WO2021260983A1 - Capteur radar et système de capteur radar - Google Patents

Capteur radar et système de capteur radar Download PDF

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Publication number
WO2021260983A1
WO2021260983A1 PCT/JP2021/002041 JP2021002041W WO2021260983A1 WO 2021260983 A1 WO2021260983 A1 WO 2021260983A1 JP 2021002041 W JP2021002041 W JP 2021002041W WO 2021260983 A1 WO2021260983 A1 WO 2021260983A1
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Prior art keywords
antenna
feeding
line
radar sensor
antennas
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PCT/JP2021/002041
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English (en)
Japanese (ja)
Inventor
英幸 永石
幸徳 赤峰
博史 篠田
浩司 黒田
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日立Astemo株式会社
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Priority to DE112021002448.5T priority Critical patent/DE112021002448T5/de
Publication of WO2021260983A1 publication Critical patent/WO2021260983A1/fr

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    • 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
    • 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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/42—Simultaneous measurement of distance and other co-ordinates
    • 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
    • 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
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G01S7/032—Constructional details for solid-state radar subsystems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/20—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/206—Microstrip transmission line antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/29—Combinations of different interacting antenna units for giving a desired directional characteristic
    • H01Q21/293—Combinations of different interacting antenna units for giving a desired directional characteristic one unit or more being an array of identical aerial elements

Definitions

  • the present invention relates to a radar sensor and an in-vehicle radar sensor system using the radar sensor.
  • Radar sensors that uses radio waves as a peripheral detection sensor for safe operation and safe operation of automobiles, railways, transportation equipment, etc.
  • Radar sensors emit high-frequency transmitted waves such as microwaves and millimeter waves, and detect the distance to the obstacle and the relative velocity by using the Doppler effect generated between the reflected wave and the reflected wave from the obstacle.
  • a plurality of radar sensors having different detection distances and detection angle ranges are used in order to cover the entire circumference of the automobile in order to support safe driving and realize automatic driving.
  • medium- and short-range radar sensors for peripheral monitoring are expected to have a wide horizontal direction so as to avoid contact with pedestrians, bicycles, etc.
  • the horizontal detection angle range is 150 ° or more (FOV (Field of View) ⁇ 150 °).
  • a thin planar antenna is generally adopted as the antenna of the medium- and short-range radar.
  • the frontal direction of the planar antenna is defined as an azimuth angle of 0 °
  • the detection angle of the antenna is represented by an azimuth angle formed by the direction of the object and the frontal direction as seen from the antenna.
  • Patent Document 1 discloses a microstrip antenna having a simple configuration and a variable radiation direction of a radio wave beam. Specifically, an antenna (non-feeding element) connectable to the ground electrode is arranged around the antenna (feeding element) connected to the microwave signal source. The connection of the antenna, which is a non-feeding element, to the ground electrode is turned ON / OFF by a switch, and either the grounded state or the floated state is selected. When the non-feeding element is in the grounded state, it does not function as a radiating element, while in the float state, radio waves are also emitted from the non-feeding element, and the radiation direction of the antenna can be switched by spatially synthesizing with the radio waves from the feeding element. ..
  • a narrow angle antenna and beamforming technology in which the antenna gain is improved in a specific direction have been proposed.
  • a non-detection region where a notch with deteriorated reception sensitivity is likely to occur within the detection angle range is likely to occur.
  • three or more transmission feeding antennas are required.
  • the half-value width of the antenna gain is narrowed by expanding the aperture area by a large number of antenna elements, it is not suitable for detection in a wide angle direction.
  • Patent Document 1 discloses that the radiation direction of a radio wave beam from an antenna can be changed by arranging a non-feeding element in the vicinity of the feeding element. If the sensitivity of the antenna in the wide angle direction can be increased by using the non-feeding element, the sensitivity of the antenna in the wide angle direction can be increased without increasing the input / output terminals of the RF circuit. Therefore, by using the input / output terminals for the MIMO configuration, it is possible to improve both the wide-angle directional gain and the angular resolution.
  • radio waves radiated by the antenna of Patent Document 1 are mainly assumed to be microwaves (1 GHz or more), millimeter waves are assumed to be used especially in an in-vehicle radar sensor.
  • Millimeter waves are radio waves of 30 to 300 GHz in which the length of one wavelength is on the order of millimeters (1 to 10 mm).
  • radio waves are radiated by putting a non-feeding element in a float state, but as the frequency of a high frequency signal becomes higher, the capacitance between terminals of a switch device in the millimeter wave band may be as large as pF (picofarad). Therefore, it is difficult to increase the impedance of the connection point.
  • the non-feeding element is not completely floated, but is weakly connected to the ground electrode. Therefore, in the antenna disclosed in Patent Document 1, the radiant power from the non-feeding element is reduced in millimeter waves, and it is considered difficult to realize the half-value width improvement as designed.
  • the control line connected to the feeding element or the non-feeding element is arranged so as to penetrate the ground electrode of the substrate, so that a parasitic capacitance is likely to be attached, and the frequency of the radiated radio wave is also high. Indeed, the influence on the radiation characteristics of the feeding element becomes large. Further, when the control line length is ⁇ / 2 ( ⁇ is the wavelength in the free space of the radio wave) or more, the control line itself becomes a radiation element and unnecessary radiation is likely to occur. This is also a point that requires countermeasures.
  • a typical example of the invention disclosed in the present application is as follows. It is a radar sensor having a circuit board, a conductor layer provided in the circuit board and having a GND pattern to which a reference potential is given, and a conductor pattern provided on the surface of the circuit board, and has a high frequency terminal for transmission and a plurality of. It has a high-frequency circuit including a high-frequency receiving terminal, a transmitting antenna connected to the high-frequency transmitting terminal, and a plurality of receiving antennas connected to a plurality of high-frequency receiving terminals, respectively. It is a standing wave excitation type antenna formed as a conductor pattern facing the GND pattern and having an antenna pattern in which a plurality of radiation elements are arranged along a feeding line.
  • the transmitting antenna is a feeding antenna and a feeding line of the feeding antenna.
  • the feeding antenna of the transmitting antenna is connected to the high frequency terminal for transmission, and the feeding antenna is connected to the GND pattern via the line.
  • the line Assuming that the wavelength of the radio wave radiated from the radiating element on the line is ⁇ g, the line has an electric length of ⁇ g / 2 or an integral multiple thereof.
  • a radar sensor having a transmitting antenna or a receiving antenna having an improved antenna gain over a non-arrayed radiating element in a wide angle direction. This makes it easy to improve both the wide-angle directional gain and the angular resolution of the radar sensor.
  • FIG. 1 is a configuration example of the radar sensor of the first embodiment.
  • the radar sensor 100 includes an antenna 101, a GND 102 to which a reference potential is given, a line 103, a switch 104, a switch control circuit 105, and an RF circuit (high frequency circuit) 106.
  • the antenna 101 and the line 103 are microstrip antennas and microstrip lines in which a dielectric (board) is sandwiched between two conductors.
  • the path connecting the antenna 101T 2 or the antenna 101T 3 and the GND 102 constituting the transmitting antenna 131 is switchable, and the switch unit 110 is composed of the line 103 and the switch 104.
  • the high-frequency signal used for sensing is generated by the RF circuit 106 , propagated from the transmission RF terminal of the RF circuit 106 to the antenna 101T 1 on the transmission Tx side, and radiated as a radio wave from the transmission antenna 131.
  • the radiated radio wave is reflected by the object to be sensed, received by the antennas 101R 1 to R 4 on the receiving Rx side, and input to the receiving RF terminal of the RF circuit 106.
  • a plurality of antennas on the receiving Rx side are required to specify the position of the object that reflected the radio wave, but the number of antennas is not limited to four.
  • Equation 1 the wavelength of the radio wave radiated by the antenna 101 in the free space is ⁇ and the wavelength on the transmission line is ⁇ g, there is a relationship (Equation 1) between ⁇ and ⁇ g. ⁇ r is the relative permittivity of the dielectric (board).
  • FIG. 2A shows a layout example of the standing wave excitation type antenna used for the antenna 101.
  • the radiating elements 121 are arranged for each feeding line ⁇ g, which is called a series fed type antenna.
  • the radiating element 121 has a length of ⁇ / 2 in the longitudinal direction (referred to as the feeding direction) of the feeding line 122, and the length in the direction perpendicular to the feeding direction (hereinafter referred to as the width) is adjusted by the arrangement position. ..
  • the width of the radiating element 121 and adjusting the conductance value of the radiating element the power distribution of the tailor distribution can be realized and the side lobe of the antenna radiation pattern can be suppressed.
  • the absolute value of the maximum antenna gain can be improved.
  • the radiating element 121 and the feeding line 122 are shown separately, but as will be described later, the radiating element 121 and the feeding line 122 are integrally formed as a conductor pattern of the same layer.
  • the standing wave excitation type antenna used for the radar sensor of this embodiment is not limited to the series fed type antenna, and a comb line antenna in which the radiation element 121 is arranged for each feeding line ⁇ g / 2 can also be used.
  • FIG. 2B The layout of the transmitting antenna 131 and the four receiving antennas 101R 1 to R 4 is shown in FIG. 2B.
  • the receiving antennas 101R 1 to R 4 are laid out with the antenna spacing d
  • the phase difference ⁇ between the adjacent receiving antennas is shown below with the azimuth angle ⁇ of the object and the antenna spacing d (Equation 2). ).
  • Equation 3) is derived by transforming (Equation 2).
  • the radar sensor obtains the azimuth angle ⁇ of the object from the phase difference ⁇ obtained by measuring the received signals of the plurality of receiving antennas 101R 1 to R 4 using the relational expression shown in (Equation 3). Can be calculated.
  • the antenna spacing can be arbitrarily designed according to the angle range to be detected, and if the detection angle range is -90 ° to 90 °, the antenna spacing d should be ⁇ / 2, which allows a unique angle to be obtained. ..
  • the radar sensor shown in FIG. 1 has one transmitting antenna, but by providing a plurality of transmitting antennas 131, a virtual antenna having a MIMO configuration described later can be configured.
  • a MIMO configuration it is desirable that the antenna spacing between the feeding antenna and the non-feeding antenna is ⁇ / 2, which is the same as the antenna spacing between the receiving antennas. Further, it is desirable that the distance between the plurality of transmitting antennas 131 is also an integral multiple of ⁇ / 2. This is because the antennas of the transmitting antennas can be easily arranged in an array, and the calculation for estimating the virtual antenna sequence in the MIMO configuration becomes easy.
  • FIG. 3 shows a schematic cross-sectional view of the radar sensor.
  • a plurality of conductor layers 301 are provided in the circuit board 300 of the radar sensor.
  • digital signals, analog signals, or power supplies are separated by a GND pattern to prevent crosstalk.
  • a plurality of conductor layers are arranged as the conductor layer 301, and a large-area GND pattern 301g is provided in a part of the conductor layer 301 in order to suppress the parasitic resistance value and the parasitic inductance value of the GND 102.
  • a conductor pattern 302 on which an antenna 101, a line 103, and other pads are formed is provided.
  • the switch 104 and the RF circuit 106 are mounted as semiconductor chips and connected to a predetermined conductor pattern 302 provided on the surface of the circuit board 300.
  • the GND pattern 301g provided on the conductor layer 301 is connected to the surface layer GND 302g on the substrate surface by the interlayer via 303a, and the ball bump of the switch 104 is connected to the surface layer GND 302g, whereby the switch 104 and the GND 102 are connected. And are connected.
  • the switch control circuit 105 is provided on the back surface of the board, the pad 304 on the back surface of the board is connected to the pad 302p on the front surface of the board by the interlayer via 303b, and the ball bump of the switch 104 is connected to the pad 302p, so that the switch 104 is connected. It is controlled by the switch control circuit 105.
  • the length of the interlayer via 303b is long because it penetrates the circuit board 300, but since a DC voltage is applied, it does not radiate unnecessary electromagnetic waves.
  • the ball bumps of the RF circuit 106 correspond to the transmission RF terminal or the reception RF terminal, respectively, and are connected to the antenna pattern 302a formed on the substrate surface via the pad and the line.
  • the antenna 101 and the line 103 are microstrip antennas and microstrip lines, and a GND pattern 301g which is a counter electrode and is given a reference potential is arranged below the line pattern corresponding to the antenna pattern 302a and the line 103.
  • FIG. 4 shows the radiation characteristics in the left-right direction (wide-angle radiation side, corresponding to the direction perpendicular to the longitudinal direction of the feeding line 122 in FIG. 2A) by the series-fed type antenna in which 10 radiation elements are arranged in series.
  • the horizontal axis shows the azimuth and the vertical axis shows the antenna gain.
  • the half width of the antenna is about 70 °, which is the same as the radiation characteristics of the unarrayed radiation elements.
  • the gain at an azimuth angle of 75 ° is 10 dB or more lower than the maximum gain.
  • the fact that the gain at an azimuth of 75 ° is 10 dB lower than the maximum gain obtained at the frontal direction (azimuth of 0 °) means that the detection distance of obstacles at an azimuth of 75 ° exists in the frontal direction. It means that it is about 1/3 of the detection distance of the obstacle. Therefore, in order to increase the reception sensitivity in a wide angle azimuth, it is important to widen the half width of the antenna and level the antenna gain with respect to a wider azimuth angle.
  • the transmitting antenna 131 of this embodiment will be described. As shown in FIG. 1, the transmitting antenna 131 is arranged on both sides of the feeding antenna 101T 1 connected to the transmitting terminal of the RF circuit 106 in the left-right direction (direction perpendicular to the feeding direction of the antenna), and is arranged in the RF circuit. It has non-feeding antennas 101T 2 and 101T 3 that are not connected to the transmission terminal of 106. The non-feeding antennas 101T 2 and 101T 3 are connected to the GND 102 via the switch unit 110, respectively.
  • the antenna 101 of this embodiment adopts a standing wave excitation type antenna, even if the antenna 101T 2 or the antenna 101T 3 is connected to the GND 102, it is fixed by the radiated radio wave excited by the adjacent feeding antenna 101T 1. In-wave excitation is induced.
  • the switch unit 110 includes two lines 103 and a switch 104. One end of the first line 103a is connected to the antenna 101T 2 , and the other end is connected to the switch 104.
  • the switch 104 switches the connection between the antenna 101T 2 and the GND 102 between the first path and the second path by the switch control circuit 105. The same applies to the switch portion provided on the antenna 101T 3.
  • the first route is a route connecting to the GND 102 via the first line 103a and the second line 103b, and the second route connects the first line 103a to the GND 102 without passing through the second line 103b. This is the route to connect. It is assumed that each of the lines 103 has an electric length of ⁇ g / 4.
  • the line length seen from the input terminals of the non-feeding antennas 101T 2 and 101T 3 is a path of ⁇ g / 4. Differences can be made.
  • FIG. 5 shows changes in the radiation characteristics of the transmitting antenna 131 having the layout shown in FIG. 2B by switching the route connecting the non-feeding antennas 101T 2 and 101T 3 to the GND 102.
  • the length of ⁇ g depends on the dielectric constant of the resin substrate forming the antenna, so the physical length in this example is a value when the dielectric constant of the resin substrate is 3.
  • FIG. 5 shows the azimuth angle on the horizontal axis and the antenna gain on the vertical axis. This is the radiation characteristic when the feeding antenna is connected to the GND 102 by the first path. In this way, when the non-feeding antenna is connected to the GND 102 through the first path, the antenna gain in the front direction is lower than when it is connected to the GND 102 through the second path, and the antenna in the wide angle direction is used. It can be seen that the gain is increasing.
  • FIG. 6 shows the antenna gain at 0 ° in the front direction when the line length connecting the non-feeding antennas 101T 2 , 101T 3 and the GND 102 is changed in the transmitting antenna 131 having the layout shown in FIG. 2B.
  • the antenna gain in the front direction repeatedly takes a maximum value in a cycle of 1.2 mm in line length, and obtains a minimum value in the middle.
  • the antenna gain in the front direction becomes the maximum value, and the phase of the feeding antenna 101T 1 and the non-feeding antenna 101T 2 ,.
  • the antenna gain in the front direction is the minimum value.
  • the antenna gain is the antenna half-value width 110 °
  • the maximum gain is the antenna gain 11.5 dBi at the azimuth angle 30 ° and the antenna gain 5 dBi at the azimuth angle 75 °. It can be read that there is.
  • the antenna gain due to one radiation element is suppressed in the front direction and improved in the wide angle direction. It is possible to obtain a leveled antenna gain for a wider range of orientations.
  • This antenna gain control is linked with the driving support system of the car. Since medium- and short-range radars are used for peripheral monitoring, it is desirable to have a high antenna gain in a wide-angle direction, but at high vehicle speeds (for example, 20 km / h or more), obstacles in front can be detected earlier. In order to detect it, there are cases where it is desired to increase the reception sensitivity in the front direction. In addition, there are situations where it is desirable to lower the detection priority of wide-angle obstacles in order to focus the resources of the driving support system in the direction of travel when the vehicle is driving straight. Therefore, in the radar sensor of this embodiment, the antenna gain can be switched between frontal direction priority and wide angle direction priority according to the operating situation.
  • FIG. 7A is a block diagram of a radar sensor system that can be linked with a driving support system.
  • the switch control circuit 105 of the radar sensor 100 controls the antenna gain based on the driving information of the vehicle collected by the ADAS (Advanced Driver-Assistance Systems) ECU 701.
  • the ADAS ECU 701 obtains the vehicle speed from the position information from the GPS device 702, the wheel speed information from the vehicle control device 704, and the like, and obtains the traveling direction information of the vehicle from the traffic information from the navigation device 703 and the communication device 705.
  • GPS device 702, navigation device 703, communication device 705 can obtain road branch point information.
  • the switch control circuit 105 obtains the vehicle speed, the traveling direction information, and the road branch point information of the own vehicle from the ADAS ECU 701.
  • the ADAS ECU 701 collects information from road-to-vehicle communication (V2I), vehicle cloud-to-cloud communication (V2C), and vehicle-pedestrian communication (V2P) as traveling information other than the information from these devices.
  • the switch control circuit 105 can also control the antenna gain based on these running information collected by the ADAS ECU 701.
  • FIG. 7B shows a flowchart of the antenna gain control operation of the radar sensor by the switch control circuit 105.
  • the switch control circuit 105 sets the antenna gain to the wide-angle mode (S01) and executes radar measurement (S02).
  • S01 wide-angle mode
  • S02 radar measurement
  • the determination order of the three conditions is not limited to the order shown in the flowchart. Further, the method for determining the three conditions is not particularly limited.
  • the switch control circuit 105 connects the non-feeding antenna to GND on the first path (line length is ⁇ g / 2), and in the narrow-angle mode, the switch control circuit 105 connects the non-feeding antenna to the second path.
  • the half-value width of the antenna radiation (referred to as wide-angle radiation) in the wide-angle mode is wider than the half-value width of the antenna radiation (referred to as narrow-angle radiation) in the narrow-angle mode.
  • the first condition is the vehicle speed (S03), the wide-angle mode is maintained in the case of low speed, and the determination of the second condition proceeds in the case of high speed.
  • the second condition is the traveling direction of the vehicle (S04), the wide-angle mode is maintained in the case of non-straight travel, and the determination of the third condition proceeds in the case of straight travel.
  • the third condition is whether the vehicle is approaching a road junction such as an intersection or a T-junction (S05). If the vehicle is approaching the road junction, the wide-angle mode is maintained and the vehicle approaches the road junction. If not, the mode is switched to the narrow angle mode (S06).
  • the upper limit of the number of narrow-angle distance measurements is set to 4 here, but the setting is not limited to this, and the set number may be a natural number of 1 or more.
  • the maximum number of times the vehicle can return to the wide-angle mode can be arbitrarily changed according to the vehicle operating conditions (driving speed, lane change, turning, etc.). Further, by forcibly setting the upper limit of the number of narrow-angle distance measurements to a negative value, it is possible to forcibly prevent the antenna gain control operation of the radar sensor.
  • the present invention is not limited to this. That is, as shown in FIG. 6, when the line length between the signal terminal of the non-feeding antenna and the GND is an even multiple (including 0) of ⁇ g / 4, the antenna gain becomes a wide-angle radiation state and no feeding is performed. When the line length between the signal terminal of the antenna and the GND is an odd multiple of ⁇ g / 4, the antenna gain is in a narrow-angle radiation state. Therefore, by switching the switch 104, the line length may be switched between the wide-angle radiation state and the narrow-angle radiation state. For example, by setting the line length of the first line 103a to an even multiple of ⁇ g / 4 and the line length of the second line 103b to an odd multiple of ⁇ g / 4, the antenna gain can be switched. It is possible.
  • the radar sensor is fixed, or even if it moves, its moving speed is low (for example, 10 km / h or less), so that the antenna gain may be fixed to the wide-angle radiation state.
  • the upper limit of the number of narrow-angle distance measurements may be set to 0 or less in the flow of FIG. 7B, or the non-feeding antenna may be always connected to the GND by the first path (line length is ⁇ g / 2). ..
  • the configuration of the radar sensor in this case is shown in FIG.
  • the non-feeding antennas 101T 2 and 101T 3 are connected to the GND 102 via a line 801 having a line length of ⁇ g / 2.
  • the line length of the line 801 may be an integral multiple of ⁇ g / 2.
  • FIG. 9 is a configuration example of the radar sensor of the second embodiment.
  • the radar sensor shown in FIG. 9 is provided with a plurality of transmitting antennas so that a virtual antenna having a MIMO configuration can be configured.
  • the antenna spacing dr of the receiving antenna is ⁇ / 2
  • the antenna spacing between the feeding antenna and the non-feeding antenna in the transmitting antenna 131 is also ⁇ / 2.
  • the antenna spacing dt is set to any other distance, it can be used as unequal spacing MIMO.
  • FIG. 10 further enables the radar sensor shown in FIG. 9 to switch between the wide-angle radiation state and the narrow-angle radiation state for the receiving antenna. Also in this example, as described in FIG. 2B, the antenna distance between the feeding antenna and the non-feeding antenna in the transmitting antenna 131 is ⁇ / 2.
  • passive antenna is shared between the receiving antenna 132 adjacent, in the radar sensor, with respect to the number nr fed antenna 101R 1, the number of parasitic antenna 101R 2 has a (nr + 1).
  • the receiving antenna 132 can switch between wide-angle radiation and narrow-angle radiation for radar distance measurement.
  • the antenna distance dr2 between the feeding antennas of the receiving antennas 132 arranged adjacent to each other is difficult to arrange at ⁇ / 2 due to the intervention of the non-feeding antenna, and the radar viewing angle according to the relational expression (Equation 3) is It gets narrower.
  • the antenna spacing d of the virtual receiving antenna can be defined as the following (Equation 4) based on the antenna spacing dt of the transmitting antenna 131 and the antenna spacing dr2 of the receiving antenna 132.
  • the virtual antenna arrangement obtained by this MIMO configuration partially lacks the received signal as an evenly spaced MIMO, it can be calculated as an evenly spaced MIMO by performing interpolation processing and extrapolation processing.
  • the sensitivity ratio of the received signal of the obstacle is obtained by using the MIMO configuration of the transmitting antenna group capable of wide-angle radiation and the receiving antenna group having the interval ⁇ / 2. Is alleviated, so that a plurality of obstacle peaks can be extracted without being hidden by the slope in the FFT process. Further, in the configuration of FIG. 10, the reception sensitivity in the wide angle direction is improved, so that it becomes possible to detect an obstacle farther away.
  • the line length of the line connecting the non-feeding antenna of the transmitting antenna or the receiving antenna to the GND is set to an integral multiple of ⁇ g / 2. It should be fixed.
  • FIG. 11 is a circuit diagram of the switch unit 110.
  • the source / drain path of the transistor (switch) 104 and the second line 103b are connected in parallel to one end of the first line 103a.
  • the transistor 104 is turned off by the control signal from the switch control circuit 105, a signal flows through the first line 103a and the second line 103b connected in series, and the control signal from the switch control circuit 105.
  • the connection point 125 is short-circuited to the GND 102.
  • the entire switch unit 110 With millimeter-wave band semiconductor devices, it is difficult to design high impedance due to parasitic capacitance even in the OFF state, but since an ON / OFF ratio of about 80 can be obtained, it is possible to select a line for GND102. be. It is also possible to make the entire switch unit 110 into an MMIC (Monolithic Microwave Integrated Circuit) and manufacture it by a semiconductor process. By surface-mounting a BGA (BallGridArray) on a circuit board as a three-terminal semiconductor chip, the switch unit 110 can be realized with high accuracy and the parasitic component due to connection can be suppressed to a low level.
  • MMIC Monitoring Microwave Integrated Circuit
  • FIG. 12 is another circuit diagram of the switch unit 110.
  • the switch unit 110 is composed of a line 103 and a variable phase line 126.
  • the liquid crystal has a molecular orientation that changes according to an external bias electric field, which changes the dielectric constant.
  • the circuit of FIG. 12 uses a liquid crystal board as the circuit board.
  • the variable phase line 126 is configured such that a GND pattern is formed on the back surface of the liquid crystal substrate, a line pattern is formed on the front surface of the liquid crystal substrate, and a bias voltage is applied to the line pattern from the bias power supply 127. There is.
  • the phase can be changed equivalently.
  • the switch control circuit 105 controls the bias voltage generated by the bias power supply 127 to change the phase of the variable phase line 126, so that the entire switch unit 110 has a line equivalent to an electric length of ⁇ g / 4 or an electric length of ⁇ g / 2. Realize a considerable track. If the switch unit shown in FIG. 12 is realized on the non-feeding antenna of the transmitting antenna 131 or the receiving antenna 132, simpler mounting is possible on the antenna board itself of the radar sensor 100 without using a semiconductor device.

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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)
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  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Waveguide Aerials (AREA)
  • Details Of Aerials (AREA)

Abstract

Il est prévu un capteur radar doté d'une antenne de transmission qui a un gain d'antenne amélioré par rapport à des éléments de rayonnement non disposés en réseau avec un azimut grand angle. Capteur radar comprenant un circuit imprimé 300, une couche conductrice 301 placée à l'intérieur du circuit imprimé et présentant un motif GND auquel est appliqué un potentiel de référence, et un motif conducteur 302 qui est placé sur la surface du circuit imprimé. Une antenne de transmission 131 et une antenne de réception sont des antennes d'excitation à ondes stationnaires. L'antenne de transmission comprend une antenne d'alimentation électrique 101T1 qui est connectée à une borne haute fréquence de transmission d'un circuit haute fréquence 106 et des antennes de non-alimentation électrique 101T2, 101T3 qui sont placées de part et d'autre dans une direction qui est perpendiculaire à la direction longitudinale d'une ligne d'alimentation électrique de l'antenne d'alimentation électrique. Les antennes de non-alimentation électrique sont connectées au motif GND par des lignes 103a, b. La longueur électrique desdites lignes 103a, b est λg/2 ou un multiple entier de celle-ci, λg étant la longueur d'onde le long des lignes d'ondes radio rayonnées par des éléments de rayonnement.
PCT/JP2021/002041 2020-06-25 2021-01-21 Capteur radar et système de capteur radar WO2021260983A1 (fr)

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JP2020-109726 2020-06-25
JP2020109726A JP7549979B2 (ja) 2020-06-25 2020-06-25 レーダセンサおよびレーダセンサシステム

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007037077A (ja) * 2004-09-30 2007-02-08 Toto Ltd マイクロストリップアンテナ及びマイクロストリップアンテナを用いた高周波センサ
WO2019120672A1 (fr) * 2017-12-20 2019-06-27 Robert Bosch Gmbh Dispositif d'émission et de réception de rayonnement électromagnétique

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007037077A (ja) * 2004-09-30 2007-02-08 Toto Ltd マイクロストリップアンテナ及びマイクロストリップアンテナを用いた高周波センサ
WO2019120672A1 (fr) * 2017-12-20 2019-06-27 Robert Bosch Gmbh Dispositif d'émission et de réception de rayonnement électromagnétique

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JP2022022520A (ja) 2022-02-07
JP7549979B2 (ja) 2024-09-12
DE112021002448T5 (de) 2023-02-23

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