Compact, broadband, waveguide-to-monolithic microwave integrated circuit upward vertical conversion with dimensional tolerance

Abstract

In one embodiment, a radar sensor includes a waveguide interface configured to contact a waveguide, the waveguide interface including a first aperture at least partially vertically aligned with a second aperture in the waveguide; a radio frequency (RF) feed; a first wing, the first wing being coplanar with the RF feed and waveguide interface, and the first wing electrically connecting the RF feed and waveguide interface; and a first conductive layer connected to a ground potential, the first conductive layer including a third aperture at least partially aligned with the first aperture and the second aperture, and the first conductive layer including a second wing forming a portion of the third aperture.

Description

Technical Field

[0001] The present disclosure relates to radar sensors, and more particularly to waveguides and monolithic microwave integrated circuits (MMICs) for radar sensors. Background Art

[0002] The background description provided herein is for the purpose of generally presenting the context of the present disclosure. Within the scope described in this background art section, the work of the presently named inventors and aspects of the specification that are not otherwise identified as prior art at the time of filing the application are neither expressly nor implicitly admitted to be prior art relative to the present disclosure.

[0003] Known vehicles can determine their current location based on at least one sensor mounted on the vehicle. For example, a vehicle can include a Global Positioning System (GPS), from which the position of the vehicle can be inferred. Determining the position via GPS involves radio signals from space satellites. However, radio signals are not always readily available. For example, GPS signals can be very weak, such that a relatively long time span is used to evaluate the position based on the signal. Sometimes, the signal is too weak to determine the position. In other cases, there is no available signal, for example, in a completely or partially enclosed surrounding area, such as a road tunnel and a building, such as an underground garage. In the absence of a GPS signal, the position cannot be determined. For example, for autonomous driving applications, the accuracy of GPS may not always be sufficient.

[0004] Some vehicles can include radar and / or lidar (light detection and ranging) sensors. Measurements (which can be referred to as scans) from such sensors may not be sufficient to determine the position with a target reliability and accuracy. The same problem can also occur with one or more motion sensors mounted on the vehicle. Additionally, using radar sensors or other sensor technologies may involve significant processing resources, for example, due to determining radar detection points from raw sensor data. The raw sensor data can be given as sensor data samples having a radial distance component and a rate of change of distance (velocity in the radial distance direction). Such sensor data can be represented as Doppler sensor data.

[0005] There is a need to provide an upward vertical conversion with dimensional tolerances, compactness, broadband, and waveguide to monolithic microwave integrated circuit (MMIC) in a radar sensor. Summary of the Invention

[0006] Among the features, the radar sensor includes: a waveguide interface which is conductive, configured to contact a waveguide, and includes a first aperture that is at least partially perpendicularly aligned with a second aperture in the waveguide; a radio frequency (RF) feed which is conductive; a first wing that is coplanar with the RF feed and the waveguide interface and electrically connects the RF feed to the waveguide interface; a first conductive layer electrically connected to a ground potential, the first conductive layer including a third aperture that is at least partially aligned with the first aperture and the second aperture, and the first conductive layer including a second wing that forms a part of the third aperture, wherein the first wing extends from a line through the axis of the RF feed in a direction towards a first surface of the first aperture, and wherein the second wing: extends from the line towards a second surface of the first aperture that is opposite to the first surface; and further extends from the second surface towards the first surface beyond the closest side of the RF feed to the first surface.

[0007] In a further feature, the first wing and the second wing are asymmetric.

[0008] In a further feature, the first wing includes a tapered portion.

[0009] In a further feature, the tapered portion includes at least one bend.

[0010] In a further feature, the second wing includes a convex portion and a concave portion.

[0011] In a further feature, the second wing includes at least two bent portions.

[0012] In a further feature, the second wing includes a linear portion that extends between the second surface and the first surface to a point closer to the first surface than the closest side of the RF feed.

[0013] In a further feature, a substrate and a second conductive layer are disposed on a first surface of the substrate, wherein the RF feed, the first wing, and the waveguide interface directly contact the second conductive layer, and wherein the conductive layer contacts a second surface of the substrate that is opposite to the first surface.

[0014] In a further feature, a waveguide is included.

[0015] In a further feature, the waveguide includes a conductive material on an outer surface of the waveguide.

[0016] In a further feature, an electrically insulating material is disposed within the second aperture.

[0017] In a further feature, the waveguide interface is C-shaped and the RF feed extends into an opening in the C-shape.

[0018] In a further feature, the first aperture is within the C-shape.

[0019] In a further feature, a conductive via electrically connects the first conductive layer to a ground potential.

[0020] In a further feature, the third conductive layer is electrically connected to a ground potential, wherein a conductive via electrically connects the first conductive layer to the third conductive layer.

[0021] In a further feature, the third conductive layer includes a first conductive portion, a second conductive portion, and an electrically insulating portion that electrically isolates the first conductive portion from the second conductive portion.

[0022] In a further feature, the first conductive portion is disposed within the second conductive portion, and wherein a conductive via electrically connects the first conductive layer to the first conductive portion.

[0023] In a further feature, a second substrate is disposed between the first conductive layer and the third conductive layer.

[0024] In a further feature, a line passing through the axis of the RF feed is perpendicular to a second axis of the first aperture and the second aperture.

[0025] In a further feature, the first wing includes at least one linear portion and at least one curved portion.

[0026] Further applicable fields of the present disclosure will become apparent from the specific embodiments, claims, and drawings. The specific embodiments and specific examples are only for illustrative purposes and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present disclosure will be more fully understood through the specific embodiments and the accompanying drawings, wherein:

[0028] Figure 1 is a top view of an example vehicle including a radar sensor for sensing features external to the vehicle;

[0029] Figure 2 is a functional block diagram of an example radar sensor system of a vehicle;

[0030] Figure 3 is a front side perspective view of an example implementation of a portion of a radar sensor that includes a waveguide with an upward vertical transition to a monolithic microwave integrated circuit (MMIC);

[0031] Figure 4 includes Figure 3 a bottom side perspective view of an example portion;

[0032] Figure 5 includes Figure 3 a bottom perspective view of an example portion;

[0033] Figure 6 Including Figure 3 Side cross-sectional view of the exemplary portion;

[0034] Figure 7 Exemplary illustration including a radio frequency (RF) conductor, a wing, and a waveguide interface;

[0035] Figure 8 Exemplary illustration including a metal layer with a second wing;

[0036] Figure 9 Is an exemplary top view showing an RF feed, a wing, and a waveguide interface, where the waveguide interface vertically covers a second metal layer of an exemplary implementation including a second wing;

[0037] Figures 10 to 11 Is an exemplary graph of S11 versus frequency at different X-direction displacement amounts; and

[0038] Figures 12 to 14 Is an exemplary top view showing an RF feed, a wing, and a waveguide interface, where the waveguide interface vertically covers a second metal layer of an exemplary implementation including a second wing.

[0039] In the drawings, reference numerals may be reused to identify similar and / or identical elements. Detailed Description

[0040] Energy is transmitted horizontally through the RF conductor and then upward through the waveguide via the first wing and the second wing. The first wing transfers energy from the RF conductor to the waveguide. The waveguide includes a first aperture through which the energy is transmitted vertically.

[0041] The metal layer is vertically disposed below the layer including the RF conductor and the first wing. The metal layer includes a second aperture that is at least partially aligned with the first aperture. The second wing forms a part of the second aperture. The second wing is asymmetric with respect to the first wing. The first wing extends toward a first side of the first aperture and the second aperture. The second wing extends toward a second side of the first aperture and the second aperture that is opposite to the first side. The second wing further extends toward the first side beyond the closest portion of the RF conductor. The second wing can maintain impedance matching even in the presence of some misalignments during the manufacturing process.

[0042] Figure 1 Includes a top view of an exemplary vehicle 10. A radar sensor 12 is mounted on the left side of the front bumper of the vehicle 10. The radar sensor 12 includes a vertical field of view and a horizontal field of view indicated by 14. The radar sensor 12 is configured to scan the field of view around the vehicle. The position of an object within the field of view can be detected based on the scan.

[0043] Although an example where the radar sensor 12 is mounted at the left front bumper of the vehicle 10 is provided, the vehicle 10 may include one or more other radar sensors. This application is applicable to radar sensors located at other positions of the vehicle.

[0044] Figure 2 A functional block diagram of an example radar sensor system including the vehicle 10 is shown. The radio frequency (RF) power source 204 applies RF power to the RF feed of the radar sensor 12. The RF feed of the radar sensor 12 will be discussed further below. Another part of the radar sensor 12 is connected to the ground potential.

[0045] The RF power source 204 generates RF power from power (e.g., alternating current (AC) or direct current (DC)) received from another source, such as the battery 208 of the vehicle 10.

[0046] In the radar sensor 12, the RF feed converts between a microstrip printed circuit board (PCB) single-input monolithic microwave integrated circuit (MMIC) and a waveguide antenna. The radar sensor 12 may have an antipodal feed design including a substrate and metal layers above and below the substrate. The top layer may be connected to the RF feed and includes radiating wings that convert the z-plane electric field (e-field) to the x-plane to match the waveguide field. The bottom layer also includes wings that extend in the negative x-direction (opposite to the radiating wings) and are connected to the ground potential.

[0047] Manufacturing may include positioning the substrate on the bottom metal layer and positioning the top layer on the substrate. However, due to manufacturing tolerances, for example, the top metal layer and the bottom metal layer may not be aligned in the x-direction.

[0048] Figure 3 A front side perspective view of an example implementation of a portion of the radar sensor 12 is shown, which includes a waveguide to a monolithic microwave integrated circuit (MMIC) with an upward vertical conversion. Figure 4 Including Figure 3 A bottom side perspective view of an example portion. Figure 5 Including Figure 3 A bottom perspective view of an example portion. Figure 6 Including Figure 3 A side cross-sectional view of an example portion.

[0049] Referring to Figures 3 to 6 , a first substrate 304 is disposed between a first (e.g., top) metal layer 308 and a second (e.g., middle) metal layer 312. The first substrate 304 may be, for example, a PCB, a substrate including silicon, or another suitable substrate. The metal of the first layer 308 and the second layer 312 may be, for example, copper, aluminum, or another suitable conductive material.

[0050] The second substrate 316 is disposed between the second metal layer 312 and the third (e.g., bottom) metal layer 320. The second substrate 312 can be, for example, a PCB, a substrate including silicon, or another suitable substrate. The metal of the third metal layer 320 can be, for example, copper, aluminum, or another suitable conductive material.

[0051] The RF feed conductor 324 is disposed on the first surface of the first metal layer 308. The first surface is opposite to the second surface of the first metal layer 308 facing the first substrate 304. The RF feed conductor 324 is connected to the output terminal of the RF power source 204. The RF feed conductor 324 is connected to the waveguide interface 328 via the wing 332. The RF feed conductor 324, the waveguide interface 328, and the wing 332 are made of a conductive material (such as copper or aluminum) and can be a single piece. The waveguide interface 328 can generally be C-shaped, and the RF feed conductor 324 extends through the opening in the C-shape. The direction in which the wing 332 turns from the RF feed conductor 324 to the waveguide interface 328 will be referred to herein as the X direction, such as Figure 3 illustrated in. The Y direction is perpendicular to the X direction and the Z direction, and the Y direction extends in the same direction as the RF feed conductor 324. The Z direction is perpendicular to both the X direction and the Y direction. The positive value of each direction can be in Figure 3 the direction of the arrow illustrated in. The negative value of each direction can be in Figure 3 the opposite direction of the arrow illustrated in.

[0052] The waveguide 336 is located on the waveguide interface 328. The waveguide 336 can be made of a conductive material, such as aluminum, copper, or another suitable conductive material. In various implementations, the waveguide 336 can include a core, and the conductive material can be disposed (e.g., coated) on the outer surface of the waveguide 336 and cover its outer surface. The core can be made of, for example, plastic.

[0053] The waveguide 336 includes an aperture 340, which can be referred to as the waveguide output port. The axis of the aperture 340 can be aligned with the center of the opening of the C-shape of the waveguide interface 328. The origin (point 0) of the X, Y, and Z directions can be located at the center of the opening of the C-shape. The Z axis can be coaxial with the axis of the aperture 340. The aperture 340 can be, for example, rectangular or have another suitable shape. In various implementations, the corners of the aperture can be rounded, such as Figure 3 shown in the example of.

[0054] The waveguide 336 can also include a second aperture 342, which is fluidly connected to the aperture 340. The RF conductor 324 extends through the second aperture 342. The second aperture 342 prevents the RF conductor 324 and the wing 332 from directly contacting the waveguide 336. Instead, the C-shaped waveguide interface 328 directly contacts the waveguide 336.

[0055] In various implementations, an encapsulation material (such as a dielectric material) can cover a first surface of the first metal layer 308, the RF conductor 324, and the waveguide interface 328, and the waveguide 336, and fill the first aperture 340. In various implementations, the aperture 344 can be formed to pass through the encapsulation material to and through the second aperture 342. In various implementations, the first aperture 340 can be filled with air.

[0056] As Figure 4 shown, the third metal layer 320 can include a first metal layer portion 404 and a second metal layer portion 408. The third metal layer 320 can include a removal portion 412 that electrically isolates the first metal layer portion 404 from the second metal layer portion 408. When viewed toward the third metal layer 320, the removal portion 312 can enable the second substrate 316 to be visible between the first metal layer portion 404 and the second metal layer portion 408. The first metal layer portion 404 can be electrically connected to a ground potential. The second metal layer portion 408 can also be electrically connected to the ground potential.

[0057] As Figure 4 、 Figure 5 and Figure 6 illustrated, the conductive via 416 electrically connects the second metal layer portion 408 to the second metal layer 312. The conductive via 416 includes a conductive material such as aluminum, copper, or another suitable conductive material. The conductive via 416 extends through the second substrate 316 to directly contact the second metal layer 312 and the second metal layer portion 408. The conductive via 416 can be referred to as a fence.

[0058] Figure 3 、 Figure 5 and Figure 8 include an exemplary illustration of the second metal layer 312. Figure 7 include exemplary illustrations of the RF conductor 324, the fin 332, and the waveguide interface 328. As Figure 7 illustrated therein, the waveguide interface 332 includes an aperture 704 that is aligned (e.g., coaxially aligned) with the aperture 340 that passes through the waveguide 336. The fin 332 is at least partially disposed within the aperture 704.

[0059] The second metal layer 312 further includes an aperture 804 that is aligned (e.g., coaxially aligned) with the aperture 340 that passes through the waveguide 336 and the aperture 704. The second metal layer 312 includes a second fin 808 that extends in a direction (-X direction) opposite to that of the fin 332 (the fin 332 extends in the +X direction). The fin 332 and the second fin 808 are tapered, which provides a broadband frequency response. The shape of the fin 332 and the fin 808 and how the fin 332 vertically overlaps the second fin 808 control impedance matching.

[0060] The second wing 808 is asymmetric with respect to the wing 332. The second wing 808 may include at least one concave portion and at least one convex portion, such as Figure 8 illustrated therein. The second wing 808 may include a serpentine design that includes two or more bends in different directions, such as Figure 8 shown. Alternatively, the second wing 808 may be formed of linear portions, such as Figure 12 illustrated in the example of. In various implementations, the second wing 808 may include one or more linear portions and one or more bends in one or more different directions. Figure 13 and Figure 14 An example illustration including the second wing 808 is shown, where the second wing 808 includes at least one linear portion and at least one curved portion.

[0061] The shape and size of the second wing 808 provide impedance matching even in cases where there may be misalignment between the first metal layer 308 and the second metal layer 312 in the +X or -X directions (such as during manufacturing, although within the target tolerance).

[0062] As Figure 6 illustrated by 604 in, energy is transmitted inward from the RF feed 324 to the aperture 340. The energy is transmitted upward as shown by 608. The dielectric material within the aperture 340 reflects the electromagnetic wave downward. The waveguide 336 guides the energy upward toward one or more antennas of the radar sensor 12.

[0063] Figure 9 is an example top view illustrating the RF feed 324, the wing 332, and the waveguide interface 328, where the waveguide interface 328 vertically covers the second metal layer 312 including an example implementation of the second wing 808.

[0064] The centerline 904 of the RF feed 324 may be coaxial with the Y-direction axis. The RF feed 324 has a width in the X direction such that the first side 908 of the RF feed 324 is disposed in the -X direction relative to the second side 912 of the RF feed 324 that is opposite the first side.

[0065] The second wing 808 of the second metal layer 312 extends beyond the second side 912 of the RF feed 324 in the positive X direction, such as Figure 3 illustrated therein. The second wing 808 may extend beyond the second side 912 of the RF feed 324 in the positive X direction by a distance that is at least a predetermined manufacturing tolerance, such as 0.1 millimeter (mm) or another suitable distance, in the X direction.

[0066] Alternatively, the second wing 808 can be symmetric with the wing 332 and be its mirror image (e.g., flipped in the -X direction), with the only overlap being at the RF feed 324. However, even within manufacturing tolerances, impedance mismatches can occur due to manufacturing misalignment in the X direction. The asymmetry of the second wing 808 with respect to the wing 332 provides additional resistance for X-direction misalignment and improves impedance matching in the case of misalignment.

[0067] Figure 10 An example graph including S11 (reflection coefficient or matching) tolerances for an example, in which the second wing 808 is symmetric with the wing 332 and is a mirror image, with the only vertical overlap being at the RF feed 324. Different trace graphs show different misalignment distances in the X direction.

[0068] Figure 11 An example graph including S11 (reflection coefficient or matching) tolerances for an example, in which the second wing 808 is asymmetric with the wing 332 as described above and extends beyond the second side 912 of the RF feed 324 in the X direction. Different trace graphs show different misalignment distances in the X direction.

[0069] As can be seen by comparing Figure 11 with Figure 10 the design of the second wing 808 described herein reduces the degradation of S11 across the frequency range. Similar results also apply to the reduced insertion loss (S21).

[0070] The design of the second metal layer 312 as described herein provides a smoother electric field transition to the waveguide 336 even in the case where there may be misalignment in the X direction. This results in better performance across the target frequency range of the radar sensor 12.

[0071] The foregoing description is illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent after study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method can be executed in a different order (or concurrently) without altering the principles of the disclosure. Additionally, while each of the embodiments above is described as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and / or combined with the features of any one of the other embodiments even if not explicitly described in that combination. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more of the embodiments with respect to each other is still within the scope of the disclosure.

[0072] A variety of terms are used to describe the spatial and functional relationships between components (e.g., between modules, circuit elements, semiconductor layers, etc.), including "connected", "joined", "coupled", "adjacent", "next to", "on", "above", "below", and "disposed". Unless explicitly described as "direct", when the relationship between a first component and a second component is described in the above disclosure, the relationship can be a direct relationship where no other intermediate components exist between the first component and the second component, but it can also be an indirect relationship where one or more intermediate components (either spatially or functionally) exist between the first component and the second component. As used herein, the phrase "at least one of A, B, and C" shall be interpreted to mean a logical (A or B or C) using non-exclusive logic "or", and shall not be interpreted to mean "at least one of A, at least one of B, and at least one of C". The drawings may be drawn to scale.

[0073] In the drawings, the direction of an arrow as indicated by the arrowhead generally shows the direction of the information flow of interest in the illustration (such as data or instructions). For example, when component A and component B exchange various information, but the information transmitted from component A to component B is relevant to the illustration, the arrow can point from component A to component B. This one-way arrow does not mean that no other information is transmitted from component B to component A. In addition, for the information sent from component A to component B, component B can send a request for the information or receive an acknowledgement from component A.

Claims

1. A radar sensor, comprising: a waveguide interface, the waveguide interface being electrically conductive, the waveguide interface being configured to contact a waveguide, and the waveguide interface comprising a first aperture at least partially vertically aligned with a second aperture in the waveguide; A radio frequency (RF) feed, wherein the RF feed is conductive; a first wing, the first wing being coplanar with the RF feed and the waveguide interface, and the first wing electrically connecting the RF feed to the waveguide interface; a first conductive layer, the first conductive layer being electrically connected to a ground potential, the first conductive layer comprising a third aperture, the third aperture being at least partially aligned with the first aperture and the second aperture, and the first conductive layer comprising a second wing, the second wing forming a part of the third aperture, wherein the first wing extends from a line passing through the axis of the RF feed in a direction towards the first surface of the first aperture, and Wherein, the second wing: extending from the line toward a second surface of the first aperture opposite the first surface; and Extending from the second surface further toward the first surface beyond a proximal side of the RF feed to the first surface.

2. The radar sensor according to claim 1, characterized in that The first wing and the second wing are asymmetrical.

3. The radar sensor according to claim 1, characterized in that The first wing includes a tapered portion.

4. The radar sensor according to claim 3, characterized in that The tapered portion includes at least one bend.

5. The radar sensor according to claim 1, characterized in that: The second wing includes a convex portion and a concave portion.

6. The radar sensor according to claim 1, characterized in that The second wing includes at least two curved portions.

7. The radar sensor according to claim 1, characterized in that The second wing includes a linear portion extending between the second surface toward the first surface to a point closer to the first surface than the proximal side of the RF feed.

8. The radar sensor according to claim 1, further comprising a substrate and a second conductive layer, wherein the second conductive layer is disposed on the first surface of the substrate. in, The RF feed, the first wing, and the waveguide interface directly contact the second conductive layer, and The conductive layer contacts a second surface of the substrate opposite to the first surface.

9. The radar sensor of claim 1, further comprising the waveguide.

10. The radar sensor according to claim 9, characterized in that The waveguide includes a conductive material on an outer surface of the waveguide.

11. The radar sensor of claim 9, further comprising an electrically insulating material disposed within the second aperture.

12. The radar sensor according to claim 1, characterized in that The waveguide interface is C-shaped, and the RF feed extends into an opening in the C-shape.

13. The radar sensor according to claim 12, characterized in that The first aperture is within the C-shape.

14. The radar sensor of claim 1, further comprising a conductive via electrically connecting the first conductive layer to the ground potential.

15. The radar sensor of claim 14, further comprising a third conductive layer, the third conductive layer being electrically connected to the ground potential, in, The conductive via electrically connects the first conductive layer to the third conductive layer.

16. The radar sensor according to claim 15, characterized in that The third conductive layer includes a first conductive portion, a second conductive portion, and an electrically insulating portion that electrically isolates the first conductive portion from the second conductive portion.

17. The radar sensor according to claim 16, characterized in that The first conductive portion is disposed within the second conductive portion, and The conductive via electrically connects the first conductive layer to the first conductive portion. 18 . The radar sensor of claim 15 , further comprising a second substrate disposed between the first conductive layer and the third conductive layer.

19. The radar sensor according to claim 1, characterized in that: The line passing through the axis of the RF feed is perpendicular to second axes of the first and second apertures.

20. The radar sensor according to claim 1, characterized in that The second wing includes at least one linear portion and at least one curved portion.

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