Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/88—Radar or analogous systems specially adapted for specific applications
  • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
  • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/27—Adaptation for use in or on movable bodies
  • H01Q1/32—Adaptation for use in or on road or rail vehicles
  • H01Q1/3208—Adaptation for use in or on road or rail vehicles characterised by the application wherein the antenna is used
  • H01Q1/3233—Adaptation for use in or on road or rail vehicles characterised by the application wherein the antenna is used particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
  • H01Q1/422—Housings not intimately mechanically associated with radiating elements, e.g. radome comprising two or more layers of dielectric material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/28—Combinations of substantially independent non-interacting antenna units or systems
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
  • G01S13/88—Radar or analogous systems specially adapted for specific applications
  • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
  • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
  • G01S2013/9327—Sensor installation details
  • G01S2013/93277—Sensor installation details in the lights
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
  • G01S7/027—Constructional details of housings, e.g. form, type, material or ruggedness

Definitions

• Vehicle assembly comprising a radar sensor and a set of layers
• the present invention relates to a vehicle assembly. It finds a particular but nonlimiting application in motor vehicles.
• a vehicle assembly comprises, in a manner known to those skilled in the art: a radar sensor configured to emit / receive radar waves, and
• a set of layers comprising at least two layers of dielectric material including a primary layer and a secondary layer, separated by an air layer.
• the vehicle assembly is disposed at the front or rear of the vehicle to meet the needs of detecting an object in the environment outside the vehicle.
• a drawback of this state of the art is that the radar sensor is placed behind the set of layers.
• the radar waves must thus pass through the layers of dielectric material to detect an object in the environment outside the vehicle. Some of these radar waves are reflected off the layers of dielectric material and between the layers of dielectric material inside the air layer. Consequently, the power of the radar waves emerging from the set of layers is lower than that of the radar waves initially emitted by the radar sensor and entering the set of layers. This thus results in a loss of detection range of the radar sensor. Therefore, it causes detection error or no detection of an object while the latter is present in the environment outside the vehicle.
• the present invention aims to provide a vehicle assembly which overcomes the mentioned drawback.
• the invention provides a vehicle assembly for a vehicle, said vehicle assembly comprising:
• a radar sensor configured to emit / receive radar waves, said radar sensor being arranged opposite a set of layers, and
• said set of layers comprising at least two layers of dielectric material including a primary layer and a secondary layer, separated by an air layer,
• said vehicle assembly may further include one or more additional characteristics taken alone or in any technically possible combination, among the following.
• said emerging reflected waves emerge from said primary layer on the side opposite to said radar sensor.
• said radar sensor is a millimeter wave (between 24 GHz and 300 GHz) or microwave (between 300 MHz and 81 GHz) or microwave (between 1 GHz and 300 GHz) radar sensor.
• said radar waves are transmitted over a frequency band between 100 MHz and 3GHz.
• said primary layer is a decorative piece and said secondary layer is an outlet glass of a lighting device of said vehicle.
• said lighting device is a headlight or a rear light.
• said primary layer is a luminous element of a logo and said secondary layer is an outlet glass of a logo of said vehicle.
• said primary layer is a radome and said secondary layer is a logo.
• said set of layers comprises more than two layers of dielectric material including primary layers and secondary layers, separated by an air layer.
• the angle of incidence Q3 is equal to the angle of incidence Q1.
• the angle of incidence Q3 is equal to the angle of incidence Q2.
• the angle of incidence Q2 is equal to the angle of incidence Q1.
• said set of layers comprises more than two layers of dielectric material including primary layers and secondary layers, separated by an air layer.
• FIG. 1 is a schematic view of a vehicle assembly, said vehicle assembly comprising a radar sensor and a set of layers with at least two layers of dielectric material including a primary layer and a secondary layer, separated by an air layer , according to a first non-limiting embodiment of the invention
• FIG. 2 is a schematic view of a propagation of a radar wave emitted by the radar sensor of said vehicle assembly of FIG. 1, and of its reflections on the two layers of dielectric material, according to a non-limiting embodiment
• FIG. 3 is a schematic view of a vehicle assembly, said vehicle assembly comprising a radar sensor and a set of layers with more than two layers of dielectric material including two primary layers and two secondary layers, each set of primary layer-layer secondary being separated by a layer of air, according to a second non-limiting embodiment of the invention.
• the vehicle assembly 1 of a vehicle 2 is described with reference to Figures 1 to 3.
• the vehicle 2 is a motor vehicle.
• motor vehicle is meant any type of motor vehicle. This embodiment is taken as a non-limiting example in the remainder of the description. In the remainder of the description, the vehicle 2 is thus otherwise called motor vehicle 2.
• the vehicle assembly 1, otherwise called the vehicle arrangement 1, comprises:
• a radar sensor 10 configured to transmit / receive RI radar waves
• a set of layers C otherwise called an arrangement of layers C, comprising at least two layers of dielectric material 11, 12 including a primary layer 11 and a secondary layer 12, separated by an air layer 13.
• the radar sensor 10 is placed opposite the primary layer 11.
• the radar sensor 10 is a millimeter wave (between 24 GHz and 300 GHz) or microwave (between 300 MHz and 81 GHz) radar sensor. ) or microwave (between 1GHz and 300GHz).
• the radar sensor 10 operates at a radar frequency of between 76 GHz and 81 GHz.
• the radar waves RI are transmitted over a frequency band between 100 MHz and 3GHz.
• the radar sensor 10 will operate on a frequency band of 76.5GHZ to 77.5GHz.
• the radar sensor 10 is configured to scan the external environment of the motor vehicle 2, thanks to the emission of radar waves RI. As illustrated in Figures 1 and 4, the radar sensor 10 thus comprises:
• At least one transmitting antenna 100 configured to transmit primary radar waves RI
• the radar sensor 10 further comprises at least one transmitter 103 configured to generate the primary radar waves RI and at least one receiver 104 configured to process the secondary radar waves R2 received in return.
• a single electronic component can be used for both transmission and reception functions. There will thus be one or more transmitter / receiver called “transceiver” in the English language.
• Said transmitter 103 generates primary radar waves RI which are subsequently transmitted by the transmitting antenna 100, which when they encounter an object 3 (here a pedestrian in the non-limiting example illustrated) in the external environment of the motor vehicle 2 are reflected on said object 3. The thus reflected radar waves are waves transmitted back to the radar sensor 10.
• the secondary radar waves R2 received by the receiving antennas 101. These are radar waves retransmitted in the direction of the radar sensor 10
• the primary radar waves RI and the secondary radar waves R2 are radio frequency waves.
• the radar sensor 10 comprises a plurality of transmitters 103 and a plurality of receivers.
• the transmitting antenna 100 is configured to transmit the primary radar waves RI generated by the transmitter 103.
• the receiving antennas 101 are configured to receive the secondary radar waves R2 and communicate them to receiver 104 which subsequently processes them. There is a phase shift between the secondary radar waves R2 received by the receiving antennas 101 which makes it possible to deduce therefrom the position of the object 3 relative to the motor vehicle 2, object 3 which is located in the external environment of the motor vehicle 2
• the antennas 100, 101 are patch antennas otherwise called in the English language “patch antenna” or slot antennas otherwise called in the English language “slot antenna”.
• the antennas 100, 101, the transmitter 103 and the receiver 104 are arranged on a printed circuit board 105.
• the printed circuit board is a rigid printed circuit board otherwise called PCBA ("Printed Circuit Board Assembly" in the English language or a flexible printed circuit board, otherwise called “Flexboard” in English language.
• the radar sensor 10 further comprises an electronic control unit 106 configured to control the transmitter 103 and the receiver 104.
• a radar sensor being known to those skilled in the art, it is not described in more detail here. .
• the primary layer 11 is a decorative piece, otherwise called a bezel, and the secondary layer 12 is an outlet glass of a lighting device 20 of said motor vehicle.
• the lighting device 20 is a headlight or a rear light of the vehicle 2.
• the primary layer 11 is a light element of an illuminated logo and the secondary layer 12 is an illuminated logo exit mirror. In a non-limiting example, said light element is a light guide.
• the primary layer 11 is a radome and the secondary layer 12 is an illuminated logo or not.
• the primary layer 11 is a radome and the secondary layer 12 is an output lens from a lighting device 20.
• the lighting device 20 is a projector or a projector. vehicle tail light 2.
• the primary layer 11 and the secondary layer 12 are made of a dielectric material.
• the dielectric material is plastic, glass or ceramic.
• the plastic is polycarbonate. It is recalled that a dielectric material is non-conductive and therefore allows the radar waves RI to pass, unlike a conductive material.
• the set of layers C comprises a single primary layer 11 and a single secondary layer 12, separated by an air layer 13.
• the primary layer 11 comprises a thickness el, otherwise called primary thickness el, and two surfaces VI and V 2 which represent transition surfaces from one medium to another, otherwise called diopters VI and V 2.
• diopter VI one passes from the air referenced 8 to the dielectric material of the primary layer 11.
• diopter V2 one passes from the dielectric material of the primary layer 11 to air 8.
• the primary layer 11 has a refractive index n1.
• the secondary layer 12 comprises a thickness e2, otherwise called secondary thickness e2, and two surfaces V3 and V4 which represent transition surfaces from one medium to another, otherwise called diopters V3 and V4.
• e2 the thickness of the secondary layer 12
• V3 and V4 which represent transition surfaces from one medium to another, otherwise called diopters V3 and V4.
• n2 the refractive index
• the air layer 13 comprises a thickness e3, otherwise called tertiary thickness e3.
• the air layer 13 has a refraction index n3 equal to 1.
• the radar wave RI When the radar wave RI is emitted, another part is reflected on the surfaces VI and V 2 which respectively creates reflected waves R11 and R12 called of order 1.
• the radar wave RI emitted is reflected on the one hand directly on the surface VI outside the primary layer 11 resulting in the reflected wave Rll, and on the other hand on the surface V2 inside the primary layer 11 resulting in the reflected wave R12.
• the reflected waves Rll and R12 otherwise called Rll waves and R12 waves, are reflected waves which are parasitic reflections which return to the radar sensor 10 and which decrease the signal-to-noise ratio of the radar sensor 10 since they return in the direction of the radar sensor 10.
• the transmitted radar wave RI arrives on the primary layer 11 with an angle of incidence Q1.
• the angle of incidence Q1 is different from 0 °
• the corresponding refracted angle referenced b ⁇ in FIG. 2 is also different from 0 °.
• the path d ⁇ traveled by the waves reflected in the primary layer 11 is equal to 2el / cos (pi).
• the phase shift Df ⁇ between the reflected waves Rll and R12 thus depends on the cosine of the refracted angle b ⁇ (and therefore on the cosine of the angle of incidence Q1) and on the thickness el of the primary layer 11.
• Df ⁇ (2p (h1d1- 2eltan (i) sin (01)) / ⁇ ) + n with l the wavelength of the transmitted radar wave RI, and with n3 ⁇ nl.
• the primary layer 11 comprises a thickness el such that the reflected waves Rll, R12 of order 1 corresponding to said radar wave RI transmitted either in phase opposition.
• Their phase shift Df ⁇ is therefore of p modulo 2p. It creates destructive interference.
• the reflected waves Rll and R12 have therefore been removed in the 1st order by causing them to cancel each other partially. they partially. They thus reduce the signal-to-noise ratio less.
• the R11 and R12 waves do not strictly cancel each other out, due to the necessarily lower amplitude of the R12 wave compared to the Rll wave. There is always a very weak residue of order 3. It is recalled that the reflected waves of order 2 have a lower power than the reflected waves of order 1, and the waves of order 3 have a lower power than the waves of order 3. 2nd order reflected waves.
• the thickness e1 is between 2 and 3 millimeters (mm).
• the radar wave RI when the radar wave RI leaves the primary layer 11, it is an emerging radar wave RI 'which has a lower power than the radar wave RI emitted.
• the emerging radar wave RI 'passes through the secondary layer 12 it is reflected on the surfaces V3 and V4 which respectively creates so-called order 1 reflected waves R13 and R14.
• the emerging radar wave RI ' is reflected on the one hand directly on the surface V3 outside the layer secondary 12 resulting in the reflected wave R13, and on the other hand on the surface V4 inside the secondary layer 12 resulting in the reflected wave R14.
• the reflected waves R13 and R14 are reflected waves which are parasitic reflections which return towards the radar sensor 10 and which decrease the signal to noise ratio of the radar sensor 10 since they return in the direction of the radar sensor 10. This also results in a loss of detection range of the radar sensor. Therefore, it causes detection error or no detection of an object while the latter is present in the environment outside the vehicle. As described below, they are suppressed so that the signal to noise ratio of the radar sensor 10 is not reduced.
• the emerging radar wave RI arrives on the secondary layer 12 with an angle of incidence Q2.
• the corresponding refracted angle referenced b2 in the figure is also different from 0 °.
• the path 52 traveled by the reflected waves R14 is equal to 2e2 / cos (P2).
• the phase shift Df2 between the reflected waves R13 and R14 thus depends on the cosine of the refracted angle b2 (and therefore on the cosine of the angle of incidence Q2) and on the thickness e2 of the secondary layer 12.
• Df2 (2n (n252-2e2tan (P2) sin (02)) / ⁇ ) + p.
• the secondary layer 12 comprises a thickness e2 such that the reflected waves R13, R14 of order 1 corresponding to said transmitted radar wave RI is in phase opposition. Their phase shift Df2 is therefore p modulo 2 p. It creates destructive interference. In the same way as the reflected waves R11 and R12, the reflected waves R13 and R14 partially cancel each other out. The reflected waves R13 and R14 have therefore been eliminated by making them partially cancel each other out. They thus reduce the signal to noise ratio less. It should be noted that the R13 and R14 waves do not strictly cancel each other out, due to the necessarily lower amplitude of the R14 wave compared to the R13 wave. There is always a very weak residue of order 3.
• the other part of the reflected waves R20 emerging from the primary layer 11 passing through the air layer 13 bounces alternately on the surface V 2 outside the primary layer 11 and on the surface V3 outside. of the secondary layer 12 and subsequently passes through the secondary layer 12 and emerges from the secondary layer 12. They arrive on the secondary layer 12 also with the angle of incidence 03.
• the reflected waves R16 of order 2 thus come from waves which are reflected inside the air layer 13 on a surface V 2 outside the primary layer 11 and which have crossed directly into a large mostly secondary layer 12.
• the path difference d3 traveled between the reflected waves R16 and the reflected waves R15 is equal to 2e3 / cos (03) -2e3tan (03) sin (03).
• the phase shift Df3 between the reflected waves R16 and R16 depends on thus of the cosine of the angle of incidence Q3 and of the thickness e3 of the air layer 13.
• Df3 4 px (e3 x cos (03)) / l.
• the reflected waves R15 and R16 are thus in phase.
• the phase shift of 0 modulo 2n makes it possible to add the reflected waves R15 and R16 to one another so that their power is added together and that there is thus a resulting reflected wave R17 of higher power.
• the thickness e3, in a non-limiting embodiment, has been preferably optimized for an angle other than 01. In production, the thickness e3 and the operating frequency of the radar may vary from their respective nominal values.
• the reflected wave R17 resulting from the addition of the reflected waves R15 and R16 will thus allow precise detection by the radar sensor 10. Indeed, its power will be added to that of the emerging radar wave RI. directly from the secondary layer 12, the choice of el ensuring that R15 and RI "are in phase.
• the reflected wave R17 and the radar wave RI "form an emerging global radar wave referenced R3 in FIG. 2 and otherwise called the global wave R3. Therefore the overall power obtained from the emerging global radar wave R3 of the secondary layer 12 (which will therefore be used to detect object 3) will be very close to that of the radar wave RI initially emitted by the radar sensor 10.
• the radar sensor 10 operates on a frequency band (between 100 MHz and 3 GHz in a non-limiting embodiment) and not on a single frequency.
• a frequency band between 100 MHz and 3 GHz in a non-limiting embodiment
• each thickness el, e2, e3 depends on the wavelength l, it is possible to define each thickness el, e2, e3, as a function of a wavelength l ⁇ , l2 , A3 different, the three wavelengths chosen being in the frequency band chosen between 100MHz and 3GHz here.
• a wavelength corresponding to the frequency 75 GHz is chosen to define the thickness el, a wavelength L2 corresponding to the frequency 77GHz to define the thickness e2, and a wavelength A3 corresponding to the frequency 76GHz to define the thickness e3.
• the detection of the radar sensor 10 is very precise because there will be no more parasitic reflections Rll, R12, R13, R14 and the radar waves R15, R16 will have been added to have very little power loss at the output of the set of layers C.
• each thickness e1, e2, e3 can be defined as a function of the same wavelength l.
• said set of layers C comprises more than two layers of dielectric material 11, 12 including primary layers 11 and secondary layers 12 separated by a air layer 13. There is thus a plurality of air layers 13.
• the vehicle assembly 1 comprises more than two layers of dielectric material 11, 12 separated by an air layer 13.
• a first subset of csl layers comprising a first primary layer 111 with a thickness ell and a first secondary layer 121 with a thickness e21, separated by an air layer 131,
• a second subset of layers cs2 comprising a second primary layer 112 with a thickness el2 and a second secondary layer 122 with a thickness e22, separated by an air layer 132.
• the first secondary layer 121 of the first sub-assembly cs1 is also the second primary layer 112 of the second sub-assembly cs2.
• the first subset of csl layers comprises a first primary layer 111 which is a radome of the radar sensor 10 and a first secondary layer 121 which is a decorative piece, separated by a first layer air 131; and the second subset of layers cs2 comprises a second primary layer 112 which is said decorative piece and a second secondary layer 122 which is an outlet glass of a lighting device 20 of the motor vehicle 2, separated by a second layer of air 132.
• the first subset of csl layers comprises a first primary layer 111 which is a radome of the radar sensor 10 and a first secondary layer 121 which is a luminous element, separated by a first air layer 131; and the second subset of layers cs2 comprises a second primary layer 112 which is said luminous element and a second secondary layer 122 which is an output glass of a luminous device 20 of the motor vehicle 2, separated by a second layer of air 132.
• the vehicle assembly 1 can further comprise a radome separated from a decorative piece by a layer of air 13, said decorative piece 11 itself being separated from an outlet window by a layer. air 13.
• the decorative piece can be replaced by a light element. Note that the more layers there are in the set of layers C, the more the anti-reflection bandpass filter can be increased with the different thicknesses of the different layers by choosing different wavelengths l for the different thicknesses in a mode. non-limiting implementation.
• said set of layers C comprises more than two dielectric layers including primary layers 111, 112 and secondary layers 121, 122, separated by an air layer 131, 132 two by two. Namely a first primary layer 111 is separated from a first secondary layer 121 by a first air layer 131 and a second primary layer 112 is separated from a second secondary layer 122 by a second air layer 132.
• a layer 111 which is a radome and which has a thickness ell
• a layer 121 which is a decorative piece and which has a thickness e21
• an additional layer 122 which is an output lens from a lighting device and which has a thickness e22.
• Layer 111 is separated from layer 121 by an air layer 131 of thickness e31.
• Layer 122 is separated from layer 121 by an air layer 132 of thickness e32.
• layer 111 represents a primary layer as described above and layer 121 represents a secondary layer as described above.
• layer 121 represents a secondary layer also referenced 112 as described above and layer 122 represents a secondary layer such as previously described.
• the description of the invention is not limited to the embodiments described above and to the field described above.
• the radar sensor 10 comprises more than one transmitting antenna 100 and more than two receiving antennas 101.

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• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• General Physics & Mathematics (AREA)
• Computer Security & Cryptography (AREA)
• Electromagnetism (AREA)
• Radar Systems Or Details Thereof (AREA)
• Details Of Aerials (AREA)

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• 2020
  • 2020-06-09 FR FR2006005A patent/FR3111197B1/fr active Active
• 2021
  • 2021-06-01 EP EP21728933.9A patent/EP4162295A1/de active Pending
  • 2021-06-01 JP JP2022575835A patent/JP7494326B2/ja active Active
  • 2021-06-01 US US18/000,764 patent/US20230243961A1/en active Pending
  • 2021-06-01 WO PCT/EP2021/064617 patent/WO2021249817A1/fr unknown
  • 2021-06-01 CN CN202180041071.4A patent/CN115698763A/zh active Pending

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