Antenna cover design method and millimeter wave radar

Abstract

The application belongs to the technical field of vehicle-mounted millimeter wave radar, and particularly relates to an antenna cover design method and a millimeter wave radar. The method comprises the following steps: obtaining antenna parameters; determining initial positions of recessed points of each groove on the antenna cover in a first direction, so that the initial positions of any one of the recessed points in the first direction are located between boundary lines of radiation angles of two of the antennas; determining a cross-sectional profile of the groove; establishing a three-dimensional model of the antenna cover according to the initial positions of the recessed points in the first direction and the cross-sectional profile of the groove; simulating the three-dimensional model of the antenna cover, and adjusting the positions of the recessed points in the first direction until the gains of the antennas in any direction within the radiation angle range in the simulation result meet preset requirements. The application improves the antenna gain in a large-angle direction, and improves the identification ability of the radar to large-angle obstacles.

Description

Technical Field

[0001] This invention belongs to the field of vehicle-mounted millimeter-wave radar technology, specifically relating to an antenna radome design method and a millimeter-wave radar. Background Technology

[0002] With the development of intelligent assisted driving technology, automotive millimeter-wave radar is widely used in automotive ADAS systems to detect target information of surrounding objects, such as distance, speed, angle, and size. This information provides relevant warnings during driving or parking, greatly improving driving safety. For perceiving information around the vehicle, an intelligent car typically needs to be equipped with multiple radars, such as forward ranging radar and angle measurement radar (hereinafter referred to as angle radar). Among them, angle radar is mainly installed at the four corners of the car to detect objects at close range. In order to perceive objects within a wider angular range and avoid blind spots, higher requirements are placed on the performance of the radar antenna. Generally, the wider the horizontal angle of the antenna, the larger the detection range. Automotive millimeter-wave angle radar plays a key role in blind spot monitoring, lane change assist, parking assist, and other application scenarios. Automotive millimeter-wave radar mainly consists of seven basic parts: circuit board, antenna, radome, metal back cover, thermal conductive adhesive, waterproof and breathable plug, and screws. To achieve better beamforming, radar antennas are typically designed on printed circuit boards (PCBs), using a suitable high-frequency dielectric substrate as the carrier. They typically have a three-layer structure: one layer for the antenna fabrication, one layer for the dielectric substrate, and one layer for the ground plane. Besides the antenna design itself, which plays a deterministic role in the antenna pattern, the design of the radome also affects the antenna's radiation pattern, especially the gain at large angles.

[0003] Currently, the radome design commonly used in the industry for millimeter-wave radar is still a simple planar structure. This design is simplistic, focusing only on structural protection without considering the impact on antenna performance. This antenna structure exhibits significant power dips at large azimuth angles in angle radar. In practical applications, this dip in the antenna pattern leads to a decrease in the detection performance of the angle radar, such as the inability to identify targets at that angle, resulting in blind spots. How to reduce the impact of the radome on antenna performance, avoid azimuth dips and sudden drops, and thus improve the detection range of angle radar remains a design challenge and a key problem that needs to be overcome in the industry. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an radome design method and millimeter-wave radar that can reduce the power dip at the radar detection boundary and improve the radar boundary detection performance.

[0005] To achieve the above and other related objectives, the present invention provides a radome design method, comprising the following steps: Obtain antenna parameters; Based on the antenna parameters, determine the initial position of the recessed point of each groove on the radome in the first direction, such that the initial position of any one of the recessed points in the first direction is located between the boundary lines of the radiation angles of two of the antennas. The recessed point is the point on the inner side of the groove that is closest to the PCB board where the antenna is located. The first direction is a direction that is perpendicular to the length direction of the antenna and parallel to the PCB board. The cross-sectional profile of the groove is determined based on the preset position of the recessed point in the second direction, the angle between the two side walls of the groove and the normal of the PCB board, and the thickness of the radome. The second direction is the normal of the PCB board. Based on the initial position of the recessed point in the first direction and the cross-sectional profile of the groove, a three-dimensional model of the radome is established. The three-dimensional model of the radome is simulated, and the position of the recessed point in the first direction is adjusted until the gain of each antenna in any direction within the radiation angle range meets the preset requirements in the simulation results. The position of the recessed point at this time is taken as the final position of the recessed point, and the radome design is completed.

[0006] In an optional embodiment of the present invention, the following steps are further included: The two corners of the top edge of the antenna cover, which are parallel to the antenna, are rounded.

[0007] In an optional embodiment of the present invention, the step of determining the initial position of the recessed point of each groove on the radome in a first direction according to the antenna parameters, such that the initial position of any one of the recessed points in the first direction is located between the boundary lines of the radiation angles of two of the antennas, includes: Based on the number of antennas and their positional distribution in the first direction, determine the number of recessed points and their original coordinates in the first direction. Determine two strongly correlated antennas for the depression point, wherein the strongly correlated antennas are the two antennas whose radiation angle boundary line is closest to the depression point; Based on the boundary line of the maximum radiation angle of the two strongly correlated antennas, determine the range of coordinate values ​​of the indentation point in the first direction. Choose any value from the range of coordinates of the depression point in the first direction as the initial position of the depression point in the first direction.

[0008] In an optional embodiment of the present invention, the step of determining the two strongly correlated antennas of the indentation point includes: Based on the original coordinates of the depression point, determine the antenna pair associated with the depression point. The antenna pair associated with the depression point refers to the area where the depression point is located within the intersection of the radiation angles of the two antennas in the antenna pair. Select the antenna pair with the smallest radiation angle crossover range from each group of antenna pairs, and use the two antennas in this antenna pair as the strongly correlated antennas of the recessed point.

[0009] In an optional embodiment of the present invention, the step of determining the cross-sectional profile of the groove based on the preset position of the recessed point in the second direction, the angle between the two side walls of the groove and the normal of the PCB board, and the thickness of the radome includes: Based on the thickness of the radome and the angle between the two side walls of the groove and the normal of the PCB board, calculate the distance between the recessed point and the lowest point of the top surface of the groove in the second direction; The position of the lowest point of the top surface of the groove in the second direction is determined based on the distance between the recessed point and the lowest point of the top surface of the groove in the second direction, and the position of the recessed point in the second direction. The top surface outline of the groove is determined based on the position of the lowest point of the top surface of the groove in the second direction and the angle between the two side walls of the groove and the normal of the PCB board. The bottom contour line of the groove is determined based on the position of the recessed point in the second direction and the angle between the two side walls of the groove and the normal of the PCB board.

[0010] In an optional embodiment of the present invention, the step of simulating the three-dimensional model of the radome and adjusting the position of the recessed point in the first direction until the gain of each antenna in any direction within the radiation angle range in the simulation results meets the preset requirements includes: The three-dimensional model of the radome is simulated, and the position of the recessed point in the first direction is adjusted until the gain of each antenna in any direction within the radiation angle range is greater than 0dB in the simulation results.

[0011] In an optional embodiment of the present invention, the included angle between the two groove walls of the groove and the normal of the PCB board is 60°-80°.

[0012] In an optional embodiment of the present invention, the thickness of the radome is uniform at all locations, and the thickness of the radome is an integer multiple of half the wavelength of the electromagnetic wave signal transmitted or received by the antenna when it propagates within the radome material.

[0013] To achieve the above and other related objectives, the present invention also provides a millimeter-wave radar, comprising: Base; A PCB board is mounted on the base, and multiple antennas are formed on the PCB board, with each antenna arranged side by side at intervals. An antenna radome, which is connected to the base, covers the outer side of the PCB board; The radome includes a flat plate portion parallel to the PCB board and a groove formed in the flat plate portion. The groove is strip-shaped, and the length direction of the groove is parallel to the length direction of the antenna. The groove is set at the boundary of the radiation angle of the antenna.

[0014] In an optional embodiment of the present invention, multiple grooves are provided, and each groove corresponds to the boundary setting of the radiation angle of the two antennas.

[0015] In an optional embodiment of the present invention, the edge of the radome parallel to the length direction of the antenna is provided with rounded corners.

[0016] The technical advantages of this invention are as follows: By changing the shape of the radome, this invention changes the incident angle of electromagnetic waves on different medium surfaces, thereby changing the angle after penetrating the radome. This is also an important principle for improving the gain at large angles in this design. The optimized design of the radome structure in this solution improves the antenna gain at large angles and enhances the radar's ability to identify obstacles at large angles. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the refraction principle of an existing radome; Figure 2 This is a schematic diagram of the improved antenna radome refraction principle of the present invention; Figure 3 This is a schematic diagram of the antenna distribution of a millimeter-wave radar provided in an embodiment of the present invention; Figure 4 This is an exploded view of the millimeter-wave radar provided in an embodiment of the present invention; Figure 5 This is a cross-sectional view of the radome provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the grooves in the radome and the antenna radiation angle distribution provided in an embodiment of the present invention; Figure 7 These are the horizontal radiation patterns of the millimeter-wave radar before and after the radome modification provided in the embodiments of the present invention; Figure 8 This is a flowchart of the radome design method provided in an embodiment of the present invention; Figure 9 This is a flowchart of the groove position determination method provided in the embodiments of the present invention. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0020] When electromagnetic waves penetrate a medium, they undergo refraction and reflection. Different angles of entry into the medium result in different refraction deflections and different loss paths. Impedance mismatch at the radome boundary causes electromagnetic wave reflection to occur at the boundary of the mismatch plane, which can be considered as the boundary between two media with different dielectric properties, i.e., media with different dielectric constants. The wall thickness of the radome plays a crucial role in achieving optimal performance of millimeter-wave radar sensors. It is important to ensure that the radome wall thickness is an integer multiple of 1 / 2 of the radar wavelength so that the radome becomes almost transparent in the millimeter-wave frequency range.

[0021] A common design in the industry is a rectangular radome. The electrical distance through the radome is equivalent to the thickness of the radome walls. However, this distance increases with the angle of arrival, leading to higher angle estimation errors. The reason behind this phenomenon is that if the radome wall thickness is designed to be λ / 2 (half a wavelength), the round trip of the radar signal reflected from the inner wall surface and then back from the outer wall surface will introduce a net 180° phase shift from the inner wall. Therefore, on the line of sight of the rectangular radome, the reflections from the inner wall will be canceled out because they are asynchronous, resulting in lower net reflection. However, when moving from the sight to higher incident angles of arrival, the distance traveled by the millimeter-wave signal is greater than the "optimal thickness" or "half a wavelength." This will produce multiple reflections at the radome interface boundaries, causing ripples in the antenna radiation pattern and resulting in nulls. In the angle estimation of these targets, the incident error can lead to even higher null errors. This effect can be offset by gradually thinning the radome walls towards the radar field of view—that is, thinning the radome as the angle increases. However, this design of gradually thinning at the edges is impractical and would affect the strength of the radome.

[0022] When electromagnetic waves propagate perpendicularly to the radome medium, and the radome thickness is an integer multiple of λg / 2, energy loss is minimized. However, when multiple antennas are present, the points on the radiation circles of each antenna form the optimal radome profile. But because the antennas are positioned differently, the radiation circles will not perfectly coincide or be tangent, meaning it's impossible to obtain a radome shape that simultaneously satisfies the optimal radiation of multiple antennas. To maximize overall energy radiation, the best practice for a single-layer radome is a bullet shape, minimizing the angle of incidence of the radiated electromagnetic waves from all antennas as much as possible. While this bullet-shaped radome minimizes energy loss, it places high demands on size; the radome's height exceeding the antenna's height is several times that of conventional designs. This large-size design is clearly unsuitable for automotive millimeter-wave radar applications.

[0023] Please see Figure 1 As shown, the radome design commonly used in the industry for millimeter-wave radar is still a simple planar structure. This design is simple, only considering structural protection, without considering the impact on antenna performance. This antenna structure exhibits a significant power dip at large azimuth angles in angle radar. In practical applications, this antenna pattern dip leads to a reduction in the detection range and a decrease in detection performance of the angle radar. For example, it may be unable to identify targets at that angle, creating blind spots in detection. Figure 1 The dashed arrow in the middle represents the expected detection range of the corner radar, while the actual arrow represents the actual detection range. As can be seen from the figure, the detection range of the corner radar is significantly reduced due to the refraction of the radome.

[0024] Please see Figure 2 As shown, this solution improves signal strength at large angles by modifying the shape of the radome and adding grooves in the direction of large-angle antenna radiation. This results in a shorter path for the electromagnetic waves radiated by the antenna to penetrate the radome at large angles, reducing signal loss. Figure 2 The dashed arrows represent the expected detection range, while the actual arrows represent the actual detection range. As can be seen from the figure, the detection range of the improved corner radar has been significantly enhanced.

[0025] Please see Figure 4 As shown, a millimeter-wave radar includes a base 10, a PCB board 20, and an radome 30. The PCB board 20 is mounted on the base 10, and multiple antennas 21 are formed on the PCB board 20, with each antenna 21 arranged side-by-side at intervals. The radome 30 is connected to the base 10 and covers the outer side of the PCB board 20. The radome 30 includes a flat plate portion parallel to the PCB board 20 and a groove 31 formed in the flat plate portion. The groove 31 is strip-shaped, and its length direction is parallel to the length direction of the antenna 21. The groove 31 is positioned corresponding to the boundary of the radiation angle of the antenna 21. (See reference...) Figure 2 As shown, it should be understood that this solution improves the signal strength at large angles by changing the shape of the radome 30 and adding a groove 31 in the direction of large-angle radiation of the antenna 21. This makes the path of the electromagnetic waves radiated by the antenna 21 through the radome 30 shorter and the signal loss less.

[0026] Please see Figure 5 , 6 As shown, in one specific embodiment, multiple grooves are provided, and each groove corresponds to the boundary setting of the radiation angle of the two antennas. In this embodiment, each groove can simultaneously optimize the boundary signals of the two antennas, simplifying the structure of the radome 30, while avoiding unnecessary adverse interference to the antenna signals caused by an excessive number of grooves.

[0027] Please see Figure 5 , 6 As shown, in a specific embodiment, the edge of the radome 30 parallel to the length direction of the antenna is provided with rounded corners. These rounded corners can be regarded as two semi-grooves provided at the edge of the radome 30, which can also optimize the boundary signal of the antenna 21.

[0028] Please see Figure 5 , 6 As shown, in one specific embodiment, the groove has a V-shaped cross-section, and the angle between the two walls of the groove and the normal of the PCB board 20 is 60°-80°. Furthermore, the normal thickness of the radome 30 at each location is an integer multiple of half the wavelength of the electromagnetic wave signal transmitted or received by the antenna propagating within the material of the radome 30. As described above, the wall thickness of the radome 30 is designed to be λ / 2 (half a wavelength), which will introduce a net 180° phase shift in the radar signal emitted from the inner wall during the round trip through the inner wall surface and then reflected back from the outer wall surface. The reflection from the inner wall will be canceled out, so that the radome 30 becomes almost transparent in the millimeter-wave frequency range.

[0029] Please see Figure 3 As shown, in a specific embodiment, the antenna includes a first antenna 211, a second antenna 212, a third antenna 213, a fourth antenna 214, a fifth antenna 215, and a sixth antenna 216. The first antenna 211, the second antenna 212, the third antenna 213, the fourth antenna 214, the fifth antenna 215, and the sixth antenna 216 are arranged sequentially along a first direction, which is perpendicular to the length direction of the antenna and parallel to the PCB board. The first antenna 211, the second antenna 212, the third antenna 213, and the fourth antenna 214 are receiving antennas, and the fifth antenna 215 and the sixth antenna 216 are transmitting antennas.

[0030] Please see Figure 6As shown, in one specific embodiment, the groove includes a first groove 1, a second groove 2, a third groove 3, and a fourth groove 4. The first groove 1 is located between the negative boundary lines of the radiation angles of the second antenna 212 and the third antenna 213; the second groove 2 is located between the negative boundary lines of the radiation angles of the fourth antenna 214 and the fifth antenna 215; the third groove 3 is located between the negative boundary line of the radiation angle of the sixth antenna 216 and the positive boundary line of the radiation angle of the first antenna 211; and the fourth groove 4 is located between the positive boundary lines of the radiation angles of the third antenna 213 and the fourth antenna 214.

[0031] Please see Figure 1 , 2 As shown, due to the wave refraction theorem, the main signal will be refracted at different angles when encountering different dielectric layers. This invention changes the incident angle of the electromagnetic wave on different dielectric surfaces by changing the shape of the radome 30, thereby changing the angle after penetrating the radome 30. This is also an important principle for improving the large-angle gain of this design; please refer to... Figure 7 As shown, this design optimizes the structure of the radome 30, improving the antenna gain at large angles. Simulation analysis using antenna simulation software demonstrates that this design enhances the combined gain of the transmitting and receiving antennas by more than 15dB at angles of ±80 degrees in the horizontal radiation pattern. In practical applications, this will benefit the radar's field of view (FOV) and improve its ability to identify obstacles at large angles.

[0032] Please see Figure 8 As shown, the present invention provides a design method for the radome 30 of the millimeter-wave radar, comprising the following steps: S10: Obtain antenna parameters, mainly including the spatial layout parameters between each antenna 21, such as the spacing between each antenna 21, and the wavelength, radiation angle, and other parameters of the signals transmitted and received by the antenna 21.

[0033] S20: Based on the antenna parameters, determine the initial position of the recessed point of each groove on the radome in the first direction, such that the initial position of any one of the recessed points in the first direction is located between the boundary lines of the radiation angles of two of the antennas. The recessed point is the point on the inner side of the groove that is closest to the PCB board. The first direction is a direction that is perpendicular to the length direction of the antenna and parallel to the PCB board.

[0034] Please see Figure 9 As shown, in one specific embodiment, step S20 includes: S21: Determine the number of recessed points and the original coordinates of the recessed points in the first direction based on the number of antennas and the positional distribution of the antennas in the first direction; S22: Determine two strongly correlated antennas for the indentation point, wherein the strongly correlated antennas are the two antennas 21 whose radiation angle boundary line is closest to the indentation point; S23: Determine the range of coordinate values ​​of the indentation point in the first direction based on the boundary line of the maximum radiation angle of the two strongly correlated antennas; S24: Select any value from the range of coordinate values ​​of the depression point in the first direction as the initial position of the depression point in the first direction.

[0035] The following detailed description of steps S21-S24, in conjunction with specific embodiments, is as follows: First, the initial structure of the radome 30 is constructed. The radome 30 is based on a rectangular radome 30 with rounded corners on the left and right sides. This is beneficial for antenna energy near the two edges of the radome 30 to penetrate the radome 30 with minimal loss. The radius of the rounded corners R ≥ 3.5 mm. The thickness of the radome 30, as explained in the previous theory, is preferably an integer multiple of half the wavelength of the operating frequency in the medium, named d. The normal thickness of the radome 30 at each position is d = 2.44 mm.

[0036] The fan-shaped treatment of the radome 30 involves adding grooves 31 to it. By changing the penetration distance and refraction angle of the electromagnetic waves radiated by the antenna in the middle of the radome 30, more energy can be radiated in the large-angle radiation direction, thereby achieving a higher antenna gain. Simulation observations show that the key design point lies in the selection of the position and depth of the folded grooves 31.

[0037] Please see Figure 5 As shown, this embodiment designs four grooves 1, 2, 3, and 4 from left to right. These grooves are connected by planes 5, 6, and 8. The recessed points of each groove are defined as A, B, C, and D. As a structural protective device, the radome 30 needs to be designed with a thickness ≥ d at all points, where d is an integer multiple of the half-wavelength of the operating frequency in the medium, to ensure robust protection. The distance from the inner side of planes 5, 6, and 8 of the radome 30 to the PCB board 20 is defined as h. In this embodiment, h = 3.9 mm. The distance from recessed points A, B, C, and D to the PCB board 20 is hm, where hm = 2.32 mm. Therefore, the ordinate of A, B, C, and D is 2.32 mm. Thus, A, B, C, and D = [xa, hm; xb, hm, xc, hm; xd, hm]. The final values ​​of xa, xb, xc, and xd are determined based on the following steps.

[0038] Set the original coordinates for A, B, C, and D, denoted as A0, B0, C0, D0 = [xa0, hm; xb0, hm, xc0, hm; xd0, hm]; Two strongly correlated antennas are determined for each of A0, B0, C0, and D0. As mentioned above, a total of 6 antennas 21 are set. For a given depression point, all 6 antennas 21 will affect its position setting. In this embodiment, only the 2 antennas 21 with the greatest influence are selected to determine the range of the horizontal coordinate values ​​of the depression point.

[0039] In step S22, the steps for determining the two strongly correlated antennas are as follows: Based on the original coordinates of the depression point, determine the antenna pair associated with the depression point. The antenna pair associated with the depression point refers to the area where the depression point is located within the intersection of the radiation angles of the two antennas in the antenna pair. Select the antenna pair with the smallest radiation angle crossover range from each group of antenna pairs, and use the two antennas in this antenna pair as the strongly correlated antennas of the recessed point.

[0040] Specific examples are as follows: The following uses point A as an example to illustrate the method for determining strongly correlated antennas: like Figure 6 As shown, the initial coordinates of point A are within the intersection range of the positive and negative θmax of the third antenna 213 (θmax is the preset maximum radiation angle, which is ±80° in this embodiment) and the positive and negative θmax of the second antenna 212. At the same time, they are also within the intersection range of the positive and negative θmax of the first antenna 211 and the fourth antenna 214. In order to reduce the workload of determining the simulation range in the future, the second antenna 212 and the third antenna 213, which have smaller locked intersection ranges, are selected as the strongly correlated antennas of point A. The method for determining the strongly correlated antennas of other points B, C, and D is the same.

[0041] Based on the strongly correlated antenna and the maximum radiation angle, the range of values ​​for the abscissas of A, B, C, and D is determined, i.e., the initial coordinates. Point A is to the left of the intersection point b of the ray of the third antenna 213 (-θmax, which is the preset maximum radiation angle, and is taken as ±80° in this embodiment) and the line y=hm, with the coordinates of the intersection point b being (xA1, hm), and to the right of the intersection point a of the ray of the second antenna 212 (-θmax) and the line y=hm, with the coordinates of the intersection point a being (xA2, hm). The initial coordinate range of point A, xa, is: xa∈(xA1, xA2), as shown in the figure below. Point A is to the left of the intersection point b of the -80° ray of the third antenna 213 and the line y=hm (xa<-17.25), and to the right of the intersection point a of the -80° line of the second antenna 212 and the line y=hm (xa>-23.08). The coordinates of A can be taken as (-20, 2.32).

[0042] Similarly, point B is to the left of the intersection of the -80° ray of the fifth antenna 215 and the line y=hm (xb<-7.08), and to the right of the intersection of the -80° ray of the fourth antenna 214 and the line y=hm (xb>-10.36).

[0043] Point C is to the left of the intersection of the -80° ray of the sixth antenna 216 and the line y=hm (xc<2.72), and to the right of the intersection of the +80° ray of the first antenna 211 and the line y=hm (xc>-2.42).

[0044] Point D is to the left of the intersection of the +80° ray of the fourth antenna 214 and the line y=hm (xd<16.09), and to the right of the intersection of the +80° ray of the third antenna 213 and the line y=hm (xd>9.09).

[0045] Based on the above constraints, A, B, C, and D can be defined with the following initial coordinates: A (-20, 2.32), B (-9, 2.32), C (0, 2.32), D (13, 2.32).

[0046] The antenna radome 30 design method further includes step S30: determining the cross-sectional profile of the groove based on the preset position of the recessed point in the second direction, the angle between the two side walls of the groove and the normal of the PCB board, and the thickness of the antenna radome. The second direction is the normal of the PCB board, and the position of the recessed point in the second direction can be recorded as the distance hm between the recessed point and the PCB board.

[0047] The radome 30 design method further includes step S40: establishing a three-dimensional model of the radome based on the initial position of the recessed point in the first direction and the cross-sectional profile of the groove. It should be understood that establishing the three-dimensional model of the radome requires not only the initial position of the recessed point in the first direction and the cross-sectional profile of the groove, but also other necessary parameters, such as the distance h between the inner side of the planar portion of the radome and the PCB board, and the overall length, width, and height of the radome. These parameters can be selected based on empirical values, and since these parameters are not the focus of this invention, they will not be elaborated further.

[0048] The radome 30 design method further includes S50: simulating the three-dimensional model of the radome 30 and adjusting the position of the recessed point in the first direction until the gain of each antenna 21 in any direction within the radiation angle range meets the preset requirement in the simulation results. The position of the recessed point at this point is then taken as the final position of the recessed point, and the radome 30 design is completed. In a specific embodiment, the preset requirement means that the gain of each antenna 21 in any direction within the radiation angle range is greater than 0 dB.

[0049] Steps S30-S50 will be described in detail below with reference to specific embodiments: Step S30 specifically includes: calculating the distance between the recessed point and the lowest point of the top surface of the groove in the second direction based on the thickness of the radome and the angle between the two side walls of the groove and the normal of the PCB board; determining the position of the lowest point of the top surface of the groove in the second direction based on the distance between the recessed point and the lowest point of the top surface of the groove in the second direction and the position of the recessed point in the second direction; determining the top surface contour line of the groove based on the position of the lowest point of the top surface of the groove in the second direction and the angle between the two side walls of the groove and the normal of the PCB board; determining the bottom surface contour line of the groove based on the position of the recessed point in the second direction and the angle between the two side walls of the groove and the normal of the PCB board. A specific example is as follows: Based on the initial coordinates, determine the polygonal lines of each groove 31. Let the angle between the polygonal line and the vertical center line of the radar be aerfa, which is a preset value that can be confirmed empirically, such as 60 degrees to 80 degrees. Then the slope of the polygonal line is ±cot(aerfa). From this, the polygonal lines passing through points A, B, C, and D can be drawn. From this, the inner and outer lines of the radome 30 can be determined. Given that the thickness of the radome 30 is d = 2.44 mm, the outer line is the inner line shifted dm in the positive y-axis direction, where dm = d / sin(aerfa) = 2.63 mm. By combining the polygonal lines of each groove 31 with the initial radome 30 drawing, the radome 30 drawing with the folded fan structure can be constructed.

[0050] Based on the above data, a model of radome 30 was created and imported into HFSS for simulation. The optimization effect of radome 30 on antenna 21 performance was verified. Based on the radiation patterns of the six antennas 21 in the HFSS simulation results, the X-coordinates of A, B, C, and D were continuously adjusted to ensure that the gain of antenna 21 within ±80 degrees met the design target (gain greater than 0dB at all angles ±θmax). This confirmed the final positions of A, B, C, and D, i.e., the final structural dimensions of radome 30. The final coordinates of A, B, C, and D in this design are: A (-21.6,2.32), B (-11.6,2.32), C (1.4,2.32), D (15,2.32).

[0051] In summary, this invention changes the angle of incidence of electromagnetic waves on different medium surfaces by altering the shape of the radome 30, thereby changing the angle after penetrating the radome 30. This is also an important principle behind the improved gain at large angles in this design. The optimized design of the radome 30 structure in this solution improves the gain of the antenna 21 at large angles, enhancing the radar's ability to identify obstacles at large angles.

[0052] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0053] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0054] Throughout this specification, the terms "an embodiment," "embodiment," or "specific embodiment" refer to a particular feature, structure, or characteristic described in connection with an embodiment that is included in at least one embodiment of the invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the invention.

[0055] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0056] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0057] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0058] The above description of the embodiments shown in this invention (including the content set forth in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the invention to the precise forms disclosed herein. Although specific embodiments and examples of the invention have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the invention, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the invention in accordance with the above description of the embodiments described herein, and such modifications will be within the spirit and scope of the invention.

[0059] This document has generally described the systems and methods in detail to aid in understanding the invention. Furthermore, various specific details have been set forth to provide a general understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention can be practiced without one or more specific details, or using other means, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0060] Therefore, although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the scope of the foregoing disclosure, and it should be understood that in some cases, certain features of the invention may be adopted without departing from the scope and spirit of the invention and without corresponding use of other features. Thus, many modifications can be made to adapt a particular environment or material to the essential scope and spirit of the invention. The invention is not intended to be limited to the specific terminology used in the following claims and / or the specific embodiments disclosed as the best mode for carrying out the invention, but the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the invention will be defined only by the appended claims.

Claims

1. A method for designing an antenna radome, characterized in that, Includes the following steps: Obtain antenna parameters; Based on the antenna parameters, determine the initial position of the recessed point of each groove on the radome in the first direction, such that the initial position of any one of the recessed points in the first direction is located between the boundary lines of the radiation angles of two of the antennas. The recessed point is the point on the inner side of the groove that is closest to the PCB board where the antenna is located. The first direction is a direction that is perpendicular to the length direction of the antenna and parallel to the PCB board. The cross-sectional profile of the groove is determined based on the preset position of the recessed point in the second direction, the angle between the two side walls of the groove and the normal of the PCB board, and the thickness of the radome. The second direction is the normal of the PCB board. Based on the initial position of the recessed point in the first direction and the cross-sectional profile of the groove, a three-dimensional model of the radome is established. The three-dimensional model of the radome is simulated, and the position of the recessed point in the first direction is adjusted until the gain of each antenna in any direction within the radiation angle range meets the preset requirements in the simulation results. The position of the recessed point at this time is taken as the final position of the recessed point, and the radome design is completed.

2. The radome design method according to claim 1, characterized in that, It also includes the following steps: The two corners of the top edge of the antenna cover, which are parallel to the antenna, are rounded.

3. The radome design method according to claim 1, characterized in that, The step of determining the initial position of the recessed points of each groove on the radome in the first direction according to the antenna parameters, such that the initial position of any one of the recessed points in the first direction is located between the boundary lines of the radiation angles of two of the antennas, includes: Based on the number of antennas and their positional distribution in the first direction, determine the number of recessed points and their original coordinates in the first direction. Determine two strongly correlated antennas for the depression point, wherein the strongly correlated antennas are the two antennas whose radiation angle boundary line is closest to the depression point; Based on the boundary line of the maximum radiation angle of the two strongly correlated antennas, determine the range of coordinate values ​​of the indentation point in the first direction. Choose any value from the range of coordinates of the depression point in the first direction as the initial position of the depression point in the first direction.

4. The radome design method according to claim 3, characterized in that, The step of determining the two strongly correlated antennas at the indentation point includes: Based on the original coordinates of the depression point, determine the antenna pair associated with the depression point. The antenna pair associated with the depression point refers to the area where the depression point is located within the intersection of the radiation angles of the two antennas in the antenna pair. Select the antenna pair with the smallest radiation angle crossover range from each group of antenna pairs, and use the two antennas in this antenna pair as the strongly correlated antennas of the recessed point.

5. The radome design method according to claim 1, characterized in that, The step of determining the cross-sectional profile of the groove based on the preset position of the recessed point in the second direction, the angle between the two side walls of the groove and the normal of the PCB board, and the thickness of the radome includes: Based on the thickness of the radome and the angle between the two side walls of the groove and the normal of the PCB board, calculate the distance between the recessed point and the lowest point of the top surface of the groove in the second direction; The position of the lowest point of the top surface of the groove in the second direction is determined based on the distance between the recessed point and the lowest point of the top surface of the groove in the second direction, and the position of the recessed point in the second direction. The top surface outline of the groove is determined based on the position of the lowest point of the top surface of the groove in the second direction and the angle between the two side walls of the groove and the normal of the PCB board. The bottom contour line of the groove is determined based on the position of the recessed point in the second direction and the angle between the two side walls of the groove and the normal of the PCB board.

6. The radome design method according to claim 1, characterized in that, The steps of simulating the three-dimensional model of the radome and adjusting the position of the recessed point in the first direction until the gain of each antenna in any direction within the radiation angle range meets the preset requirements in the simulation results include: The three-dimensional model of the radome is simulated, and the position of the recessed point in the first direction is adjusted until the gain of each antenna in any direction within the radiation angle range is greater than 0dB in the simulation results.

7. The radome design method according to claim 1, characterized in that, The angle between the two walls of the groove and the normal of the PCB board is 60°-80°.

8. The radome design method according to claim 1, characterized in that, The thickness of the radome is uniform at all locations, and the thickness of the radome is an integer multiple of half the wavelength of the electromagnetic wave signal transmitted or received by the antenna when it propagates within the radome material.

9. A millimeter-wave radar, characterized in that, include: Base; A PCB board is mounted on the base, and multiple antennas are formed on the PCB board, with each antenna arranged side by side at intervals. An antenna radome, which is connected to the base, covers the outer side of the PCB board; The radome includes a flat plate portion parallel to the PCB board and a groove formed in the flat plate portion. The groove is strip-shaped, and the length direction of the groove is parallel to the length direction of the antenna. The groove is set at the boundary of the radiation angle of the antenna.

10. The millimeter-wave radar according to claim 9, characterized in that, The groove is provided in multiple places, and each groove corresponds to the boundary setting of the radiation angle of the two antennas.

11. The millimeter-wave radar according to claim 9, characterized in that, The radome has rounded corners at its edges that are parallel to the length direction of the antenna.

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