EP0779674A1 - Vehicle antenna directive in azimuth for tranmitting and/or receiving and corresponding diversity assembly of antennas - Google Patents

Vehicle antenna directive in azimuth for tranmitting and/or receiving and corresponding diversity assembly of antennas Download PDF

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Publication number
EP0779674A1
EP0779674A1 EP96460040A EP96460040A EP0779674A1 EP 0779674 A1 EP0779674 A1 EP 0779674A1 EP 96460040 A EP96460040 A EP 96460040A EP 96460040 A EP96460040 A EP 96460040A EP 0779674 A1 EP0779674 A1 EP 0779674A1
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EP
European Patent Office
Prior art keywords
vehicle
antenna
longitudinal axis
directions
antennas
Prior art date
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Ceased
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EP96460040A
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German (de)
French (fr)
Inventor
Jean-Pierre Rossi
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Orange SA
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France Telecom SA
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Publication of EP0779674A1 publication Critical patent/EP0779674A1/en
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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
    • H01Q1/325—Adaptation for use in or on road or rail vehicles characterised by the location of the antenna on the vehicle
    • H01Q1/3275—Adaptation for use in or on road or rail vehicles characterised by the location of the antenna on the vehicle mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk

Definitions

  • the field of the invention is that of wireless communications with mobile terminals. More specifically, the invention relates to antennas for transmitting and / or receiving signals intended to equip vehicles.
  • the invention can be applied to all types of communication (in particular radio broadcasting, radio telephony, etc.), whether the signals exchanged are analog or digital.
  • the vehicle can be oriented in any way relative to the base station (itself being connected, for example, to the wired telephone network), and the operation must be correct in all cases.
  • the car antennas used are either whip antennas (generally 1/4 wave) or collinear antennas.
  • the main reason for their use is their simplicity of manufacture and their omni-directionality (for the polarization considered).
  • the invention particularly aims to overcome the drawbacks mentioned above.
  • the invention aims to provide a new type of antenna for radiocommunications with mobiles, making it possible to limit the disturbances due to the loss of power, the presence of echoes and / or the rapid fluctuations of the received signal. , especially in the most sensitive cases.
  • a particular objective of the invention is to provide such an antenna which is simple to produce and implement, and therefore inexpensive, both in manufacturing and in installation.
  • another objective of the invention is also to provide such an antenna requiring no adjustment or any particular technical knowledge, so that this installation can possibly be carried out by the user himself.
  • the invention also aims to provide such an antenna, which is compatible with all radio systems, and which can if necessary be used to replace antennas already implemented.
  • an antenna for transmitting and / or receiving electromagnetic waves intended to equip a vehicle said antenna being fixed by report to said vehicle, and directive in azimuth, said antenna having significant gains in both directions (right and left) oriented perpendicular to the longitudinal axis of said vehicle, and small or zero gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle.
  • the antenna of the invention therefore goes completely against the assumptions of those skilled in the art. Indeed, we no longer try to have an omni-directional antenna, nor an antenna oriented towards a base station, but a directional antenna whose lobes are fixed relative to the vehicle (regardless of the orientation and movements of that -this).
  • the antenna according to the invention makes it possible to eliminate the radio waves coming in the direction of the street in which the vehicle is moving. This prevents, or at least limits, the reception of distant echoes (arriving with the longest delays), which are the most disturbing. In fact, the inventors have verified that distant echoes arrive most of the time in the direction of the street (in an urban environment).
  • the antenna of the invention has a maximum gain in directions oriented perpendicular to the longitudinal axis of said vehicle and having an inclination upward relative to the horizontal.
  • said inclination can be generated by a ground plane.
  • the antenna according to the invention can be an antenna of a type known per se.
  • it may be a loop antenna.
  • the plane defined by said loop is perpendicular to the longitudinal axis of said vehicle.
  • the antenna of the invention can be constituted by a linear array comprising at least two whip antennas placed parallel to the longitudinal axis of said vehicle.
  • the antenna of the invention also has a gain in the front-rear direction of said vehicle. This technique increases the average power received.
  • the antenna of the invention proves to be particularly advantageous in an urban environment. In the event that it proves to be less effective in rural areas or on motorways than a conventional omnidirectional antenna, provision can be made for a diversity of antennas.
  • the switching is for example controlled on the basis of information representative of the power received and / or of the spreading of the delays for each of the antennas, the choice being made so as to use the most efficient antenna for communication in each situation.
  • an antenna is provided for eliminating radio waves from the street in which the vehicle is traveling, as illustrated in FIGS. 1a and 1b.
  • an antenna 12 is used having low or even zero gains 13 A , 13 B in the directions of the rear and front of the vehicle.
  • the directions of greatest gain 14 A , 14 B are to the right and left of the vehicle.
  • the shaded area 15 schematically illustrates the antenna lobe.
  • FIG. 3 shows an embodiment of the invention.
  • the antenna 31 used is a loop antenna, of a type known per se.
  • the plane defined by the loop is perpendicular to the longitudinal direction 32 of the vehicle 33.
  • the inclination of the lobe upwards is generated by a ground plane, formed for example by the roof of the vehicle. Indeed, by placing a metal plate under the antenna, it prevents the latter from radiating downward, by masking effect.
  • the waves arriving from above are received at the same time as these same waves reflected on the plate. These are therefore reinforced accordingly.
  • Other means of reinforcing the antenna gain are of course conceivable.
  • an antenna having such a diagram consists in implementing a linear array of whip antennas (conventional per se) of a small number of elements (2 to 5 for example), placed in the direction of the vehicle.
  • this technique makes it possible to obtain a diagram with lateral directivity (or front-rear), but does not concern the inclination of the diagram upwards.
  • the invention is particularly advantageous in an urban environment, and in particular in the most unfavorable cases for propagation.
  • a measurement campaign was carried out to validate the invention, using a directional antenna in azimuth.
  • the base station was located 47 m high. 1600 measurements were carried out, covering an area of 3 km in diameter around the base station.
  • the quality of the links was determined by determining the following two parameters: the power received by the receiver and the spreading of the delays. We know that the received signal is better when the received power is stronger and the delay spread is weaker.
  • the antenna has a gain in the front-rear direction, we also note that, compared to an omni-directional antenna, for an opening between 5 ° and 60 ° we obtain a gain of a few dB on the received power , while the spreading of time limits is twofold. Despite this drawback, the use of such an orientation can prove to be advantageous, in particular in diversity, due to the increase in the average power received in this configuration.
  • the invention has not yet been tested in rural areas or on motorways.
  • the device fitted to the vehicle comprises means 35 for analyzing the efficiency of each of said antennas, for example from measurements of the power received and the spreading of the delays for each of them, which controls a switch 36 making it possible to always use the best antenna.
  • the other antenna used with the antenna 31 to make diversity is a directive antenna, fixed relative to the vehicle and having significant gains in the two front / rear directions, and gains weak or zero in both left / right directions.

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  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The antenna (22) is mounted on the roof of a vehicle and is directional, with gain provided to the left and right of the vehicle. The antenna has zero gain to the front and rear of the direction of travel of the vehicle. The antenna can also move in the azimuth direction. The antenna beam centre (21) is inclined at an upward angle, to avoid the vehicle roof area. The antenna properties allow communications paths perpendicular to the vehicle to be selected, reducing the returns from other vehicles.

Description

Le domaine de l'invention est celui des communications hertziennes avec des terminaux mobiles. Plus précisément, l'invention concerne les antennes d'émission et/ou de réception de signaux destinées à équiper des véhicules.The field of the invention is that of wireless communications with mobile terminals. More specifically, the invention relates to antennas for transmitting and / or receiving signals intended to equip vehicles.

L'invention peut s'appliquer à tous les types de communication ( notamment radio-diffusion, radio-téléphonie,...), que les signaux échangés soient analogiques ou numériques.The invention can be applied to all types of communication (in particular radio broadcasting, radio telephony, etc.), whether the signals exchanged are analog or digital.

Les réseaux de communication avec des terminaux mobiles (sans fil) sont actuellement en pleine expansion. Dans une telle situation, le signal entre deux correspondants passe par l'intermédiaire d'ondes radio (sur au moins une partie du chemin de transmission). On sait que ce passage par le "canal radio" introduit souvent une partie majeure des perturbations des transmissions. En effet, notamment, la multiplicité des situations qui peuvent être rencontrées empêche a priori toutes solutions parfaites.Communication networks with mobile (wireless) terminals are currently expanding. In such a situation, the signal between two correspondents passes via radio waves (on at least part of the transmission path). We know that this passage by the "radio channel" often introduces a major part of the disturbances of the transmissions. Indeed, in particular, the multiplicity of situations that can be encountered a priori prevents all perfect solutions.

Parmi les perturbations les plus pénalisantes, on distingue en particulier la perte de puissance entre l'émetteur et le récepteur, la présence d'échos du signal, due au fait que le signal arrive par plusieurs trajets (par exemple par réflexion sur les éléments de l'environnement) et les fluctuations rapides du signal reçu (évanouissements de Rayleigh). On sait que, dans le cas des transmissions numériques, le phénomène d'échos est particulièrement sensible.Among the most penalizing disturbances, one distinguishes in particular the loss of power between the transmitter and the receiver, the presence of echoes of the signal, due to the fact that the signal arrives by several paths (for example by reflection on the elements of environment) and rapid fluctuations in the received signal (Rayleigh fading). We know that, in the case of digital transmissions, the phenomenon of echoes is particularly sensitive.

On peut réduire ces différents problèmes en améliorant les systèmes (par exemple : utilisation d'égaliseurs, augmentation de la puissance émise ou du nombre de sites d'émission). Toutefois, dans un contexte commercial, le coût de ces mesures les rend difficiles à mettre en oeuvre. Par ailleurs, certaines solutions techniques efficaces ne peuvent plus être mises en oeuvre sur des réseaux existants à cause des changements de structure impliqués.These various problems can be reduced by improving the systems (for example: using equalizers, increasing the transmitted power or the number of transmission sites). However, in a commercial context, the cost of these measures makes them difficult to implement. In addition, certain effective technical solutions can no longer be implemented on existing networks due to the structural changes involved.

Du point de vue des terminaux mobiles, on a envisagé de nombreuses améliorations. Notamment, de nombreux types d'antennes d'émission et/ou de réception ont été présentés. Ces antennes étant destinées à des mobiles, et notamment à des véhicules incorporant un terminal, l'homme du métier a toujours considéré que leur qualité principale doit être l'omni-directionnalité.From the point of view of mobile terminals, many improvements have been envisaged. In particular, many types of transmit and / or receive antennas have been presented. These antennas being intended for mobiles, and in particular for vehicles incorporating a terminal, the skilled person has always considered that their main quality must be omni-directionality.

En effet, le véhicule peut être orienté de manière quelconque par rapport à la station de base (elle-même étant reliée, par exemple, au réseau téléphonique filaire), et le fonctionnement doit être correct dans tous les cas.Indeed, the vehicle can be oriented in any way relative to the base station (itself being connected, for example, to the wired telephone network), and the operation must be correct in all cases.

Dans les systèmes actuels, les antennes de voitures utilisées sont soit des antennes fouet (généralement 1/4 d'onde) ou des antennes colinéaires. La raison principale de leur emploi est leur simplicité de fabrication et leur omni-directionnalité (pour la polarisation considérée).In current systems, the car antennas used are either whip antennas (generally 1/4 wave) or collinear antennas. The main reason for their use is their simplicity of manufacture and their omni-directionality (for the polarization considered).

On sait que les antennes directives sont plus efficaces, et que l'on obtiendrait un gain important dans le cas où le véhicule est bien orienté. Mais la communication serait fortement dégradée dans le cas contraire. Pour s'adapter aux changements d'orientation du véhicule, une antenne directive devrait donc réorienter en permanence son lobe principal dans la direction appropriée. En milieu urbain notamment, l'antenne devrait donc en permanence rechercher la meilleure position. De telles antennes ne sont pas envisageables sur un plan économique. En conséquence, tous les systèmes connus reposent sur la mise en oeuvre d'antennes omni-directionnelles.We know that the directional antennas are more effective, and that we would obtain a significant gain in the case where the vehicle is well oriented. But communication would be greatly degraded otherwise. To adapt to changes in vehicle orientation, a directive antenna should therefore constantly reorient its main lobe in the appropriate direction. In urban areas in particular, the antenna should therefore constantly seek the best position. Such antennas cannot be envisaged from an economic point of view. Consequently, all known systems are based on the use of omni-directional antennas.

L'invention a notamment pour objectif de pallier les inconvénients mentionnés ci-dessus.The invention particularly aims to overcome the drawbacks mentioned above.

Plus précisément, l'invention a pour objectif de fournir un nouveau type d'antenne pour les radiocommunications avec les mobiles, permettant de limiter les perturbations dues à la perte de puissance, la présence d'échos et/ou les fluctuations rapides du signal reçu, notamment dans les cas les plus sensibles.More specifically, the invention aims to provide a new type of antenna for radiocommunications with mobiles, making it possible to limit the disturbances due to the loss of power, the presence of echoes and / or the rapid fluctuations of the received signal. , especially in the most sensitive cases.

Un objectif particulier de l'invention est de fournir une telle antenne qui soit simple à réaliser et à mettre en oeuvre, et donc peu coûteuse, tant à la fabrication qu'à l'installation.A particular objective of the invention is to provide such an antenna which is simple to produce and implement, and therefore inexpensive, both in manufacturing and in installation.

En ce qui concerne l'installation, un autre objectif de l'invention est encore de fournir une telle antenne ne nécessitant aucun réglage ni aucune connaissance technique particulière, de façon que cette installation puisse éventuellement être effectuée par l'utilisateur lui-même.With regard to the installation, another objective of the invention is also to provide such an antenna requiring no adjustment or any particular technical knowledge, so that this installation can possibly be carried out by the user himself.

L'invention a également pour objectif de fournir une telle antenne, qui soit compatible avec tous les systèmes radio, et qui puisse le cas échéant être utilisée en remplacement d'antennes déjà mises en oeuvre.The invention also aims to provide such an antenna, which is compatible with all radio systems, and which can if necessary be used to replace antennas already implemented.

Ces objectifs, ainsi que d'autres qui apparaîtront par la suite sont atteints selon l'invention à l'aide d'une antenne d'émission et/ou de réception d'ondes électromagnétiques destinée à équiper un véhicule, ladite antenne étant fixe par rapport audit véhicule, et directive en azimut, ladite antenne présentant des gains importants dans les deux directions (droite et gauche) orientées perpendiculairement à l'axe longitudinal dudit véhicule, et des gains faibles ou nuls dans les deux directions (avant et arrière) orientées parallèlement à l'axe longitudinal dudit véhicule.These objectives, as well as others which will appear subsequently, are achieved according to the invention using an antenna for transmitting and / or receiving electromagnetic waves intended to equip a vehicle, said antenna being fixed by report to said vehicle, and directive in azimuth, said antenna having significant gains in both directions (right and left) oriented perpendicular to the longitudinal axis of said vehicle, and small or zero gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle.

L'antenne de l'invention va donc complètement à l'encontre des a priori de l'homme du métier. En effet, on ne tente plus d'avoir une antenne omni-directionnelle, ni une antenne orientée vers une station de base, mais une antenne directionnelle dont les lobes sont fixes par rapport au véhicule (indépendamment de l'orientation et des déplacements de celui-ci).The antenna of the invention therefore goes completely against the assumptions of those skilled in the art. Indeed, we no longer try to have an omni-directional antenna, nor an antenna oriented towards a base station, but a directional antenna whose lobes are fixed relative to the vehicle (regardless of the orientation and movements of that -this).

L'antenne selon l'invention permet d'éliminer les ondes radio provenant dans la direction de la rue dans laquelle se déplace le véhicule. Ainsi, on empêche, ou à tout le moins on limite, la réception d'échos lointains (arrivant avec les délais les plus longs), qui sont les plus perturbants. En effet, les inventeurs ont vérifié que les échos lointains arrivent la plupart du temps dans la direction de la rue (en milieu urbain).The antenna according to the invention makes it possible to eliminate the radio waves coming in the direction of the street in which the vehicle is moving. This prevents, or at least limits, the reception of distant echoes (arriving with the longest delays), which are the most disturbing. In fact, the inventors have verified that distant echoes arrive most of the time in the direction of the street (in an urban environment).

Par ailleurs, le fait d'utiliser une antenne directionnelle implique un renforcement du signal reçu, dû au gain de l'antenne nécessairement plus fort.In addition, the fact of using a directional antenna implies a reinforcement of the received signal, due to the gain of the antenna necessarily stronger.

Enfin, en éliminant certains trajets, on réduit du même coup les interférences entre les trajets, et donc les risques d'évanouissements rapides.Finally, by eliminating certain paths, the interference between the paths is reduced at the same time, and therefore the risks of rapid fainting.

Préférentiellement, l'antenne de l'invention présente un gain maximal dans des directions orientées perpendiculairement à l'axe longitudinal dudit véhicule et présentant une inclinaison vers le haut par rapport à l'horizontale.Preferably, the antenna of the invention has a maximum gain in directions oriented perpendicular to the longitudinal axis of said vehicle and having an inclination upward relative to the horizontal.

En effet, cette technique permet de renforcer les trajets les plus directs, provenant la plupart du temps, et dans les cas les plus défavorables, par propagation au-dessus des toits.Indeed, this technique makes it possible to reinforce the most direct paths, coming most of the time, and in the most unfavorable cases, by propagation over the roofs.

De façon avantageuse, ladite inclinaison peut être engendrée par un plan de masse.Advantageously, said inclination can be generated by a ground plane.

L'antenne selon l'invention peut être une antenne de type connu en soi. Notamment, il peut s'agir d'une antenne en boucle. Dans ce cas, le plan défini par ladite boucle est perpendiculaire à l'axe longitudinal dudit véhicule.The antenna according to the invention can be an antenna of a type known per se. In particular, it may be a loop antenna. In this case, the plane defined by said loop is perpendicular to the longitudinal axis of said vehicle.

Selon un autre mode de réalisation, l'antenne de l'invention peut être constituée par un réseau linéaire comprenant au moins deux antennes fouet placés parallèlement à l'axe longitudinal dudit véhicule.According to another embodiment, the antenna of the invention can be constituted by a linear array comprising at least two whip antennas placed parallel to the longitudinal axis of said vehicle.

Selon encore un autre mode de réalisation, l'antenne de l'invention présente de plus un gain dans la direction avant-arrière dudit véhicule. Cette technique permet d'augmenter la puissance moyenne reçue.According to yet another embodiment, the antenna of the invention also has a gain in the front-rear direction of said vehicle. This technique increases the average power received.

Comme expliqué ci-dessus, l'antenne de l'invention s'avère particulièrement avantageuse en milieu urbain. Dans le cas où elle s'avérerait moins efficace en milieu rural ou sur autoroute qu'une antenne omnidirectionnelle classique, on peut prévoir de faire de la diversité d'antennes.As explained above, the antenna of the invention proves to be particularly advantageous in an urban environment. In the event that it proves to be less effective in rural areas or on motorways than a conventional omnidirectional antenna, provision can be made for a diversity of antennas.

L'invention concerne donc également un dispositif d'émission et/ou de réception d'ondes électromagnétiques pour véhicule, caractérisé en ce qu'il comprend :

  • au moins une première antenne fixe par rapport audit véhicule, directive en azimut et présentant des gains importants dans les deux directions (droite et gauche) orientées perpendiculairement à l'axe longitudinal dudit véhicule, et des gains faibles ou nuls dans les deux directions (avant et arrière) orientées parallèlement à l'axe longitudinal dudit véhicule ;
  • au moins une seconde antenne ; et
  • des moyens de commutation entre lesdites première et seconde antennes, en fonction des besoins.
The invention therefore also relates to a device for transmitting and / or receiving electromagnetic waves for a vehicle, characterized in that it comprises:
  • at least a first antenna fixed relative to said vehicle, directive in azimuth and having significant gains in both directions (right and left) oriented perpendicular to the longitudinal axis of said vehicle, and small or zero gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle;
  • at least a second antenna; and
  • switching means between said first and second antennas, as required.

La commutation est par exemple pilotée à partir d'une information représentative de la puissance reçue et/ou de l'étalement des délais pour chacune des antennes, le choix étant fait de façon à utiliser l'antenne la plus efficace pour la communication dans chaque situation.The switching is for example controlled on the basis of information representative of the power received and / or of the spreading of the delays for each of the antennas, the choice being made so as to use the most efficient antenna for communication in each situation.

Avantageusement, ladite seconde antenne appartient au groupe comprenant :

  • une antenne classique omnidirectionnelle ;
  • une antenne directive, fixe par rapport audit véhicule, et présentant des gains importants dans les deux directions (avant et arrière) orientées parallèlement à l'axe longitudinal dudit véhicule, et des gains faibles ou nuls dans les deux directions (droite et gauche) orientées perpendiculairement à l'axe longitudinal dudit véhicule.
Advantageously, said second antenna belongs to the group comprising:
  • a conventional omnidirectional antenna;
  • a directional antenna, fixed relative to said vehicle, and having significant gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle, and small or zero gains in both directions (right and left) oriented perpendicular to the longitudinal axis of said vehicle.

D'autres caractéristiques et avantages de l'invention apparaîtront plus clairement à la lecture de la description suivante d'un mode de réalisation préférentiel de l'invention, donné à titre de simple exemple illustratif et non limitatif, et des dessins annexés, parmi lesquels :

  • les figures 1a et 1b illustrent les lobes d'une antenne selon l'invention équipant un véhicule vu de dessus (figure 1a) et de devant (figure 1b);
  • la figure 2 présente un autre mode de mise en oeuvre de l'invention, dans lequel les lobes d'antenne sont inclinés vers le haut ;
  • la figure 3 illustre un véhicule équipé d'une antenne boucle et d'une antenne omnidirectionnelle.
Other characteristics and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment of the invention, given by way of simple illustrative and nonlimiting example, and of the appended drawings, among which :
  • Figures 1a and 1b illustrate the lobes of an antenna according to the invention fitted to a vehicle seen from above (Figure 1a) and from the front (Figure 1b);
  • FIG. 2 shows another embodiment of the invention, in which the antenna lobes are inclined upwards;
  • FIG. 3 illustrates a vehicle equipped with a loop antenna and an omnidirectional antenna.

Comme expliqué plus haut, l'homme du métier a toujours considéré qu'il fallait, dans le cas d'un mobile, ne privilégier aucune direction de propagation, pour que le mobile puisse recevoir dans les mêmes conditions quelle que soit l'orientation du véhicule.As explained above, the person skilled in the art has always considered that, in the case of a mobile, it should not favor any direction of propagation, so that the mobile can receive under the same conditions whatever the orientation of the vehicle.

Selon l'invention en revanche, on prévoit une antenne permettant d'éliminer les ondes radio provenant de la rue dans laquelle circule le véhicule, ainsi que cela est illustré en figures 1a et 1b.According to the invention, however, an antenna is provided for eliminating radio waves from the street in which the vehicle is traveling, as illustrated in FIGS. 1a and 1b.

Le véhicule 11 étant pratiquement tout le temps dans le sens de circulation de la rue, on utilise une antenne 12 présentant des gains faibles voire nuls 13A, 13B dans les directions de l'arrière et de l'avant du véhicule. Pour des raisons de symétrie, les directions de plus grand gain 14A, 14B se trouvent vers la droite et la gauche du véhicule. La zone grisée 15 illustre schématiquement le lobe d'antenne.The vehicle 11 being practically all the time in the direction of traffic on the street, an antenna 12 is used having low or even zero gains 13 A , 13 B in the directions of the rear and front of the vehicle. For reasons of symmetry, the directions of greatest gain 14 A , 14 B are to the right and left of the vehicle. The shaded area 15 schematically illustrates the antenna lobe.

Ainsi que cela est illustrée en figure 2, une amélioration peut être envisagée, lorsque le gain maximum 21 de l'antenne 22 ne se trouve pas dans le plan horizontal, mais présente une inclinaison vers le haut. Cela permet en effet de renforcer les trajets provenant par propagation au-dessus des toits, qui sont souvent, en milieu défavorable, les trajets les plus directs.As illustrated in FIG. 2, an improvement can be envisaged, when the maximum gain 21 of the antenna 22 is not in the horizontal plane, but has an upward tilt. This makes it possible to reinforce the paths coming by propagation over the roofs, which are often, in an unfavorable environment, the most direct paths.

La figure 3 présente un mode de mise en oeuvre de l'invention. L'antenne 31 utilisée est une antenne en boucle, de type connu en soi. Le plan défini par la boucle est perpendiculaire à la direction longitudinale 32 du véhicule 33.Figure 3 shows an embodiment of the invention. The antenna 31 used is a loop antenna, of a type known per se. The plane defined by the loop is perpendicular to the longitudinal direction 32 of the vehicle 33.

Avantageusement, l'inclinaison du lobe vers le haut est engendrée par un plan de masse, formé par exemple par le toit du véhicule. En effet, en plaçant une plaque de métal sous l'antenne, on empêche celle-ci de rayonner vers le bas, par effet de masquage. Les ondes arrivant par dessus sont reçues en même temps que ces mêmes ondes réfléchies sur la plaque. Celles-ci sont donc renforcées d'autant. D'autres moyens pour renforcer le gain d'antenne sont bien sûr envisageables.Advantageously, the inclination of the lobe upwards is generated by a ground plane, formed for example by the roof of the vehicle. Indeed, by placing a metal plate under the antenna, it prevents the latter from radiating downward, by masking effect. The waves arriving from above are received at the same time as these same waves reflected on the plate. These are therefore reinforced accordingly. Other means of reinforcing the antenna gain are of course conceivable.

Un autre mode de réalisation d'une antenne présentant un tel diagramme consiste à mettre en oeuvre un réseau linéaire d'antennes fouet (classiques en soi) d'un faible nombre d'éléments (2 à 5 par exemple), placés dans la direction du véhicule. Bien sûr, cette technique permet d'obtenir un diagramme avec directivité latérale (ou avant-arrière), mais ne concerne pas l'inclinaison du diagramme vers le haut.Another embodiment of an antenna having such a diagram consists in implementing a linear array of whip antennas (conventional per se) of a small number of elements (2 to 5 for example), placed in the direction of the vehicle. Of course, this technique makes it possible to obtain a diagram with lateral directivity (or front-rear), but does not concern the inclination of the diagram upwards.

D'autres modes de réalisation sont également envisageables, sans sortir du cadre de l'invention.Other embodiments are also possible, without departing from the scope of the invention.

Il est à noter que l'invention est particulièrement avantageuse en milieu urbain, et notamment dans les cas les plus défavorables pour la propagation.It should be noted that the invention is particularly advantageous in an urban environment, and in particular in the most unfavorable cases for propagation.

Une campagne de mesures a été effectué pour valider l'invention, à partir d'une antenne directionnelle en azimut. Dans cette campagne, la station de base était située à 47 m de hauteur. 1600 mesures ont été effectuées, couvrant un domaine de 3 km de diamètre autour de la station de base.A measurement campaign was carried out to validate the invention, using a directional antenna in azimuth. In this campaign, the base station was located 47 m high. 1600 measurements were carried out, covering an area of 3 km in diameter around the base station.

La qualité des liaisons a été déterminée en déterminant les deux paramètres suivants : la puissance reçue par le récepteur et l'étalement des délais. On sait que le signal reçu est meilleur quand la puissance reçue est plus forte et l'étalement des délais est plus faible.The quality of the links was determined by determining the following two parameters: the power received by the receiver and the spreading of the delays. We know that the received signal is better when the received power is stronger and the delay spread is weaker.

On a vérifié, lors de cette campagne, que, par rapport à une antenne omnidirectionnelle, l'utilisation d'une antenne ayant une directivité latérale ne dégradait pas la puissance moyenne reçue, quelle que soit l'ouverture horizontale du lobe d'antenne. En revanche, l'étalement des délais peut être réduit de moitié pour une ouverture horizontale du lobe d'antenne de 5°, et d'environ un tiers pour une ouverture de 120°.During this campaign, we verified that, compared to an antenna omnidirectional, the use of an antenna having a lateral directivity did not degrade the average power received, whatever the horizontal opening of the antenna lobe. On the other hand, the spreading of the delays can be reduced by half for a horizontal opening of the antenna lobe of 5 °, and by about a third for an opening of 120 °.

Si l'antenne présente un gain dans la direction avant-arrière, on constate de plus que, par rapport à une antenne omni-directionnelle, pour une ouverture comprise entre 5° et 60° on obtient un gain de quelques dB sur la puissance reçue, alors que l'étalement des délais est double. Malgré cet inconvénient, l'utilisation d'une telle orientation peut s'avérer intéressante, en particulier en diversité, du fait de l'augmentation de la puissance moyenne reçue dans cette configuration.If the antenna has a gain in the front-rear direction, we also note that, compared to an omni-directional antenna, for an opening between 5 ° and 60 ° we obtain a gain of a few dB on the received power , while the spreading of time limits is twofold. Despite this drawback, the use of such an orientation can prove to be advantageous, in particular in diversity, due to the increase in the average power received in this configuration.

L'invention n'a pas encore été testée en milieu rural ou sur autoroute. Dans le cas où une dégradation serait observée, on peut prévoir d'utiliser l'antenne 31 comme moyen pour faire de la diversité d'antennes, au moins une autre antenne, par exemple une antenne fouet classique 34 (qui est omnidirectionnelle), équipant également le véhicule.The invention has not yet been tested in rural areas or on motorways. In the event that degradation is observed, provision may be made to use the antenna 31 as a means for making the diversity of antennas, at least one other antenna, for example a conventional whip antenna 34 (which is omnidirectional), equipping also the vehicle.

Dans ce cas. le dispositif équipant le véhicule comprend des moyens 35 pour analyser l'efficacité de chacune desdites antennes, par exemple à partir de mesures de la puissance reçue et de l'étalement des délais pour chacune d'elles, qui contrôle un commutateur 36 permettant d'utiliser à tout moment la meilleure antenne.In that case. the device fitted to the vehicle comprises means 35 for analyzing the efficiency of each of said antennas, for example from measurements of the power received and the spreading of the delays for each of them, which controls a switch 36 making it possible to always use the best antenna.

Selon la variante déjà envisagée ci-dessus, l'autre antenne utilisée avec l'antenne 31 pour faire de la diversité est une antenne directive, fixe par rapport au véhicule et présentant des gains importants dans les deux directions avant/arrière, et des gains faibles ou nuls dans les deux directions gauche/droite.According to the variant already envisaged above, the other antenna used with the antenna 31 to make diversity is a directive antenna, fixed relative to the vehicle and having significant gains in the two front / rear directions, and gains weak or zero in both left / right directions.

Claims (9)

Antenne (12 ; 22 ; 31) d'émission et/ou de réception d'ondes électromagnétiques destinée à équiper un véhicule, caractérisée en ce qu'elle est fixe par rapport audit véhicule, et directive en azimut, et en ce qu'elle présente des gains importants dans les deux directions (droite et gauche) (14A, 14B) orientées perpendiculairement à l'axe longitudinal dudit véhicule, et des gains faibles ou nuls dans les deux directions (avant et arrière) orientées parallèlement à l'axe longitudinal dudit véhicule.Antenna (12; 22; 31) for transmitting and / or receiving electromagnetic waves intended to equip a vehicle, characterized in that it is fixed relative to said vehicle, and directive in azimuth, and in that it has significant gains in both directions (right and left) (14 A , 14 B ) oriented perpendicular to the longitudinal axis of said vehicle, and small or zero gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle. Antenne selon la revendication 1, caractérisée en ce qu'elle présente un gain maximal dans des directions orientées perpendiculairement à l'axe longitudinal dudit véhicule et présentant une inclinaison (21) vers le haut par rapport à l'horizontale.Antenna according to claim 1, characterized in that it has a maximum gain in directions oriented perpendicular to the longitudinal axis of said vehicle and having an inclination (21) upwards relative to the horizontal. Antenne selon la revendication 2, caractérisée en ce que ladite inclinaison est engendrée par un plan de masse.Antenna according to claim 2, characterized in that said inclination is generated by a ground plane. Antenne selon l'une quelconque des revendications 1 à 3, caractérisée en ce qu'il s'agit d'une antenne en boucle (31).Antenna according to any one of claims 1 to 3, characterized in that it is a loop antenna (31). Antenne selon la revendication 4, caractérisée en ce que le plan défini par ladite boucle (31) est perpendiculaire à l'axe longitudinal dudit véhicule (33).Antenna according to claim 4, characterized in that the plane defined by said loop (31) is perpendicular to the longitudinal axis of said vehicle (33). Antenne selon l'une quelconque des revendications 1 à 5, caractérisée en ce qu'elle est constituée par un réseau linéaire comprenant au moins deux antennes fouet placés parallèlement à l'axe longitudinal dudit véhicule.Antenna according to any one of claims 1 to 5, characterized in that it is constituted by a linear array comprising at least two whip antennas placed parallel to the longitudinal axis of said vehicle. Antenne selon l'une quelconque des revendications 1 à 6, caractérisé en ce que présente de plus un gain dans la direction avant-arrière dudit véhicule.An antenna according to any one of claims 1 to 6, characterized in that it also has a gain in the front-rear direction of said vehicle. Dispositif d'émission et/ou de réception d'ondes électromagnétiques pour véhicule, caractérisé en ce qu'il comprend : - au moins une première antenne fixe (31) par rapport audit véhicule, directive en azimut et présentant des gains importants dans les deux directions (droite et gauche) (14A, 14B) orientées perpendiculairement à l'axe longitudinal dudit véhicule, et des gains faibles ou nuls dans les deux directions (avant et arrière) orientées parallèlement à l'axe longitudinal dudit véhicule ; - au moins une seconde antenne ; et - des moyens (36) de commutation entre lesdites première et seconde antennes, en fonction des besoins. Device for transmitting and / or receiving electromagnetic waves for a vehicle, characterized in that it comprises: - at least a first fixed antenna (31) relative to said vehicle, directive in azimuth and having significant gains in both directions (right and left) (14 A , 14 B ) oriented perpendicular to the longitudinal axis of said vehicle, and small or zero gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle; - at least a second antenna; and - Means (36) for switching between said first and second antennas, as required. Dispositif selon la revendication 8, caractérisé en ce que ladite seconde antenne appartient au groupe comprenant : - une antenne classique omnidirectionnelle (34) ; - une antenne directive, fixe par rapport audit véhicule, et présentant des gains importants dans les deux directions (avant et arrière) orientées parallèlement à l'axe longitudinal dudit véhicule, et des gains faibles ou nuls dans les deux directions (droite et gauche) orientées perpendiculairement à l'axe longitudinal dudit véhicule. Device according to claim 8, characterized in that said second antenna belongs to the group comprising: - a conventional omnidirectional antenna (34); - a directional antenna, fixed relative to said vehicle, and having significant gains in both directions (front and rear) oriented parallel to the longitudinal axis of said vehicle, and small or zero gains in both directions (right and left) oriented perpendicular to the longitudinal axis of said vehicle.
EP96460040A 1995-12-15 1996-12-13 Vehicle antenna directive in azimuth for tranmitting and/or receiving and corresponding diversity assembly of antennas Ceased EP0779674A1 (en)

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FR9515311A FR2742585B1 (en) 1995-12-15 1995-12-15 TRANSMISSION AND / OR RECEPTION ANTENNA FOR AZIMUTH DIRECTIVE VEHICLE, AND DEVICE WITH DIVERSITY OF ANTENNAS
FR9515311 1995-12-15

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008110953A1 (en) * 2007-03-15 2008-09-18 Koninklijke Philips Electronics N.V. Antenna array for vehicles

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2161736A (en) * 1937-05-19 1939-06-06 Galvin Mfg Corp Automobile aerial
DE921335C (en) * 1951-09-27 1954-12-16 Lorenz C Ag Vehicle antenna system
US4080603A (en) * 1976-07-12 1978-03-21 Howard Belmont Moody Transmitting and receiving loop antenna with reactive loading
US4176356A (en) * 1977-06-27 1979-11-27 Motorola, Inc. Directional antenna system including pattern control
EP0184447A2 (en) * 1984-12-06 1986-06-11 Toyota Jidosha Kabushiki Kaisha Automobile antenna system
EP0360594A2 (en) * 1988-09-21 1990-03-28 Harada Industry Co., Ltd. Automobile loop antenna

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2161736A (en) * 1937-05-19 1939-06-06 Galvin Mfg Corp Automobile aerial
DE921335C (en) * 1951-09-27 1954-12-16 Lorenz C Ag Vehicle antenna system
US4080603A (en) * 1976-07-12 1978-03-21 Howard Belmont Moody Transmitting and receiving loop antenna with reactive loading
US4176356A (en) * 1977-06-27 1979-11-27 Motorola, Inc. Directional antenna system including pattern control
EP0184447A2 (en) * 1984-12-06 1986-06-11 Toyota Jidosha Kabushiki Kaisha Automobile antenna system
EP0360594A2 (en) * 1988-09-21 1990-03-28 Harada Industry Co., Ltd. Automobile loop antenna

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TAKEDA ET AL.: "FM MULTIPATH DISTORTION IN AUTOMOBILE RECEIVERS HAS BEEEN SIGNIFICANTLY REDUCED BY A NEW ANTENNA SYSTEM", IEEE TRANSACTIONS ON CONSUMER ELECTRONICS, vol. 26, no. 3, August 1980 (1980-08-01), NEW YORK US, pages 263 - 269, XP002008406 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008110953A1 (en) * 2007-03-15 2008-09-18 Koninklijke Philips Electronics N.V. Antenna array for vehicles

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FR2742585B1 (en) 1998-03-13

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