna operation bandwidth, a high gain at a large angle, and a small area or volume at the same time.

In a first aspect, the present application provides a millimeter wave radar antenna. The millimeter wave radar antenna includes: the dielectric layer is provided with a first side and a second side which are arranged oppositely; the grounding layer is positioned on the first side of the dielectric layer; a radiation layer on a second side of the dielectric layer, comprising: the radiation area comprises a row of double-slit units which are symmetrically arranged along the central axis of the radiation area, and each double-slit unit comprises a first slit and a second slit; a feeder line region extending outwardly from a middle position of the radiation region; a plurality of metallized through holes penetrating the dielectric layer to connect with the ground layer and the radiation layer; a plurality of metallized through holes are arranged at intervals around the edge of the integral region formed by the radiation region and the feeder region to form side walls; the side wall is provided with an opening at the end of the feeder region for connecting the feeder.

In one embodiment, the first slit and the second slit are arranged in parallel and perpendicular to the central axis of the radiation area.

In one embodiment, the length of the second slot is greater than the length of the first slot and equal to the waveguide wavelength of the dielectric layer.

In one embodiment, the distance between the first slit and the second slit decreases with increasing distance from the central axis.

In one embodiment, the distance between the first slit and the second slit in the two-slit unit and the distance between the center of the two-slit unit and the central axis corresponds to a taylor distribution or a chebyshev distribution.

In one embodiment, the radiating area further includes a middle slit located on a central axis of the radiating area and perpendicular to the central axis.

In one embodiment, the distance between the center of the double slit unit furthest from the central axis and the edge of the radiation region furthest from the central axis is one quarter of the waveguide wavelength of the dielectric layer; the two-slit unit furthest from the central axis and the edge of the radiation area furthest from the central axis are positioned on the same side of the central axis.

In one embodiment, the length of the radiation region in the direction of the central axis is half the waveguide wavelength of the dielectric layer.

In one embodiment, the millimeter wave radar antenna has an operating frequency range of 76 GHz-81 GHz, a beam width of greater than 150 degrees, gains at-75 degrees and +75 degrees of greater than 8.5dB, and a side lobe level of no greater than-25 dB.

In a second aspect, the present application provides a corner radar. The angle radar includes: a housing; the millimeter wave radar antenna is accommodated in the shell; the millimeter wave radar antenna includes: the dielectric layer is provided with a first side and a second side which are arranged oppositely; the grounding layer is positioned on the first side of the dielectric layer; a radiation layer on a second side of the dielectric layer, comprising: the radiation area comprises a row of double-slit units which are symmetrically arranged along the central axis of the radiation area, and each double-slit unit comprises a first slit and a second slit; a feeder line region extending outwardly from a middle position of the radiation region; a plurality of metallized through holes penetrating the dielectric layer to connect with the ground layer and the radiation layer; a plurality of metallized through holes are arranged at intervals around the edge of the integral region formed by the radiation region and the feeder region to form side walls; the side wall is provided with an opening at the end of the feeder region for connecting the feeder.

In the millimeter wave radar antenna and the angular radar, a part of the dielectric layer surrounded by the grounding layer, the radiation layer and the plurality of metallized through holes can be regarded as a rectangular waveguide, the grounding layer and the radiation layer can be respectively regarded as upper and lower waveguide walls of the rectangular waveguide, and the plurality of metallized through holes equivalently form the side walls of the rectangular waveguide. Meanwhile, in the radiation layer, the feeder line region is led out from the middle position of the radiation region. Thus, the dielectric layer, the ground layer, the radiation layer and the plurality of metallized vias together form a center fed SIW (Substrate integrated waveguide ) antenna structure. The simulation proves that the antenna structure has the following advantages: 1. the beam width of the 6dB reaches 160 degrees, and the working frequency band is 76 GHz-81 GHz, so that the wide directional diagram beam width and the wide working bandwidth (4-5 GHz) can be realized, and the FOV requirement required by the angle radar can be completely met; 2. the gain at +75 degrees can reach 8.78dB, and the gain at-75 degrees can reach 13.57dB, so that higher gain can be realized at a large angle; 3. the feeder line area is led out from the middle position of the radiation area to form a central feed structure, so that not only can the difficulty in antenna layout be reduced and the whole radar board volume be reduced, but also the structure can be compatible with two feed modes of a SIW feeder line and a microstrip line feeder line.

Drawings

FIG. 1 is a side view of a millimeter-wave radar antenna in one embodiment;

FIG. 2 is a top view of a millimeter-wave radar antenna in one embodiment;

FIG. 3 is a schematic diagram of a simulated S11 curve of a millimeter wave radar antenna in one embodiment;

Fig. 4 is a schematic diagram of a pattern simulation of a millimeter wave radar antenna in one embodiment;

Fig. 5 is a schematic diagram of a pattern simulation of a millimeter wave radar antenna without intermediate slots in one embodiment.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Currently, alternative types of millimeter wave radar antennas include: microstrip Patch antenna, comb combantenna, SIW slot antenna. However, these millimeter wave radar antennas have respective problems when applied to angular radars, such as: the conventional Patch antenna has the disadvantages of vertical polarization, susceptibility to interference of ground noise, and narrow bandwidth, and is difficult to have a sufficient FOV. Although a beam forming technology can be adopted for the planar array microstrip antenna to widen the bandwidth and the beam width of the azimuth plane, the technology can lead to complex design of the planar array microstrip antenna and increase of the whole area of the antenna, so that the antenna layout is difficult, and meanwhile, the volume of the whole radar board is increased. The existing combantenna is horizontally polarized, the smoothness of a horizontal gain curve is poor, and the poor smoothness of the horizontal gain curve can deteriorate azimuth angle measurement accuracy. The gain of the existing SIW slot antenna at a large angle can not meet the requirement, and the miniaturization requirement is difficult to meet at the same time. Therefore, there is a need to design a millimeter wave radar antenna that is capable of simultaneously providing sufficient antenna azimuth plane pattern beamwidth, wider antenna operating bandwidth, higher gain at large angles, and smaller area or volume.

The present application aims to realize a millimeter wave radar antenna capable of simultaneously meeting the above requirements. The millimeter wave radar antenna can be applied to electronic equipment. In one embodiment, the electronic device may be a corner radar or other module that may be provided with a millimeter wave radar antenna.

In some embodiments, an electronic device includes a housing, a millimeter wave radar antenna, and a controller. The casing forms the external structure of electronic equipment, and millimeter wave radar antenna and controller are acceptd in the casing, and the operation of electronic equipment can be controlled to the controller.

Fig. 1 is a side view of a millimeter-wave radar antenna in one embodiment. Fig. 2 is a top view of a millimeter-wave radar antenna in one embodiment.

As shown in fig. 1 and 2, an embodiment of the present application provides a millimeter-wave radar antenna 100, which includes a dielectric layer 101, a ground layer 102, a radiation layer 103, and a plurality of metallized vias 104. The dielectric layer 101 has a first side and a second side disposed opposite each other. The ground layer 102 may be disposed on a first side of the dielectric layer 101, and the radiation layer 103 may be disposed on a second side of the dielectric layer 101. The radiation layer 103 comprises a radiation region 201 and a feed line region 202. The radiation zone 201 comprises a double slit unit 203 symmetrically arranged along a central axis l of the radiation zone 201 (which extends in the y-axis direction), the double slit unit comprising a first slit and a second slit. The feeder region 202 extends outwardly from a mid-position of the radiating region 201. The plurality of metallized vias 104 extend through the dielectric layer 101 to connect with the ground layer 102 and the radiation layer 103. At the same time, a plurality of metallized vias 104 are spaced around the edge of the overall area formed by the radiating region 201 and the feed line region 202 to form equivalent sidewalls. The equivalent sidewalls are provided with openings 204 at the ends of the feeder region 202 for connection to a feeder.

In this embodiment, the dielectric layer 101 is made of an insulating material. Dielectric layer 101 may be implemented using a PCB board, such as an MT77 board. In particular, MT77 board is a low loss FR-4 process compatible board. MT77 has excellent physical properties, including a wide range of operating frequencies and higher temperature ranges, making such panels very suitable for antenna and angular radar applications.

In the present embodiment, the ground layer 102 may be used as a ground plane of the millimeter wave radar antenna 100. Meanwhile, the ground layer 102 may be used as a reflector of the antenna unit 100 to reflect electromagnetic waves onto the radiation layer 101, which is advantageous for further improving the directivity of radiation. The radiation layer 103 may be used to radiate millimeter waves outwards. The ground layer 102 and the radiation layer 103 are metal layers deposited from metal and can serve as waveguide walls so as to confine electromagnetic waves transmitted in the dielectric layer 101 to a specific region. The ground layer 102 and the radiation layer 103 are made of copper because copper has good conductivity, is easy to realize fine etching, and is stable after the preparation is completed. It should be noted that, although the ground layer 102 and the radiation layer 103 are made of copper in the present embodiment, in other embodiments, other metal materials (such as aluminum) may be used instead of copper materials to prepare the ground layer 102 and the radiation layer 103 according to actual requirements.

In this embodiment, the feeder region 202 extends outwardly from a central location of the radiating region 201 for coupling with an external feeder to direct signals input by the external feeder into the radiating region. Here, extending outward may mean extending along the central axis l of the radiation area 201 to one side of the radiation area 201. For example, fig. 2 shows that the feeder region 202 extends from a middle position of the radiation region 201 in a negative direction of the y-axis along the central axis l of the radiation region 201. Similarly, the feeder region 202 may also extend from the middle position of the radiation region 201 in the positive direction of the y-axis along the central axis l of the radiation region 201. Or extending outwardly therefrom, may also refer to feeder region 202 extending in other directions (e.g., without limitation, a direction perpendicular to the central axis l of radiating region 201, i.e., an x-axis direction) after extending a distance along the central axis l of radiating region 201 to one side of radiating region 201.

In the present embodiment, the double slit unit 203 is a unit for radiating electromagnetic waves outward in the radiation layer 101, and can be realized by etching the metal in the radiation layer 103 to expose the dielectric layer 101.

In this embodiment, the function of the metallized through holes 104 is similar to that of the ground layer 102 and the radiation layer 103, the arrangement combination of the plurality of metallized through holes 104 can be equivalent to a waveguide wall, and the transmission of electromagnetic waves in a designated area can be realized by optimizing the size and the spacing of the plurality of metallized through holes 104, in particular, when the spacing of the metallized through holes is smaller, the energy leakage is reduced.

In the millimeter wave radar antenna of the present embodiment, a part of the dielectric layer surrounded by the ground layer 102, the radiation layer 103, and the plurality of metallized through holes 104 may be regarded as a rectangular waveguide, the ground layer 102 and the radiation layer 103 may be regarded as upper and lower waveguide walls of the rectangular waveguide, respectively, and the plurality of metallized through holes 104 equivalently constitute side walls of the rectangular waveguide. Meanwhile, in the radiation layer 103, the feeder region 202 is led out from the middle position of the radiation region 201. In this way, the dielectric layer 101, the ground layer 102, the radiation layer 103 and the plurality of metallized vias 104 together form a center fed SIW antenna structure. The center-fed SIW antenna structure not only can have wider antenna azimuth plane directional pattern beam width, but also can have wider working bandwidth, and can completely meet the enough FOV required by the angle radar. At the same time, such a center fed SIW antenna structure can achieve higher gain at large angles. In addition, the center feed structure not only can reduce the difficulty of antenna layout and the whole radar board volume, but also can be compatible with two feed modes of SIW feed lines and microstrip line feed lines.

In one embodiment, the first slit and the second slit in the double slit unit are disposed in parallel and perpendicular to the central axis l of the radiation area 201.

In this embodiment, by arranging the first slot and the second slot in parallel and perpendicular to the central axis l of the radiation area 201, the first slot and the second slot can cut the current line in the rectangular waveguide in the direction parallel to the central axis l of the radiation area (i.e., the y-axis direction), so as to form excitation, thereby radiating energy outwards.

In one embodiment, the length of the second slit is greater than the length of the first slit in the double slit unit. In this embodiment, by providing two slots of different lengths, high-frequency resonance can be formed and the antenna bandwidth can be enlarged, as opposed to the case where only a single slot is provided.

It should be noted that the relative positions of the first slit and the second slit in each double slit unit are not fixed, and can be determined after optimization according to actual requirements. For example, in one embodiment, the second slot in each double slot unit is closer to the feeder region than the first slot. In other embodiments, the first slot is closer to the feeder region than the second slot in each double slot unit. In other embodiments, the second slot in the partial double slot unit is closer to the feeder region than the first slot, and the first slot in the partial double slot unit is closer to the feeder region than the second slot.

In one embodiment, the distance from the center of two double slit units 203 closest to the central axis l of the radiation region 201 to the central axis l is one waveguide wavelength, and the interval between the centers of adjacent double slit units located on the same side of the central axis l is one waveguide wavelength.

The waveguide wavelength of the dielectric layer 101 refers to a distance between two adjacent peaks or valleys of a specific electromagnetic wave propagating in the dielectric layer 101 as a waveguide, that is, a wavelength of an electromagnetic wave of a specific wave mode propagating in the waveguide. The waveguide wavelength λ _g of the dielectric layer 101 can be calculated by the following expression:

Where λ ₀ is the wavelength of a specific electromagnetic wave when it propagates in air, c is the speed of light, f ₀ is the center frequency of the antenna when it is in operation, and ε _r is the dielectric constant of the dielectric layer 101.

In this embodiment, by setting the distance from the center of the two slit units closest to the central axis l to be one waveguide wavelength and setting the interval between the centers of the adjacent slit units to be one waveguide wavelength, the radiation of the first slit and the second slit in the slit units can be in the same direction, so that the antenna performance is optimal.

In one embodiment, the length of the second slot in the two-slot unit 203, which is longer than the first slot, is equal to half the waveguide wavelength of the dielectric layer 101.

In this embodiment, it is verified through simulation that the grating lobes can be suppressed by making the length of the second slit equal to half the waveguide wavelength of the dielectric layer 101. The grating lobes are radiation lobes which are similar to the main lobes in strength due to the fact that field strengths are overlapped in phase in other directions except the main lobes. The grating lobes occupy the radiated energy, reducing the antenna gain. The object seen from the grating lobes is easily confused with the object seen from the main lobe, resulting in a blurred position of the object. The ingress of interfering signals from the grating lobes into the receiver will affect the proper operation of the communication system. Therefore, the grating lobe can be restrained to improve the antenna gain, so that the communication system can work normally.

It should be noted that, the length of the first slit having a length smaller than the second slit is generally free from other requirements. Because the function of setting the first gap is mainly to form high-frequency resonance and expand the bandwidth of the antenna, the length of the first gap can be optimized according to the requirement of the bandwidth of the antenna.

In one embodiment, the spacing between the first slit and the second slit in the two-slit unit decreases with increasing distance from the central axis of the radiation zone 201.

In one embodiment, as shown in fig. 2, the radiating element 201 comprises 10 double slit elements. If the 10 double slit units are numbered in order from left to right, the 5 th and 6 th double slit units are closest to the center of the radiation region 201, and the 1 st and 10 th double slit units are located at both ends of the radiation region 201, respectively. From the 5 th to 1 st double slit units, as the distance between each double slit unit and the center of the radiation region 201 gradually increases, the distance between the two slits (i.e., the first slit and the second slit) in each double slit unit gradually decreases, for example, the interval between the two slits in the 5 th double slit unit is larger than the interval between the two slits in the 4 th double slit unit, the interval between the two slits in the 4 th double slit unit is larger than the interval between the two slits in the 3 rd double slit unit, and so on. Similarly, from the 6 th to 10 th double slit units, as the distance from each double slit unit to the center of the radiation region 201 increases, the distance between two slits (i.e., the first slit and the second slit) in each double slit unit also decreases gradually.

In this embodiment, by gradually decreasing the interval between the first slit and the second slit in the two-slit unit from the center of the radiation region toward both ends, a lower side lobe level can be obtained. Wherein the side lobe is generally referred to as the first grating lobe. The lower the side lobe level is, the stronger the anti-interference capability of the millimeter wave radar antenna is.

In one embodiment, the distance d1 between the first slit and the second slit in the double slit unit 203 and the distance d2 between the center of the double slit unit 203 and the central axis l of the radiation area 201 conform to the taylor distribution or chebyshev distribution. The center of the double slit unit 203 refers to the geometric symmetry center thereof, that is, a point located on the center line of the double slit unit 203 and having the same distance from the first slit and the second slit.

As shown in fig. 2, in each double slit unit 203, the first slit and the second slit are symmetrical about a center line of the double slit unit, although the lengths are different. Wherein the middle line of the double slit unit 203 is parallel to the middle axis l of the radiation area 201. Thus, the center of the double slit unit 203 is located on the center line of the double slit unit 203, and the distances to the first slit and the second slit are equal (both equal to half of d 1).

In this embodiment, compared with other distribution forms, the side lobe level can be further reduced by making the distance between the two slits in the double slit unit 203 and the distance between the center of the double slit unit 203 and the center of the radiation region 201 conform to the taylor distribution or chebyshev distribution.

In one embodiment, the radiation zone 201 further comprises a middle slit 205 located on the central axis l of the radiation zone, the middle slit 205 being located between the middle two double slit units 203 closest to the central axis l, and the middle slit 205 being perpendicular to the central axis l. The intermediate gap 205 is preferably arranged symmetrically with respect to the central axis l of the radiation zone 201.

In this embodiment, by disposing the middle slot 205 on the central axis l of the radiation area 201, a short circuit structure can be formed to generate standing waves, so that the antenna radiates vertically outwards; at the same time, it can also act to suppress grating lobes and expand bandwidth, thereby achieving lower side lobe levels (see fig. 4 and 5).

In one embodiment, the intermediate slit 205 is not disposed at the center of the radiating region 201, but is disposed near the edge of the radiating region 201 that is distal from the feeder region 202. Through simulation verification, the grating lobes can be better suppressed by this arrangement than by arranging the intermediate slit 205 in the center of the radiating region 201 or near the edge of the feed line region 202.

In one embodiment, the center of the two-slit unit 203 furthest from the central axis l of the radiation zone 201 is a quarter of the waveguide wavelength of the dielectric layer 101 from the edge of the radiation zone furthest from the central axis l. Wherein the two slit units 203 furthest from the central axis l and the edges of the radiation area furthest from the central axis l are located on the same side of the central axis l. Taking the leftmost double slit unit of fig. 2 furthest from the central axis l as an example, the distance between it and the leftmost edge of the radiation zone 201 furthest from the central axis l is one quarter of the waveguide wavelength of the dielectric layer 101. Similarly, the distance between the rightmost double slit cell of fig. 2 and the rightmost edge of the radiation zone 201 furthest from the central axis l is also one quarter of the waveguide wavelength of the dielectric layer 101.

By such an arrangement, a standing wave array can be formed such that the generated beam is directed directly in front of the antenna (i.e., in a direction perpendicular to the radiation layer 103 and away from the ground layer 102), further improving the directivity of the antenna radiation.

In one embodiment, the length of the radiation region 201 in the direction of the central axis l is half the waveguide wavelength of the dielectric layer 101. By such an arrangement, the influence of grating lobes can be further reduced.

In one embodiment, the thickness of the dielectric layer 101 is preferably 0.7 to 0.9mm; the length of the radiation zone 201 in the first direction (i.e., x-axis direction) is preferably 28 to 30mm, and the length in the second direction perpendicular to the first direction (i.e., y-axis direction) is preferably 1.9 to 2.1mm; the radius of the metallized through holes 104 is preferably 0.1-0.15 mm, and the interval between adjacent metallized through holes 104 is preferably 0.4-0.6 mm; the radiation area 201 comprises an even number of double-slit units, the interval between the central lines of the two double-slit units closest to the central axis l of the radiation area is preferably 4-5 mm, and the interval between the centers of two adjacent double-slit units is preferably 2.4-3.6 mm in the double-slit units positioned on any side of the central axis l of the radiation area; in each double-slit unit, the length of the first slit is preferably 0.8-1.4 mm, and the length of the second slit is preferably 1.2-1.8 mm; the length of the intermediate gap 205 is preferably 1.9 to 2.5mm.

In a more specific embodiment, the parameters of millimeter-wave radar antenna 100 are set as follows: the dielectric layer 101 is made of MT77 plate with the thickness of 0.8 mm; the length of the radiation zone 201 in the first direction (i.e., x-axis direction) is 29mm, and the length in the second direction perpendicular to the first direction (i.e., y-axis direction) is 2mm; the radius of the metallized through holes 104 is 0.1mm, and the interval between adjacent metallized through holes 104 is 0.4mm; the radiation area 201 comprises 10 double-slit units, wherein the distance between the centers of two adjacent double-slit units is 2.8mm in the double-slit units positioned on any side of the central axis l of the radiation area; in each double-slit unit, the length of the first slit is 1.1mm, and the length of the second slit is 1.4mm; the length of the intermediate gap 205 is 2.2mm; the normalized pitch ratio of the 5 double slit units located on either side of the central axis l of the radiation area in the direction away from the central axis l is 1:0.86:0.75:0.50:0.40.

Fig. 3 is a schematic diagram of a simulation S11 curve of the millimeter wave radar antenna in the above embodiment. Wherein S11 is an antenna return loss, and is used for reflecting the reflectivity of the antenna to the input signal, and the smaller the S11 value is, the better the matching of the antenna to the input signal is. The S11 curve refers to the variation of the return loss of the antenna with the operating frequency of the antenna.

In fig. 3, the abscissa indicates the antenna frequency and the ordinate indicates the antenna return loss. As can be seen from fig. 3, in the above embodiment, the working frequency band of the millimeter wave radar antenna is 76GHz-81GHz, which indicates that the working frequency band of the antenna has a bandwidth of 4-5 GHz, and the common single microstrip antenna has a bandwidth of about 1GHz, so that the millimeter wave radar antenna of the embodiment can well expand the bandwidth.

Fig. 4 is a schematic diagram of a pattern simulation of the millimeter wave radar antenna according to the above embodiment.

In fig. 4, the abscissa is an angle, the ordinate is an antenna gain, the solid line is a pitch plane pattern curve, and the broken line is an azimuth plane pattern curve. As can be seen from the pitching plane directional diagram curve represented by the solid line, the sidelobe level of the millimeter wave radar antenna in the embodiment is below-25 dB, which indicates that the sidelobe level is low. As can be seen from the elevation pattern curve represented by the dashed line, the gain of the antenna reaches 8.78dB at +75 degrees, 13.57dB at-75 degrees, and 160 degrees in 6dB beam width. The 160-degree beam width shows that the millimeter wave radar antenna of the embodiment has a very wide beam width, and can completely meet the requirement of the antenna required by the angle radar on enough FOV by combining the working frequency band with the bandwidth of 4-5 GHz. The gain values of the antenna at +75 degrees and-75 degrees indicate that the antenna has a high gain at large angles, thereby ensuring that the antenna has good operation at large angles.

It can be seen that, in this embodiment, through the optimization design of each parameter of the millimeter wave radar, especially the optimization of the lengths and positions of the two slots in the double-slot unit and the lengths and positions of the middle slot, the two slots can work at 77GHz frequency at the same time, and obtain sufficient working bandwidth and beam width, so as to have sufficient FOV, and completely meet the gain requirement of the angle radar at a large angle, and in addition, obtain the lowest possible side lobe level.

Similar to fig. 4, the abscissa in fig. 5 is an angle, the ordinate is an antenna gain, the solid line is a pitch plane pattern curve, and the broken line is an azimuth plane pattern curve. The embodiment corresponding to fig. 5 is identical to the embodiment corresponding to fig. 4 in that the other parameter settings of the millimeter wave radar antenna are identical to the parameter settings of the embodiment corresponding to fig. 4, except that no intermediate slot is included. As can be seen from a comparison of fig. 4 and 5, the antenna pitch side lobe level in the embodiment without the intermediate slot is significantly raised compared to the embodiment with the intermediate slot. From this, it is found that the addition of the intermediate slit can suppress the antenna grating lobe and reduce the side lobe level.

In one embodiment, a corner radar is provided. The angular radar may be, for example, an angular radar. The angle radar includes: a housing; and a millimeter wave radar antenna, wherein the millimeter wave radar antenna is housed within the housing. The millimeter wave radar antenna includes: the dielectric layer is provided with a first side and a second side which are arranged oppositely; the grounding layer is positioned on the first side of the dielectric layer; a radiation layer on a second side of the dielectric layer, comprising: the radiation area comprises a row of double-slit units which are symmetrically arranged along the central axis of the radiation area, and each double-slit unit comprises a first slit and a second slit; a feeder line region extending outwardly from a middle position of the radiation region; a plurality of metallized through holes penetrating the dielectric layer to connect with the ground layer and the radiation layer; a plurality of metallized through holes are arranged at intervals around the edge of the integral region formed by the radiation region and the feeder region to form side walls; the side wall is provided with an opening at the end of the feeder region for connecting the feeder.

In one embodiment, the distance between the first slit and the second slit decreases with increasing distance from the central axis of the radiation zone.

In one embodiment, the distance between the first slit and the second slit and the distance between the center of the two-slit unit and the central axis corresponds to a taylor distribution or a chebyshev distribution.

In one embodiment, the radiating area further includes a middle slit located on the central axis and perpendicular to the central axis.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A millimeter wave radar antenna, comprising:

The dielectric layer is provided with a first side and a second side which are arranged oppositely;

The grounding layer is positioned on the first side of the dielectric layer;

a radiation layer located on a second side of the dielectric layer, comprising:

the radiation area comprises double-slit units which are symmetrically arranged along the central axis of the radiation area, and the double-slit units comprise a first slit and a second slit;

a feeder line region extending outwardly from a central location of the radiating region;

a plurality of metallized through holes penetrating through the dielectric layer to be connected with the grounding layer and the radiation layer; the plurality of metallized through holes are arranged at intervals around the edge of the integral area formed by the radiation area and the feeder area to form equivalent side walls; the equivalent side wall is provided with an opening for connecting a feeder line at the end of the feeder line region.

2. The millimeter-wave radar antenna of claim 1, wherein the first slot and the second slot are disposed in parallel and perpendicular to the central axis of the radiating area.

3. The millimeter-wave radar antenna of claim 2, wherein a length of the second slot is greater than a length of the first slot and equal to a waveguide wavelength of the dielectric layer.

4. The millimeter-wave radar antenna of claim 2, wherein a spacing between the first slot and the second slot decreases with increasing distance from the central axis of the radiating area.

5. The millimeter wave radar antenna according to claim 4, wherein a distance between the first slot and the second slot and a distance between a center of the two-slot unit to the center axis conform to taylor distribution or chebyshev distribution.

6. The millimeter-wave radar antenna according to any one of claims 1-5, wherein the radiating section further comprises a middle slot located on the central axis of the radiating section and perpendicular to the central axis.

7. The millimeter wave radar antenna according to any one of claims 1 to 5, wherein a distance between a center of a double slit unit farthest from the central axis and an edge of a radiation area farthest from the central axis is one quarter of a waveguide wavelength of the dielectric layer; the double slit unit farthest from the central axis and the edge of the radiation area farthest from the central axis are positioned on the same side of the central axis.

8. The millimeter wave radar antenna according to any one of claims 1-5, wherein a length of the radiation region in the direction of the central axis is half a waveguide wavelength of the dielectric layer.

9. The millimeter wave radar antenna according to any one of claims 1 to 5, wherein the millimeter wave radar antenna has an operating frequency range of 76GHz to 81GHz, a beam width of greater than 150 degrees, gains at-75 degrees and +75 degrees of greater than 8.5dB, and a side lobe level of not greater than-25 dB.

10. A corner radar, comprising:

A housing; and

The millimeter wave radar antenna of any one of claims 1-9, wherein the millimeter wave radar antenna is housed within the housing.