Radar side shields and radar transceiver assemblies

Abstract

The present invention discloses a side shield (310) for a radar transceiver (130), the side shield (310) comprising a non-uniform delay structure arranged above an extension plane of the side shield, the non-uniform delay structure being configured to delay a radar signal (220, 320) propagating through the side shield (310) by a variable amount depending on the wavelength of the radar signal and depending on the position on the extension plane, thereby deflecting and / or diffusing the radar signal (320) after propagating through the side shield (310).

Description

Summary of the invention

[0001] The present disclosure relates to radar transceivers, and in particular to the installation of radar transceivers in vehicles.

[0002] A radar transceiver is a device arranged for transmitting and receiving radar signals in the radar frequency band. Radar transceivers are often used in vehicles for monitoring the vehicle surroundings. Automatic cruise control (ACC) functionality, emergency braking (EB) functionality, advanced driver assistance systems (ADAS) and autonomous driving (AD) are some examples of applications in which radar data represent an important source of information on which vehicle control can be based.

[0003] Vehicle radar transceivers are often arranged to be hidden behind vehicle body parts, such as the front or rear vehicle bumpers. This placement is often chosen for aesthetic reasons, but there is also a need to protect the radar transceiver from mechanical shock, moisture and dirt.

[0004] A disadvantage associated with hiding the transceiver behind a body part is that the radar transmission must penetrate the body part in order to monitor the vehicle surroundings. Some radar energy is typically reflected from the body part back into the cavity behind the body part. This reflected radar energy can appear as a false target and thus cause false radar target detections.

[0005] Some work has been done to improve the situation;

[0006] CN 108016388 discloses a vehicle bumper including a layered structure configured to reduce reflections.

[0007] DE 10 2010 028 185 relates to a vehicle body part suitable for use with a radar transceiver.

[0008] Another issue with radar systems in vehicle applications is the overall system cost. It is desirable to reduce the overall vehicle cost, which means that the cost of the radar system and its installation on the vehicle should be kept to a minimum.

[0009] The object of the present disclosure is to provide an improved radar transceiver assembly and installation technology. This object is achieved by a side shield for a radar transceiver. The side shield includes a non-uniform delay structure arranged above the side shield, and the non-uniform delay structure is configured to delay the radar signal propagating through the side shield by a variable amount according to the wavelength of the radar signal and according to the position on the surface of the side shield through which the radar signal propagates, thereby turning and / or diffusing the radar signal after propagating through the side shield. Therefore, any focused radar signal energy propagating through the side shield is defocused by phase randomization. This alleviates the problem of false detection caused by reflections in body parts.

[0010] According to various aspects, the non-uniform delay structure has a variable thickness measured along a normal vector to a surface of the side shield and / or a non-uniform dielectric constant measured along the normal vector.Therefore, the side shield can be cost-effectively manufactured by, for example, molding.

[0011] Also disclosed herein are a radar transceiver, an assembly method, and a vehicle associated with the above advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure will now be described in more detail with reference to the accompanying drawings, in which:

[0013] Figure 1 A schematic top view of a vehicle is shown;

[0014] Figure 2 Radar reflections through body parts are shown;

[0015] Figure 3 Radar reflection using radar side shield is shown;

[0016] Figure 4 Radar propagation through different media is shown.

[0017] 5 to 10 illustrate example radar side shields;

[0018] Figure 11 to Figure 12 An example radar transceiver assembly is shown; and

[0019] Fig.13 is a flow chart showing a manufacturing method. DETAILED DESCRIPTION

[0020] The inventive concept will now be described more fully below with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. However, the inventive concept can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that the disclosure will be thorough and complete and will fully convey the scope of the inventive concept to those skilled in the art. Throughout the specification, like numbers refer to like elements. Any steps or features shown by dotted lines should be considered optional.

[0021] Figure 1 A vehicle 100 is shown equipped with a vehicle radar system 110. The system 110 comprises a control unit 120 and at least one radar transceiver 130.

[0022] The control unit 120 and the radar transceiver 130 may be comprised in a single physical unit, or they may be distributed over more than one physical unit.

[0023] According to one example, vehicle radar transceiver 130 is arranged to generate and transmit radar signals in the form of frequency modulated continuous wave (FMCW) signals (sometimes also referred to as radar chirp signals), and receive reflected radar signals 125 , wherein the transmitted signals have been reflected by object 145 .

[0024] The present disclosure is not limited to FMCW radar waveforms. Instead, the disclosed concepts and techniques can be applied to many different radar waveforms. Specifically, the techniques disclosed herein are applicable to Orthogonal Frequency Division Multiplexing (OFDM) radars, and to Pulse Modulated Continuous Wave (PMCW) radars. An example of an OFDM radar is the stepped OFDM radar waveform described in EP3323151 A1.

[0025] The radar transceiver 130 is associated with a field of view 140. In the case where the radar transceiver is a front radar, the boresight direction 141 of the radar generally coincides with the centerline of the field of view, wherein the boresight direction 141 here also coincides with the heading direction F of the vehicle 100. In the case where the vehicle radar is alternatively configured as a side radar or a rear-facing radar, the boresight direction may be directed at some other angle compared to the heading direction F of the vehicle 100.

[0026] The radar transceiver 130 is mounted behind a body part of the vehicle 100. The body part may be, for example, a front bumper 150 or a rear bumper 160. Reflections in body parts arranged in front of the radar transceiver may produce an increased noise floor and false detections which are of course undesirable. Figure 1 One such false detection 170 is indicated in FIG. 1 . The radar sensor and / or control unit 120 cannot easily distinguish a false detection 170 from a real target 145. There may be multiple false targets 170 complicating radar signal processing.

[0027] Reflections in body parts, such as bumpers 150, 160, can produce unwanted radar sidelobes. Even though vehicle radars typically have a narrow elevation beamwidth, the effect of reflections in body parts can result in sidelobes at non-zero elevation (or azimuth), such as pointing more toward the ground. These sidelobes can contribute to increased clutter levels, which is undesirable.

[0028] Figure 2One cause for a false detection is schematically illustrated. Here, a radar transceiver 130 is arranged behind a bumper 150, which reflects a portion of the transmitted radar energy 220 back into a cavity behind the bumper 150. The reflected radar energy is incident on a certain reflective surface 210 on the vehicle 100, which returns the incident reflection. This return may at least partially end up back at the radar transceiver 130. As a result, the radar transceiver receives signal energy that appears to have reflected off a target, but this is actually a false detection 170. The reflected energy may reach the radar transceiver via a single reflection or via multiple reflections in more than one vehicle part.

[0029] In order to reduce the problem of false radar detection 170, it is proposed herein to arrange a side shield near the radar transceiver 130. The side shield is configured to randomize the phase distribution of electromagnetic waves propagating through the shield.

[0030] If the radar signal has been focused to a narrow side lobe (somewhat similar to a satellite antenna effect) by the shape of a body part (such as a bumper), the transmitted power density can be increased, for example, 10 dB higher than if the body part is flat. When this focused beam hits the side shield, if the shield is flat, the phase wavefront will appear on the far side of the side shield medium substantially parallel to when it arrived, so the focused beam will continue to remain focused. However, if the phase wavefront of the radar signal 220 is randomized by propagating through the phase randomized side shield, then after the side shield is penetrated, the beam is no longer focused and the energy density (in power per solid angle) is reduced. In other words, by randomizing the phase distribution of the radar signal, the radar signal is diverted or diffused by the side shield. This of course occurs in both the transmit and receive directions. Randomizing the phase distribution here means that the phase wavefront across the two-dimensional outer surface of the radar side shield has become randomized, for example, which removes any focusing effect that has been achieved by body parts such as bumpers.

[0031] Figure 3 An example of a radar transceiver assembly 300 including this type of phase randomized side shield 310 is shown. The radar side shield 310 is typically arranged transversely with respect to the transmission direction of the radar transceiver 130, i.e., extends from the side of the transceiver housing, such as Figure 3 The radar side shield extends in an extension plane, such as extending laterally from the radar transceiver. However, the side shield surface may be planar or curved.

[0032] The side shields 310 discussed herein all include a non-uniform delay structure arranged above the extension plane of the side shield. The non-uniform delay structure is configured to delay the radar signal 220, 320 propagating through the side shield 310 by a variable amount depending on the wavelength of the radar signal and depending on the position on the side shield through which the radar signal propagates. This means that the structure is non-uniform in the sense that the phase of the signal component leaving the side shield 310 depends on the spatial position where the signal component interacts with the side shield. The effect of the side shield is to randomize the phase distribution of the radar signal 320 after propagation through the side shield 310 as described above.

[0033] According to some aspects, the randomized phase distribution is a uniform phase distribution within some angular range, such as 0 to π or 0 to 2π.

[0034] The side shield can be configured with a non-uniform delay structure to generate phase randomization in a number of different ways. For example, according to some aspects, the non-uniform delay structure has a non-uniform (variable) thickness measured along the normal vector V to the extension plane.

[0035] In general, the wavelength of a transmitted radar signal in a vacuum (denoted as λ0) changes to when the radar signal propagates through a material having a dielectric constant ε different from the permittivity ε0 of a vacuum. This effect causes a phase shift in the radar signal when propagating through a material, compared to the same radar signal propagating the same distance through a vacuum. For example, if a radar signal with a wavelength λ0 in vacuum propagates through a material with thickness x and dielectric constant ε, the phase shift of the signal due to propagation through the material is approximately

[0036] The signal velocity is the speed at which waves travel. The signal velocity is usually equal to the group velocity (the velocity of a short "pulse" or the middle or "envelope" of a wave packet). However, in a few special cases (e.g., a medium designed to amplify the frontmost part of a pulse and then attenuate the back of the pulse), the group velocity can exceed the speed of light in a vacuum, while the signal velocity will still be less than or equal to the speed of light in a vacuum.

[0037] In the transmission medium, the signal speed v s It is the reciprocal of the square root of the product of capacitance and inductance, where inductance and capacitance are usually expressed per unit length;

[0038]

[0039] where ε r is the relative permittivity of the medium, μ ris the relative permeability of the medium, and c is the speed of light in a vacuum. The approximation shown is used in many practical contexts because for the most common materials, μ r ≈1.

[0040] refer to Figure 4 , consider two components 220A, 220B of a radar signal propagating at a normal angle of incidence. The first component 220A has a first dielectric constant ε A The second component 220B also propagates the first distance x in the air with a first dielectric constant ε. A and then propagates a third distance H corresponding to the first propagation of the first dielectric constant ε B The height H of the protrusion 410 made of a dielectric material of . The protrusion 410 is made of a plastic material, for example. According to some aspects, the second dielectric constant ε B Between 2 and 3, for example about 2.6.

[0041] Since the first component 220A propagates only the first distance x in the air, and the second component 220B propagates the first distance x partially in the air and partially through the protruding portion 410, the first component 220A and the second component 220B will have different respective relative phases from each other after having propagated the first distance x.

[0042] These relative phases of the two components 220A, 220B for:

[0043]

[0044] In order to approximate the range from 0 to π relative to Randomization The height H is preferably between 0 mm and For an automotive radar operating at about 77 GHz, where the wavelength λ0 in air is about 4 mm, then the maximum height H is estimated to be about 3 mm.

[0045] Light rays with incident angles other than the normal angle will of course have a larger phase difference because the effective distance through the plastic cuboid-shaped protruding element will be longer.

[0046] One example of a side shield 310 having a non-uniform thickness is a side shield that includes a carrier structure 315 that tapers in a certain direction, for example, as Figure 5A, which tapers from a thickness of z mm to a thickness of H+z mm. The radar signal component exiting the side shield then has a phase according to where it penetrates the side shield as the thickness varies on the side shield. The radar signal component penetrating the side shield at the thickest end propagates through a material thickness of about H+z mm, while the radar signal component propagating through the thinnest end only experiences a side shield thickness of about z mm. The wedge-shaped side shield also bends the signal 320 to the left, i.e., the exiting radar signal 320 is not parallel to the incoming signal 220 due to the diffraction effects through the side shield. This is a beneficial effect of the wedge, if the side shield is known to be present, the energy is deflected away from the reflecting surface.

[0047] Figure 5B An example of a conical radar side shield is shown that also includes an uneven surface 520 to further randomize the phase of radar signals propagating through the side shield.

[0048] Another example of a side shield having a non-uniform delay structure is a side shield including a carrier structure 315 and a plurality of protrusions. Figures 6 to 8 and Fig.12 Examples of different types of protrusions 610, 710, 810, 1210 are schematically shown in FIG. Each protrusion is configured to delay the radar signal 220, 320 propagating through the side shield 310 by a corresponding amount depending on the wavelength of the radar signal. Due to the variable delay amount, the radar signal will include components with different phases after propagating through the side shield. In other words, patterning the side shield rather than using a typical flat surface has the effect of randomizing the phase wavefront that propagates beyond the side shield. This phase randomization diffuses the radar signal.

[0049] For example, adding cones or other protrusions to the inner and / or outer surfaces of the side shield 310 will randomize the phase of the signal appearing on the outer surface, thereby widening and reducing the strength of any side lobes.

[0050] refer to Figures 6 to 8 In the example shown in FIG. 1 , the plurality of protrusions 610, 710, 810 are configured to randomize the phase distribution of the radar signal 320 after propagating through the side shield 310. This can be achieved, for example, by configuring the protrusions to have different shapes and / or to have materials having different dielectric constants. For example, at least one of the protrusions can be formed as a pyramid-shaped protrusion 610, Figure 6 The pyramid-shaped protrusion 610 will cause the radar signal to experience different propagation delays depending on where the radar signal propagates through the side shield. The protrusion can also be formed into other shapes, such as Figure 7 The rectangular protrusion 710 is illustrated in FIG.

[0051] Figure 8 Pyramidal protrusions 810 are shown on both sides of the carrier structure 315. The height of the pyramidal protrusion 810 on each side is H / 2, so that the total height of the pyramidal protrusion 810 is H.

[0052] This applies to all types of protrusions, and according to some aspects, the protrusions 610, 710, 810 can be arranged on one or both sides of the side shield, that is, they can be arranged on a first side of the side shield and / or on a second side of the side shield opposite to the first side.

[0053] The protrusions may also be formed as polygonal protrusions. Blends of different shapes may be used to generate the desired phase randomization effect.

[0054] According to some aspects, such as Figures 6 to 8 As shown, the projections 610, 710, 810 are supported by the carrier structure 315. However, as Figures 6 to 8 The support structure 315 is shown in dashed lines in FIG. 3 , which is optional. If the protrusions 610 , 710 , 810 form a self-supporting cohesive material piece, a support structure is not necessary.

[0055] If a carrier structure 315 is used, such a carrier structure may have a dielectric constant that is the same as or different from the dielectric constant of the protruding portions 610, 710, 810. The carrier structure 315 may also have any suitable shape, such as a cone, such as Figure 5A shown.

[0056] According to some aspects, combinations of different types of protrusions 610, 710, 810 can be used.

[0057] According to some aspects, the protrusions 610, 710, 810 are associated with a height in the range of 0 to H mm measured from the carrier structure 315 in the direction of extension of the protrusion. The height H can be determined based on the radar transmission wavelength λ0 in a vacuum and the dielectric constant ε of the material in the protrusion. For example, the height range of 0 to H mm can be determined as This gives a phase distribution of 0 radians to π radians. The height range can also be extended to include heights in the range of 0 to H'mm, where This gives a phase distribution of 0 radians to 2π radians.A range of heights may also be chosen somewhere in between to generate a phase randomization.

[0058] At least some of the side shields disclosed herein may be cost effectively manufactured by integrally forming the protruding portion and the carrier structure in a plastic material. That is, the radar side shield 310 may be formed in a single piece by molding a plastic material, which is an advantage.

[0059] Plastic materials can consist of a broad range of any synthetic or semi-synthetic organic compounds that are ductile and can therefore be molded into solid objects. Plasticity is a general property of all materials that can be irreversibly deformed without breaking, but in the class of moldable polymers this occurs to such an extent that its actual name is derived from this specific ability. Plastics are usually high molecular weight organic polymers and often contain other substances. They are usually synthetic, most commonly derived from petrochemicals.

[0060] Alternatively, or in addition to molding the side shield in a single piece, the protruding portions 610, 710, 810 may be attached to the carrier portion 315 by any of: an adhesive layer, a snap fit mechanism, an interference fit mechanism, and / or by ultrasonic welding.

[0061] Thermoplastic olefin (TPO) or other plastics are the preferred materials for making radar side shields. Radar absorbing plastics are available, however, the properties may vary, they are more expensive, and may be more complicated to mold and weld.

[0062] Phase randomization of radar signals propagating through the side shields may also be achieved by adding blocks of material to the carrier structure 315, wherein the added material has a different dielectric constant compared to the dielectric constant of the carrier structure material.

[0063] Fig. 9 One such example radar side shield is shown in which the non-uniform delay structure has a non-uniform dielectric constant along the normal vector V. This means that the dielectric constant experienced by the electromagnetic signal components propagating through the side shield is different at different locations above the side shield 310. The embedded portion 910 is associated with a dielectric constant ε that is different from the dielectric constant of the carrier structure 315. The embedded portion 910 is preferably formed to have different shapes to cause the phase randomization described above. It is also possible to add embedded portions that have been formed in different materials with different dielectric constants. According to some aspects, the non-uniform delay structure has a non-uniform dielectric constant along the normal vector V, but has a uniform thickness. Of course, it is conceivable that according to Fig. 9 The non-uniform delay structure also has a non-uniform thickness.

[0064] Fig. 10A and Fig. 10B Schematically shown are a side view and a top view of a radar side shield 310 in which irregular or piecewise linear grooves 1010 have been formed on the side shield surface. The grooves also have the effect of randomizing the phase distribution.

[0065] The side shield 310 may also be formed to have an irregular or jagged surface, such as Fig. 10C This is illustrated in the side view shown in FIG. Fig. 10C A side view of a radar side shield 310 having a sawtooth pattern on the inner and outer surfaces is shown. This has the advantage of a more constant material thickness for molding. Both the top and bottom surfaces of the side shield 310 are irregularly shaped in order to maintain a more constant material thickness for molding.

[0066] Fig.11 A radar transceiver assembly 1100 is schematically illustrated in which sawtooth-shaped grooves have been formed into a (generally flat) surface of a radar side shield 310 , which is shown here together with the radar transceiver 130 .

[0067] It may not be necessary to add a protrusion to the entire side shield. Therefore, according to some aspects, one or more protrusions 1210 are included in a portion of the surface of the carrier structure 315, such as Fig.12 , which shows an example radar transceiver assembly 1200 including the radar transceiver 130 and the side shield 310 according to the above discussion.

[0068] Fig.13 is a flow chart showing a method. Specifically, a method for manufacturing a side shield 310 for a radar transceiver 130 is shown. The method comprises: configuring S1 a mold for molding a plastic element, wherein the mold is configured to form one or more protrusions arranged to protrude from a carrier structure 315 of the side shield and / or irregular grooves in a surface of the side shield; and manufacturing S2 the side shield 310 by forming a plastic material through the mold.

[0069] The present disclosure is not limited to the above examples, but may also be freely varied within the scope of the appended claims.For example, according to some aspects, the radar transceiver 130 may be fully or partially surrounded by the radar side shield 310 , or positioned at an offset distance from the radar side shield 310 .

Claims

1. A side shield (310) for a radar transceiver (130), the side shield (310) comprising a non-uniform delay structure arranged above the side shield, the non-uniform delay structure being configured to delay the radar signal (220, 320) propagating through the side shield (310) by a variable amount depending on the wavelength of the radar signal and on the position on the side shield surface through which the radar signal (220, 320) propagates, thereby delaying the radar signal (220, 320) propagating through the side shield (310) by a variable amount. The radar signal (320) is then diverted and / or diffused, wherein the side shield (310) includes a carrier structure (315) and a plurality of protrusions (610, 710, 810, 1210), wherein each protrusion is configured to delay the radar signal (220, 320) propagating through the side shield (310) by a corresponding and variable amount depending on the wavelength of the radar signal, thereby randomizing the phase distribution of the radar signal (320) after propagating through the side shield (310).

2. The side shield (310) according to claim 1, wherein the non-uniform delay structure has a variable thickness measured along a normal vector (V) to the surface of the side shield and / or a non-uniform dielectric constant measured along the normal vector (V).

3. The side shield (310) of claim 1, wherein the randomized phase distribution is a uniform phase distribution.

4. The side shield (310) of claim 1, wherein the projection and the carrier structure are integrally formed in a plastic material.

5. The side shield (310) of claim 1, wherein the protruding portion (610, 710, 810, 1210) is attached to the carrier structure (315) by any one of: an adhesive layer, a snap fit mechanism, an interference fit mechanism, and / or by ultrasonic welding.

6. The side shield (310) according to claim 1, wherein the protruding portion (610, 710, 810, 1210) is associated with a height in the range of 0 to H mm measured from the carrier structure (315) in the extension direction of the protruding portion, wherein the height H is determined according to the radar transmission wavelength λ0 in a vacuum and the dielectric constant ε of the material in the protruding portion (610, 710, 810).

7. The side shield (310) according to claim 6, wherein the height H is determined as 8. The side shield (310) according to claim 6, wherein the height H is in the range of 2 mm-4 mm.

9. The side shield (310) according to claim 8, wherein the height H is 3 mm.

10. The side shield (310) according to any one of claims 1 to 6, wherein at least one of the protrusions is a pyramidal protrusion (610, 810, 1210), a cuboid protrusion (710), an irregular or piecewise linear groove or a polygonal protrusion.

11. The side shield (310) according to any one of claims 1 to 6, comprising one or more embedded parts (910), wherein the dielectric constant ε of the embedded parts (910) and the carrier structure (315) of the side shield (310) is 1.5-2.

0. c Different dielectric constants ε are associated.

12. The side shield (310) according to any one of claims 1 to 6, wherein the one or more protruding portions (1210) are included within a portion of a surface of the carrier structure (315).

13. A radar transceiver assembly (1100, 1200) comprising a radar transceiver (130) and a side shield (310) according to any preceding claim.

14. A vehicle (100) comprising the radar transceiver assembly (1100, 1200) according to claim 13.

15. A method for manufacturing a side shield (310) for a radar transceiver (130), the method comprising: configuring (S1) a mold for molding a plastic component, wherein the mold is configured to form one or more protrusions (610, 710, 810, 1210) arranged to protrude from a carrier structure (315) of the side shield and / or irregular grooves in a surface of the side shield (310); as well as The side shield (310) is manufactured (S2) by forming a plastic material through the mold, wherein each protrusion is configured to delay the radar signal (220, 320) propagating through the side shield (310) by a corresponding and variable amount according to a wavelength of the radar signal, thereby randomizing a phase distribution of the radar signal (320) after propagating through the side shield (310).

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