EP2253044A1 - Radar sensor with patch antenna for motor vehicles - Google Patents

Radar sensor with patch antenna for motor vehicles

Info

Publication number
EP2253044A1
EP2253044A1 EP09716878A EP09716878A EP2253044A1 EP 2253044 A1 EP2253044 A1 EP 2253044A1 EP 09716878 A EP09716878 A EP 09716878A EP 09716878 A EP09716878 A EP 09716878A EP 2253044 A1 EP2253044 A1 EP 2253044A1
Authority
EP
European Patent Office
Prior art keywords
radar sensor
patch
parasitic elements
patch antenna
patches
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP09716878A
Other languages
German (de)
French (fr)
Inventor
Michael Klar
Thomas Binzer
Klaus-Dieter Miosga
Oliver Brueggemann
Dirk Steinbuch
Juergen Seiz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP2253044A1 publication Critical patent/EP2253044A1/en
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • G01S13/88—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
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/005—Patch antenna using one or more coplanar parasitic elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
    • H01Q21/061—Two dimensional planar arrays
    • H01Q21/065—Patch antenna array
    • 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

Definitions

  • the invention relates to a radar sensor for motor vehicles, which has at least one patch antenna.
  • ACC Adaptive Cruise Control
  • PSS predictive safety systems
  • radar sensors are required that are capable of controlling the distance and to measure the relative speed of preceding vehicles.
  • DE 10 2006 032 539 A1 describes an angle-resolving multi-beam radar sensor in which several antenna patches are arranged side by side on a common horizontal line. The radar radiation emitted by the patches is radiated by a common lens and focused, and the radar echo is focused by the same lens back on the patches and received by them (monostatic antenna concept). Due to the offset of the patches slightly different horizontally Radiation and Hauptbulkeitsraumen, so that can be determined by comparing the phases and amplitudes of the signals obtained in different patches of the azimuth angle of the reflecting object.
  • This radar sensor works on the principle of an FMCW (Frequency Modulated Continuous Wave) radar.
  • the frequency of the radar radiation is ramped, for example, with a rising and a falling frequency ramp, so that the frequency differences between the transmitted and the received signal obtained on the two ramps not only the calculation of the signal delay time and thus the object distance, but also the Doppler shift and thus allow the relative speed of the object.
  • FMCW Frequency Modulated Continuous Wave
  • US Pat. No. 6,281,843 B1 discloses a planar broadband dipole antenna for the VHF, FM or UHF band, in which parasitic elements are arranged on both sides of the dipole elements. This is to suppress the dispersion of the waves radiated from the dipole element.
  • the object of the invention is to provide a better resolution in the distance and relative speed measurement in a radar sensor of the type mentioned with simple and inexpensive means.
  • the patch antennas are associated with parasitic elements to increase the bandwidth. While the lens of the radar sensor generally has a large bandwidth, ie, is transparent to radar radiation in a relatively wide frequency band, in conventional radar sensors the antenna patch has only a small bandwidth. It forms a resonator which has only a relatively sharply defined resonance frequency and can radiate radar radiation only at this frequency or in its immediate vicinity, while at frequencies which deviate more strongly from this frequency, the largest part of the injected signal is reflected.
  • the antenna patch parasitic elements ie, surface elements of electrically conductive material, spatially associated in such a way that the system of patch and parasitic elements as a whole has at least two slightly shifted mutually resonant frequencies, resulting in a larger bandwidth of the antenna ,
  • the greater bandwidth can be exploited for greater frequency modulation of the transmitted signal, so that at the same temporal resolution, the frequency ramps can be made steeper and, consequently, greater frequency differences between transmitted and received signal for a given distance and given relative speed. In this way, a better resolution of the radar sensor is made possible.
  • Another advantage of the invention is that, in a monostatic antenna concept, poorly reflected power returns to the mixer, which serves to mix the transmitted signal with the received signal and generate an intermediate frequency whose frequency indicates the difference in frequency between the transmitted and received signals , In addition, will - A -
  • the DC offset of the mixer diode which has a positive effect on the performance of the radar sensor, especially in the vicinity.
  • the antenna patches have a rectangular shape, and the - preferably also rectangular - parasitic elements are arranged on both sides of the patch parallel to the edges which extend in the direction parallel to the feed line.
  • a multi-beam radar sensor having a plurality of antenna patches arranged on a common baseline
  • the patches including the associated parasitic elements are arranged obliquely with respect to the baseline.
  • the parasitic elements belonging to different patches can then overlap one another in the direction of the baseline or can be arranged at least very densely, so that a compact arrangement of the patches can be realized despite the larger surface area required by the parasitic elements.
  • Fig. 1 is a schematic side view of a radar sensor according to the invention
  • FIG. 2 is a front view of antenna patches of the radar sensor of FIG. 1; FIG. and
  • Fig. 3 is an adaptation diagram of the radar sensor according to the invention.
  • a radar sensor for motor vehicles is schematically shown, which has a lens 10 and an approximately arranged in the focal plane of the line 10 board 12.
  • the circuit board 12 is formed by an electrically insulating substrate 14, at the side facing away from the lens 10 back a continuous electrically conductive ground layer 16 is attached.
  • a plurality of, for example four, patch antennas 18 (hereinafter referred to as "patches"), including the associated infeeds 20, are arranged on a base line (horizontal in use) perpendicular to the plane of the drawing in FIG.
  • each patch 18 two parasitic elements 22, 24 are assigned. The arrangement of the patches 18 and the parasitic elements 22, 24 can be seen more clearly in the front view in FIG.
  • the patches 18 have a rectangular shape and are connected to the feeds 20 via a (microstrip) feed line 26, respectively, which runs parallel to two opposite edges of the patch 18.
  • the parasitic elements 22 and 24 also have a rectangular shape and are disposed on opposite sides of the patch 18, respectively, in parallel and spaced from the edges of the patch, which are parallel to the feedline 26.
  • the length of the parasitic elements 22 in the direction parallel to the feed line corresponds to the length of the patches 18, but their width is slightly smaller.
  • the areas and distances of the parasitic elements to the patches 18 are tuned so that the system as a whole has two adjacent resonant frequencies causing an increase in bandwidth.
  • FIG. 3 shows an adaptation diagram for a single patch antenna according to FIG. 2.
  • S-parameter which is a measure of the proportion of the microwave power reflected in the feed
  • the S parameter should be greater than -10 dB.
  • This S parameter is indicated in FIG. 3 by a curve 28 which has two distinct, partially fused minima at the frequencies 74 GHz and about 77.5 GHz. The entire range of the curve 28 between 72 GHz and about 78 GHz is below -10 dB. The gives a usable bandwidth W of about 6 GHz.
  • the minima of the curve 28 that cause the increase in bandwidth correspond to the resonance frequencies caused by the parasitic elements 22, 24.
  • Fig. 2 it can be seen that the M supply lines 26 and consequently also the edges of the patches and the parasitic elements extend at an angle of 45 ° to a baseline A, on which the patches 18 are arranged.
  • the location of the patches 18 relative to the optical axis of the lens 10 determines the direction in which the radar radiation is mainly emitted.
  • the arrangement according to Fig. 2 makes it possible to choose the distances between the patches 18 so small that the main emission directions of the various antennas are close enough together without the belonging to different patches 18 parasitic elements 22, 24 come so close to each other they cause mutual interference.

Landscapes

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

Abstract

Radar sensor for motor vehicles, comprising at least one patch antenna (18), characterized in that parasitic elements (22, 24) are assigned to the patch antennas (18) for enlarging the bandwidth.

Description

Beschreibungdescription
Titeltitle
Radarsensor mit Patch-Antenne für KraftfahrzeugeRadar sensor with patch antenna for motor vehicles
Stand der TechnikState of the art
Die Erfindung betrifft einen Radarsensor für Kraftfahrzeuge, der mindestens eine Patch-Antenne aufweist.The invention relates to a radar sensor for motor vehicles, which has at least one patch antenna.
Für Fahrerassistenzsysteme in Kraftfahrzeugen, beispielsweise für ACC-Systeme (Adaptive Cruise Control) zur automatischen Abstandsregelung oder für vorausschauende Sicherheitssysteme (PSS; Predictive Safety System) , die automatisch eine bevorstehende Kollision erkennen müssen, werden Radarsensoren benötigt, die in der Lage sind, den Abstand und die Relativgeschwindigkeit vorausfahrender Fahrzeuge zu messen. Für diesen Zweck beschreibt z.B. DE 10 2006 032 539 Al einen winkelauflösenden Mehrstrahlradarsensor, bei dem mehrere Antennenpatches nebeneinander auf einer gemeinsamen horizontalen Linie angeordnet sind. Die von den Patches emittierte Radarstrahlung wird durch eine gemeinsame Linse abgestrahlt und gebündelt, und das Radarecho wird durch dieselbe Linse wieder auf die Patches fokussiert und von ihnen empfangen (monostatisches Antennenkonzept) . Aufgrund des Versatzes der Patches ergeben sich in der Horizontalen leicht unterschiedliche Abstrahl- und Hauptempfindlichkeitsrichtungen, so daß sich durch Vergleich der Phasen und Amplituden der von der in verschiedenen Patches erhaltenen Signale der Azimutwinkel des reflektierenden Objekts bestimmen läßt.For driver assist systems in automobiles, such as Adaptive Cruise Control (ACC) systems or predictive safety systems (PSS), which automatically detect an imminent collision, radar sensors are required that are capable of controlling the distance and to measure the relative speed of preceding vehicles. For example, DE 10 2006 032 539 A1 describes an angle-resolving multi-beam radar sensor in which several antenna patches are arranged side by side on a common horizontal line. The radar radiation emitted by the patches is radiated by a common lens and focused, and the radar echo is focused by the same lens back on the patches and received by them (monostatic antenna concept). Due to the offset of the patches slightly different horizontally Radiation and Hauptempfindlichkeitsrichtungen, so that can be determined by comparing the phases and amplitudes of the signals obtained in different patches of the azimuth angle of the reflecting object.
Dieser Radarsensor arbeitet nach dem Prinzip eines FMCW-Radars (Frequency Modulated Continuous Wave) . Die Frequenz der Radarstrahlung wird rampenförmig moduliert, beispielsweise mit einer steigenden und einer fallenden Frequenzrampe, so daß die auf den beiden Rampen erhaltenen Frequenzunterschiede zwischen dem gesendeten und dem empfangenen Signal nicht nur die Berechnung der Signallaufzeit und damit des Objektabstands, sondern auch der Dopplerverschiebung und damit der Relativgeschwindigkeit des Objekts erlauben.This radar sensor works on the principle of an FMCW (Frequency Modulated Continuous Wave) radar. The frequency of the radar radiation is ramped, for example, with a rising and a falling frequency ramp, so that the frequency differences between the transmitted and the received signal obtained on the two ramps not only the calculation of the signal delay time and thus the object distance, but also the Doppler shift and thus allow the relative speed of the object.
Aus US 6 281 843 Bl ist eine planare Breitband-Dipolantenne für das VHF, FM oder UHF-Band bekannt, bei der parasitäre Elemente auf beiden Seiten der Dipolelemente angeordnet sind. Dadurch soll die Dispersion der von dem Dipolelement abgestrahlten Wellen unterdrückt werden.US Pat. No. 6,281,843 B1 discloses a planar broadband dipole antenna for the VHF, FM or UHF band, in which parasitic elements are arranged on both sides of the dipole elements. This is to suppress the dispersion of the waves radiated from the dipole element.
Offenbarung der ErfindungDisclosure of the invention
Aufgabe der Erfindung ist es, bei einem Radarsensor der eingangs genannten Art mit einfachen und kostengünstigen Mitteln eine bessere Auflösung bei der Abstands- und Relativgeschwindigkeitsmessung zu ermöglichen.The object of the invention is to provide a better resolution in the distance and relative speed measurement in a radar sensor of the type mentioned with simple and inexpensive means.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß den Patch-Antennen parasitäre Elemente zur Vergrößerung der Bandbreite zugeordnet sind. Während die Linse des Radarsensors im allgemeinen eine große Bandbreite hat, d.h., für Radarstrahlung in einem relativ breiten Frequenzband durchlässig ist, weist bei herkömmlichen Radarsensoren das Antennenpatch nur eine geringe Bandbreite auf. Es bildet einen Resonator, der nur eine relativ scharf definierte Resonanzfrequenz hat und Radarstrahlung nur bei dieser Frequenz oder in deren unmittelbarer Nähe abstrahlen kann, während bei stärker von dieser Frequenz abweichenden Frequenzen der größte Teil des eingespeisten Signals reflektiert wird.This object is achieved in that the patch antennas are associated with parasitic elements to increase the bandwidth. While the lens of the radar sensor generally has a large bandwidth, ie, is transparent to radar radiation in a relatively wide frequency band, in conventional radar sensors the antenna patch has only a small bandwidth. It forms a resonator which has only a relatively sharply defined resonance frequency and can radiate radar radiation only at this frequency or in its immediate vicinity, while at frequencies which deviate more strongly from this frequency, the largest part of the injected signal is reflected.
Bei dem erfindungsgemäßen Radarsensor sind dem Antennenpatch parasitäre Elemente, d.h., Flächenelemente aus elektrisch leitfähigem Material, in der Weise räumlich zugeordnet, daß das System aus Patch und parasitären Elementen als Ganzes mindestens zwei leicht gegeneinander verschobene Resonanzfrequenzen aufweist, wodurch sich eine größere Bandbreite der Antenne ergibt. Die größere Bandbreite kann für eine stärkere Frequenzmodulation des gesendeten Signals ausgenutzt werden, so daß bei gleicher zeitlicher Auflösung die Frequenzrampen steiler gemacht werden können und sich folglich für einen gegebenen Abstand und gegebene Relativgeschwindigkeit größere Frequenzunterschiede zwischen gesendetem und empfangenem Signal ergeben. Auf diese Weise wird eine bessere Auflösung des Radarsensors ermöglicht.In the radar sensor according to the invention the antenna patch parasitic elements, ie, surface elements of electrically conductive material, spatially associated in such a way that the system of patch and parasitic elements as a whole has at least two slightly shifted mutually resonant frequencies, resulting in a larger bandwidth of the antenna , The greater bandwidth can be exploited for greater frequency modulation of the transmitted signal, so that at the same temporal resolution, the frequency ramps can be made steeper and, consequently, greater frequency differences between transmitted and received signal for a given distance and given relative speed. In this way, a better resolution of the radar sensor is made possible.
Ein weiterer Vorteil der Erfindung bestehen darin, daß bei einem monostatischen Antennenkonzept nur wenig reflektierte Leistung in den Mischer zurück gelangt, der zum Mischen des gesendeten Signals mit dem empfangenen Signal und zur Erzeugung einer Zwischenfrequenz dient, deren Frequenz den Frequenzunterschied zwischen gesendetem und empfangenen Signal angibt. Außerdem wird - A -Another advantage of the invention is that, in a monostatic antenna concept, poorly reflected power returns to the mixer, which serves to mix the transmitted signal with the received signal and generate an intermediate frequency whose frequency indicates the difference in frequency between the transmitted and received signals , In addition, will - A -
durch die erfindungsgemäße Maßnahme der Gleichspannungs-Offset der Mischerdiode minimiert, was sich positiv auf die Leistungsfähigkeit des Radarsensors insbesondere im Nahbereich auswirkt .minimized by the inventive measure the DC offset of the mixer diode, which has a positive effect on the performance of the radar sensor, especially in the vicinity.
Vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung sind in den abhängigen Ansprüchen angegeben.Advantageous embodiments and further developments of the invention are specified in the dependent claims.
Bevorzugt haben die Antennenpatches eine rechteckige Form, und die - vorzugsweise ebenfalls rechteckigen - parasitären Elemente sind beiderseits des Patches parallel zu den Kanten angeordnet, die in der Richtung parallel zur Speiseleitung verlaufen.Preferably, the antenna patches have a rectangular shape, and the - preferably also rectangular - parasitic elements are arranged on both sides of the patch parallel to the edges which extend in the direction parallel to the feed line.
Bei einem Mehrstrahlradarsensor mit mehreren auf einer gemeinsamen Grundlinie angeordneten Antennenpatches ist es zweckmäßig, wenn die Patches einschließlich der zugehörigen parasitären Elemente schräg in Bezug auf die Grundlinie angeordnet sind. Die zu verschiedenen Patches gehörenden parasitären Elemente können dann in Richtung der Grundlinie miteinander überlappen oder zumindest sehr dicht angeordnet werden, so daß sich trotz des durch die parasitären Elemente bedingten größeren Flächenbedarfs eine kompakte Anordnung der Patches realisieren läßt.In a multi-beam radar sensor having a plurality of antenna patches arranged on a common baseline, it is expedient if the patches including the associated parasitic elements are arranged obliquely with respect to the baseline. The parasitic elements belonging to different patches can then overlap one another in the direction of the baseline or can be arranged at least very densely, so that a compact arrangement of the patches can be realized despite the larger surface area required by the parasitic elements.
Kurze Beschreibung der ZeichnungenBrief description of the drawings
Ein Ausführungsbeispiel der Erfindung ist in den Zeichnungen dargestellt und in der nachfolgenden Beschreibung näher erläutert .An embodiment of the invention is illustrated in the drawings and explained in more detail in the following description.
Es zeigen: Fig. 1 eine schematische Seitenansicht eines erfindungsgemäßen Radarsensors;Show it: Fig. 1 is a schematic side view of a radar sensor according to the invention;
Fig. 2 eine Frontansicht von Antennenpatches des Radarsensors nach Fig. 1; undFIG. 2 is a front view of antenna patches of the radar sensor of FIG. 1; FIG. and
Fig. 3 ein Anpassungsdiagramm des erfindungsgemäßen Radarsensors .Fig. 3 is an adaptation diagram of the radar sensor according to the invention.
Ausführungsformen der ErfindungEmbodiments of the invention
In Fig. 1 ist schematisch ein Radarsensor für Kraftfahrzeuge dargestellt, der eine Linse 10 und eine annähernd in der Brennebene der Linie 10 angeordnete Platine 12 aufweist. Die Platine 12 wird durch ein elektrisch isolierendes Substrat 14 gebildet, an dessen von der Linse 10 abgewandter Rückseite eine durchgehende elektrisch leitende Masseschicht 16 angebracht ist. Auf der Vorderseite des Substrats 14 sind auf einer senkrecht zur Zeichenebene in Fig. 1 verlaufenden (im Einsatz horizontalen) Grundlinie mehrere, beispielsweise vier, Patch- Antennen 18 (im folgenden kurz "Patches") einschließlich der zugehörigen Einspeisungen 20 angeordnet.In Fig. 1, a radar sensor for motor vehicles is schematically shown, which has a lens 10 and an approximately arranged in the focal plane of the line 10 board 12. The circuit board 12 is formed by an electrically insulating substrate 14, at the side facing away from the lens 10 back a continuous electrically conductive ground layer 16 is attached. On the front side of the substrate 14, a plurality of, for example four, patch antennas 18 (hereinafter referred to as "patches"), including the associated infeeds 20, are arranged on a base line (horizontal in use) perpendicular to the plane of the drawing in FIG.
Auf diese Weise werden vier unabhängig voneinander ansteuerbare Mikrostrip-Patch-Antennen gebildet, die in der Lage sind, Radarstrahlung mit einer Frequenz in der Größenordnung von 77 GHz zu senden und zu empfangen. Die Linse 10 ist für Radarstrahlung in einem relativ breiten Frequenzband in der Umgebung des Wertes von 77 GHz durchlässig. Zur Vergrößerung der Bandbreite der Patch-Antennen sind jedem Patch 18 zwei parasitäre Elemente 22, 24 zugeordnet. Die Anordnung der Patches 18 und der parasitären Elemente 22, 24 ist deutlicher in der Frontansicht in Fig. 2 zu erkennen.In this way, four independently controllable microstrip patch antennas are formed, which are capable of transmitting and receiving radar radiation having a frequency of the order of 77 GHz. The lens 10 is transparent to radar radiation in a relatively wide frequency band in the vicinity of the value of 77 GHz. To increase the bandwidth of the patch antennas each patch 18 two parasitic elements 22, 24 are assigned. The arrangement of the patches 18 and the parasitic elements 22, 24 can be seen more clearly in the front view in FIG.
Die Patches 18 haben eine rechteckige Gestalt und sind mit den Einspeisungen 20 jeweils über eine (Mikrostrip-) Speiseleitung 26 verbunden, die parallel zu zwei gegenüberliegenden Kanten des Patches 18 verläuft. Die parasitären Elemente 22 und 24 haben ebenfalls eine rechteckige Gestalt und sind auf entgegengesetzten Seiten des Patches 18 jeweils parallel und in Abstand zu den Kanten des Patches angeordnet, die parallel zu der Speiseleitung 26 verlaufen. Die Länge der parasitären Elemente 22 in der Richtung parallel zur Speiseleitung entspricht der Länge der Patches 18, ihre Breite ist jedoch etwas geringer. Die Flächen und Abstände der parasitären Elemente zu den Patches 18 sind so abgestimmt, daß das System als Ganzes zwei einander benachbarte Resonanzfrequenzen aufweist, die eine Vergrößerung der Bandbreite bewirken.The patches 18 have a rectangular shape and are connected to the feeds 20 via a (microstrip) feed line 26, respectively, which runs parallel to two opposite edges of the patch 18. The parasitic elements 22 and 24 also have a rectangular shape and are disposed on opposite sides of the patch 18, respectively, in parallel and spaced from the edges of the patch, which are parallel to the feedline 26. The length of the parasitic elements 22 in the direction parallel to the feed line corresponds to the length of the patches 18, but their width is slightly smaller. The areas and distances of the parasitic elements to the patches 18 are tuned so that the system as a whole has two adjacent resonant frequencies causing an increase in bandwidth.
Dies ist in Fig. 3 zu erkennen, die ein Anpassungsdiagramm für eine einzelne Patch-Antenne nach Fig. 2 zeigt. In diesem Diagramm ist der sogenannte S-Parameter, der ein Maß für den Anteil der in die Einspeisung reflektierten Mikrowellenleistung ist, gegen die Frequenz aufgetragen. Je kleiner der (negative) S-Parameter ist, desto größer ist folglich die Sendeleistung der Antenne bei der betreffenden Frequenz.This can be seen in FIG. 3, which shows an adaptation diagram for a single patch antenna according to FIG. 2. In this diagram, the so-called S-parameter, which is a measure of the proportion of the microwave power reflected in the feed, is plotted against the frequency. Consequently, the smaller the (negative) S parameter, the greater is the transmission power of the antenna at the relevant frequency.
Für eine Anwendung als Radarsensor in Kraftfahrzeugen sollte der S-Parameter größer sein als -10 dB. Dieser S-Parameter wird in Fig. 3 durch eine Kurve 28 angegeben, die zwei deutliche, zum Teil miteinander verschmolzene Minima bei den Frequenzen 74 GHz und etwa 77,5 GHz aufweist. Der gesamte Bereich der Kurve 28 zwischen 72 GHz und etwa 78 GHz liegt unterhalb von -10 dB. Das ergibt eine nutzbare Bandbreite W von etwa 6 GHz . Die Minima der Kurve 28, die die Vergrößerung der Bandbreite bewirken, entsprechen den Resonanzfrequenzen, die durch die parasitären Elemente 22, 24 verursacht werden.For use as a radar sensor in automobiles, the S parameter should be greater than -10 dB. This S parameter is indicated in FIG. 3 by a curve 28 which has two distinct, partially fused minima at the frequencies 74 GHz and about 77.5 GHz. The entire range of the curve 28 between 72 GHz and about 78 GHz is below -10 dB. The gives a usable bandwidth W of about 6 GHz. The minima of the curve 28 that cause the increase in bandwidth correspond to the resonance frequencies caused by the parasitic elements 22, 24.
In Fig. 2 ist zu erkennen, daß die M Speiseleitungen 26 und folglich auch die Kanten der Patches und der parasitären Elemente unter einem Winkel von 45° zu einer Grundlinie A verlaufen, auf der die Patches 18 angeordnet sind.In Fig. 2 it can be seen that the M supply lines 26 and consequently also the edges of the patches and the parasitic elements extend at an angle of 45 ° to a baseline A, on which the patches 18 are arranged.
Die Lage der Patches 18 relativ zur optischen Achse der Linse 10 bestimmt die Richtung, in der die Radarstrahlung hauptsächlich emittiert wird. Die Anordnung nach Fig. 2 erlaubt es, die Abstände zwischen den Patches 18 so klein zu wählen, daß die Hauptabstrahlrichtungen der verschiedenen Antennen eng genug beieinander liegen, ohne daß die zu verschiedenen Patches 18 gehörenden parasitären Elemente 22, 24 einander so nahe kommen, daß sie gegenseitige Störungen verursachen. The location of the patches 18 relative to the optical axis of the lens 10 determines the direction in which the radar radiation is mainly emitted. The arrangement according to Fig. 2 makes it possible to choose the distances between the patches 18 so small that the main emission directions of the various antennas are close enough together without the belonging to different patches 18 parasitic elements 22, 24 come so close to each other they cause mutual interference.

Claims

Ansprüche claims
1. Radarsensor für Kraftfahrzeuge, der mindestens eine Patch- Antenne (18) aufweist, dadurch gekennzeichnet, daß den1. Radar sensor for motor vehicles, comprising at least one patch antenna (18), characterized in that the
Patch-Antennen (18) parasitäre Elemente (22, 24) zur Vergrößerung der Bandbreite zugeordnet sind.Patch antennas (18) are associated with parasitic elements (22, 24) for increasing the bandwidth.
2. Radarsensor nach Anspruch 1, dadurch gekennzeichnet, daß jede Patch-Antenne (18) eine rechteckige Form hat, und daß zwei rechteckige parasitäre Elemente (22, 24) beiderseits der Patch-Antenne (18) parallel und in Abstand zu zwei einander gegenüberliegenden Kanten derselben angeordnet sind.2. Radar sensor according to claim 1, characterized in that each patch antenna (18) has a rectangular shape, and that two rectangular parasitic elements (22, 24) on both sides of the patch antenna (18) parallel and at a distance from two opposite Edges of the same are arranged.
3. Radarsensor nach Anspruch 2, dadurch gekennzeichnet, daß mehrere Patch-Antennen (18) so auf einer gemeinsamen Grundlinie (A) auf einer gemeinsamen Platine (12) angeordnet sind, daß ihre Kanten schräg in Bezug auf die Grundlinie orientiert sind.3. Radar sensor according to claim 2, characterized in that a plurality of patch antennas (18) are arranged on a common base line (A) on a common board (12), that their edges are oriented obliquely with respect to the baseline.
4. Radarsensor nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß jede Patch-Antenne (18) eine Speiseleitung (26) aufweist, die parallel zu den Kanten verläuft, an denen die parasitären Elemente (22, 24) angeordnet sind. 4. Radar sensor according to claim 2 or 3, characterized in that each patch antenna (18) has a feed line (26) which runs parallel to the edges on which the parasitic elements (22, 24) are arranged.
5. Radarsensor nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die Patch-Antennen (18) als Mikrostrip-Patch-Antennen ausgebildet sind und die Speiseleitungen (26) durch Mikrostrip-Leitungen gebildet werden . 5. Radar sensor according to one of the preceding claims, characterized in that the patch antennas (18) are designed as microstrip patch antennas and the feed lines (26) are formed by microstrip lines.
EP09716878A 2008-03-04 2009-01-26 Radar sensor with patch antenna for motor vehicles Ceased EP2253044A1 (en)

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DE102008000502A DE102008000502A1 (en) 2008-03-04 2008-03-04 Radar sensor with patch antenna for motor vehicles
PCT/EP2009/050818 WO2009109418A1 (en) 2008-03-04 2009-01-26 Radar sensor with patch antenna for motor vehicles

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JP2013135345A (en) * 2011-12-26 2013-07-08 Fujitsu Ten Ltd Microstrip antenna, array antenna, and radar device
DE102015211384A1 (en) 2015-06-19 2016-12-22 Robert Bosch Gmbh Antenna arrangement, method for producing an antenna arrangement and method for operating an antenna arrangement
DE102018219986A1 (en) * 2018-11-22 2020-05-28 Robert Bosch Gmbh Printed circuit board for radar sensors with a metallic filling structure and method for producing a printed circuit board for radar sensors with a metallic filling structure

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JP4082725B2 (en) 1995-07-01 2008-04-30 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング Monostatic FMCW radar sensor
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