FR3056044B1 - DEVICE FOR TRANSMITTING AND / OR RECEIVING RADIO WITH ANTENNAS AND INDEPENDENT ASSOCIATED OPENINGS - Google Patents

Abstract

A radio transmission and / or reception device (D) is adapted to equip a system, and comprises a closed structure (SD) and comprising: - walls (P1-P2, PL1-PL4) conducting and defining a cavity ( CS), some of these walls (PL1-PL4) each comprising at least one aperture (01-04) having its own radiation pattern in space, and - at least one conductive inner wall (PI1-PI2) and subdividing this cavity (CS) in sub-cavities (SC1-SC4) each associated with at least one of the openings (01-04), so that the latter are independent of one another, and each housing at least one antenna (A1-A4 ) capable of converting electromagnetic waves passing through each associated opening (01-04) into electrical signals or electrical signals into electromagnetic waves suitable for passing through each associated opening (01-04).

Description

The invention relates to emission and / or reception devices which are installed in certain systems and which are used in radiocommunication or in radio direction-finding.

Some systems, such as for example certain vehicles, possibly motor vehicles, comprise at least one transmission and / or reception device enabling them to exchange messages by means of electromagnetic waves. Here we mean by "exchanging" the fact of either sending messages, receiving messages, or even sending and receiving messages.

These transmission and / or reception devices often comprise at least one radio antenna system comprising at least one antenna (or element), connected to an electrical circuit, and intended to radiate (or transmit) and / or or receive electromagnetic waves.

Antennas (or elements) of antennal systems can be realized according to different technologies, and in particular wired (for example quarter-wave or half-wave) or planar (for example cobblestone (s) (or "patch" ( es) ").

An antenna system is generally arranged in the form of a dipole or a monopole. An antenna system of the dipole type comprises two parts that can be assimilated to electrical poles and connected to an electrical connection that supplies them to radiate electromagnetic waves, or that receives and processes received electromagnetic waves. It is highly influenced by the surfaces of conductive materials that are located in its vicinity and that can change its electrical and electromagnetic characteristics.

A monopole-type antenna system uses a highly conductive surface (usually metal) to virtually create a second electrical pole. This surface, generally called "ground plane", acts as an electromagnetic mirror. Since the image of the monopole is reflected on the ground plane, the monopole-type antennal system is comparable to an antenna system of the dipole type with one pole connected to the antenna and the other pole connected to the ground plane. At least one of the dimensions of a monopole type antennal system is therefore considerably smaller than that of a dipole type antenna system. Furthermore, a monopole type antenna system can be installed directly and advantageously on a metal structure.

An antenna system is characterized by its radiation pattern and its electric equivalent model, whatever its type. It is recalled that the radiation pattern represents the gains in reception and / or emission according to the directions in space, and the equivalent electrical model of an antennal system results from the fact that it can be seen as an electrical element which is characterized by its electrical impedance. This electrical impedance determines the electrical impact that the antenna can have in its electrical supply or reception circuit.

Some antenna systems may be in the form of waveguides (elongated cavities, made of conductive material, forming an interior space often filled with air, and used for the transport of electromagnetic waves). The cross sections of these waveguides may have different shapes, including rectangular, square or circular. Note that the cavity of a waveguide can accommodate at least one antenna, usually at one of its ends to emit electromagnetic waves to propagate in the cavity or to receive electromagnetic waves propagating in the cavity. the cavity.

Since the electromagnetic waves propagate by reflecting on the conductive walls of the waveguide at predefined locations, slots (or openings) in the walls of this waveguide can be defined at abscissae. specific depending on the distribution of the electromagnetic field inside this waveguide and the surface current along it.

A transmitting and / or receiving device may comprise several waveguides (some of which have slots) intended to confer on it a single and specific overall radiation or reception pattern, resulting from the simultaneous contribution of the whole slots (amplitude and phase associated with each slot individually).

These slotted waveguides may be unsatisfactory in some applications. This is particularly the case for the exchange of messages between vehicles or between a vehicle and an infrastructure (for example of Car2X type), in particular when the slotted waveguide is installed at the roof level (or roof), whether either on the surface or in the structure. Indeed, it does not allow to obtain optimized radio coverage performance, with a directivity and sensitivity in dynamics according to the azimuth and elevation around the vehicle. Thus, it does not allow, for example, to obtain a better gain towards the front of the vehicle, a lower gain towards the rear of the vehicle, and a small gain on the sides of the vehicle. In addition, it does not correctly ensure a direction-finding function (determining the direction of arrival of an electromagnetic wave), and even less to provide both a direction-finding function and a radiocommunication function. The invention is therefore particularly intended to improve the situation.

It proposes for this purpose a device for transmitting and / or receiving radio proper to equip a system, and comprising a closed structure and comprising: - conductive walls and defining a cavity, some of these walls each comprising at least one opening having its own radiation pattern in space, and - at least one conductive inner wall and subdividing the cavity into sub-cavities each associated with at least one of the openings, so that the latter are independent of each other, and housing each at least one antenna capable of converting electromagnetic waves passing through each opening associated with its sub-cavity into electrical signals (intended for at least one electrical circuit) or electrical signals (provided by at least one electrical circuit) into electromagnetic waves specific to go through each opening associated with its under cavity.

Thus, there is a radio coverage having a directivity and sensitivity in dynamics according to the azimuth and elevation around the system.

The radio transmission and / or reception device according to the invention may comprise other characteristics that can be taken separately or in combination, and notably: in each sub-cavity, the dimensions of the latter and a location of each associated antenna can be adapted to the radiation pattern of each associated aperture and to a predefined impedance; it can comprise at least one electrical circuit capable of supplying electrical signals to at least one antenna and / or receiving electrical signals originating from at least one antenna; the electrical circuit can be clean in emission to combine in a chosen way the radiation patterns of the openings, and in reception to interpret and process in a chosen way the electrical signals coming from the antennas, in order to perform selected functions. The electrical circuit may be able to control respective amplitudes and / or respective phases of the electrical signals coming from the antennas or intended for the antennas; • the functions can be selected from a group comprising (at least) a radiocommunication function and a direction-finding function; the electrical circuit may comprise at least one antenna; it may comprise a conductive flat surface secured to a wall of the structure which is not a wall provided with an opening. The invention also proposes a vehicle, possibly of automobile type, and comprising at least one radio transmission and / or reception device of the type of that presented above.

In this case, the radio transmission and / or reception device may, for example, be part of a constituent of the vehicle chosen from (at least) a roof (or roof) and a lower part of a body structure , or be installed inside the vehicle. Other features and advantages of the invention will appear on examining the following detailed description, and the accompanying drawings, in which: FIG. 1 schematically illustrates, in a perspective view, an embodiment of FIG. a radio transmission and / or reception device according to the invention; FIG. 2 schematically illustrates, in a view from above, the radio transmission and / or reception device of FIG. 1; FIG. schematically an example of a global radiation pattern (in azimuth or in the horizontal plane) obtained with a radio transmission and / or reception device of the type of that illustrated in FIG. 1, and FIG. 4 schematically illustrates in FIG. FIG. 1 is an example of an evolution of the amplitudes of the electrical signals supplied in reception mode respectively by the antennas A1 to A4 of a transmitting and receiving device. dielectric of the type illustrated in FIG. 1, as a function of the azimuth angle of arrival of an electromagnetic wave. The object of the invention is in particular to propose a radio transmission and / or reception device D intended to equip a system and having a radio coverage having a directivity and a dynamic sensitivity as a function of the azimuthal angle (or azimuth).

In the following, we consider, by way of non-limiting example, that the system is a motor vehicle, such as a car. But the invention is not limited to this type of system. It concerns any type of system, including vehicles (land, sea (or fluvial), and aerospace), facilities, possibly industrial type, and buildings.

FIGS. 1 and 2 show schematically a nonlimiting exemplary embodiment of a radio transmission and / or reception device D according to the invention.

As illustrated, a device (radio transmission and / or reception) D, according to the invention, comprises a closed SD structure and comprising walls Pk (lower (k = 1) and higher (k = 2)) and PLj (Lateral) made of a conductive material and defining a cavity CS, at least one inner wall Pim made of a conductive material, and antennas Aj.

The walls Pk and PLj and each inner wall Pim may be made of a metallic material, such as aluminum or steel.

Among the walls Pk and PLj of the structure SD (which define the cavity CS), some of them each comprise at least one opening Oj which has its own radiation pattern in space.

In the example shown non-limitatively in FIGS. 1 and 2, the structure SD comprises four lateral walls PL1 to PL4 (j = 1 to 4), a "lower" wall P1 and an "upper" wall P2 which define together a cavity CS of parallelepipedal shape. As it appears better in FIG. 2, the parallelepiped here has a square base (the lower walls P1 and upper P2 are thus square). But this base could be rectangular.

Furthermore, in the example shown non-limitatively in Figures 1 and 2, the openings Oj are all respectively defined on the four side walls PLj. But at least one of the walls Pk could comprise at least one opening Oj.

It will be noted that the shape of the cavity CS is not necessarily geometric. It can indeed be any. This form depends on the application and its implementation or at least another constraint (such as style, aerodynamics, mechanics). Therefore, the number of side walls PLj can take any value greater than or equal to three or can be equal to one when a single side wall PLj closes on itself. In the latter case, it is considered that the single side wall PLj is subdivided into at least two sub-parts which each comprise at least one opening Oj.

The inner wall (s) Pim subdivides (s) the cavity CS into sub-cavities SCj which are each associated with at least one of the openings Oj, so that the latter (Oj) are independent of each other. other. This means that each sub cavity SCj communicates with the outside via at least one opening Oj defined in at least one of the walls Pk and PLj which partially delimit it.

In the example shown non-limitatively in FIGS. 1 and 2, the structure SD comprises four lateral walls PL1 to PL4 respectively provided with four openings 01 to 04. Consequently, the cavity CS is subdivided by two internal walls PU (m = 1 ) and PI2 (m = 2) into four sub-cavities SC1 to SC4 which are respectively associated with the four openings 01 to 04. It will be noted that instead of using two internal walls Pim one could use three or four.

But in alternative embodiments not illustrated, the cavity CS could be subdivided by a single inner wall into two sub-cavities or by at least two internal walls into at least two sub-cavities.

It will also be noted that at least one of the walls Pk and PLj could comprise at least two openings Oj.

Each sub-cavity SCj houses at least one antenna Aj which is adapted to convert electromagnetic waves passing through each associated aperture Oj into electrical signals (intended for at least one electrical circuit CE) or electrical signals (provided by at least one electrical circuit CE) in electromagnetic waves suitable for passing through each associated aperture Oj. The antennas Aj are therefore independent of each other.

In the example shown in non-limiting manner in FIGS. 1 and 2, the structure SD comprises four sub-cavities SC1 to SC4 which respectively house four antennas A1 to A4. It will be noted that at least one of the sub-cavities SCj could comprise at least two antennas Aj.

Here, the term "independent openings" means openings which are not defined periodically in the SD structure and which do not participate in a manner dependent on the overall contribution of their cavity CS (each opening Oj only contributes to the contribution of its sub cavity SCj).

The openings Oj may therefore have any shape and any location relative to each other as soon as their locations and shapes are adapted to the associated antenna Aj.

Thanks to the antennas Aj and Oj associated independent openings, there is now a radio coverage having a directivity and sensitivity in dynamics according to at least the azimuth (or azimuthal angle). The device D can indeed emit and / or receive electromagnetic waves in at least one main direction chosen with a sufficient gain and with minimal electromagnetic losses, thanks to the combination of the electrical and electromagnetic characteristics of the openings Oj and the associated antennas Aj according to their positions and shapes respectively on and in the cavity CS.

It will be noted that in each sub-cavity SCj the dimensions h, 11 and I2 of the latter (SCj) and the location of each associated antenna Aj (and in particular the distance dj separating it from an associated opening Oj) are preferably adapted to the diagram. radiation of each opening Oj and a predefined impedance.

It will also be noted that the device D may comprise at least one electrical circuit CE adapted to supply electrical signals to at least one antenna Aj and / or to receive electrical signals originating from at least one antenna Aj. This is particularly the case in the example of Figures 1 and 2.

For example, this electrical circuit CE may be clean in emission to combine in a chosen way the radiation patterns of the antennas Aj, and in reception to interpret and process in a chosen way the electrical signals coming from the antennas Aj, in order to perform selected functions. For this purpose, the electrical circuit CE may, for example, be able to control the respective amplitudes and / or the respective phases of the electrical signals that are derived from the antennas Aj or to the antennas Aj.

It will be noted that the aforementioned functions may, for example, be a radiocommunication function and a direction-finding function. The use of several antennas Aj can indeed make it possible to combine the direction-finding function and the radiocommunication function, in order to simultaneously exchange messages between vehicles or between a vehicle and an infrastructure (for example of the Car2X type) and determination of the arrival angles of these messages.

FIG. 3 is an example of an overall radiation pattern obtained in azimuth or in the horizontal plane with an example of device D of the type of that illustrated in FIGS. 1 and 2. This global diagram corresponds to a radiocommunication function . As can be seen, the device D makes it possible here to obtain a better gain towards the front of the vehicle (0 °), a smaller gain towards the rear of the vehicle (180 °), and a small gain on the sides of the vehicle (90 ° and 270 °). Directionality and sensitivity in dynamics can, for example, be chosen according to the speed of the vehicle and / or the environment (urban, tunnel, rural, mountain).

FIG. 4 schematically illustrates an example of an evolution of the amplitudes of the electrical signals respectively provided by the antennas A1 to A4 of the device D of FIGS. 1 and 2, as a function of the azimuth angle of arrival of an electromagnetic wave. . The curve c1 represents the evolution, as a function of the azimuth angle of arrival of an electromagnetic wave, of the amplitude of the electrical signals supplied by the antenna A1 from the electromagnetic waves received at the front of the vehicle ( centered on the azimuth 0 °), via the openire 01. The curve c2 represents the evolution, as a function of the azimuthal angle of arrival of an electromagnetic wave, of the amplitude of the electrical signals provided by the antenna A3 from the electromagnetic waves received at the rear of the vehicle (centered on the azimuth 180 °), via the opening 03. The curve c3 represents the evolution, as a function of the azimuthal angle of arrival of an electromagnetic wave, the amplitude of the electrical signals supplied by the antenna A2 from the electromagnetic waves received on the left side of the vehicle (centered on the 90 ° azimuth), via the aperture 02. The curve c 4 shows the evolution, as a function of the azimuthal angle of arrival of an electromagnetic wave, of the amplitude of the electrical signals supplied by the antenna A4 from the electromagnetic waves received on the right side of the vehicle (centered on the 270 ° azimuth), via aperture 04. This global diagram corresponds to a direction-finding function. Indeed, the amplitudes provided by each antenna Aj as a function of the azimuthal angle of arrival of an electromagnetic wave make it possible, by a post-treatment of the electric circuit CE, to obtain the arrival angle of this electromagnetic wave.

Note that an electrical circuit CE may optionally comprise at least one antenna Aj (as in the examples of Figures 2 and 3). In this case the antennas Aj may, for example, be screen printed on a printed circuit board or integrated circuit.

It will also be noted that an electrical circuit CE may be installed at a location chosen from inside the cavity CS (as in the example of FIGS. 1 and 2), the outside of the cavity CS, and the interior and the outside of the cavity CS (that is to say, extending partly inside and partly outside).

It will also be noted that the walls Pk and PLj of the structure SD may possibly delimit a housing or chassis of equipment providing at least one function, such as for example an automotive electronic computer having a radiocommunication function.

It will also be noted that the cavity CS may be at least partially filled with a non-conductive material, such as for example air.

It will also be noted that the openings Oj may be of any shape and may have orientations which are independent of each other and each function of the polarization of the electromagnetic waves received and / or transmitted. Therefore, the orientations of the openings Oj (with respect to the side walls PLj) may be identical or different from each other.

It will also be noted that the openings Oj may have shapes that are identical or different from each other. In the example shown non-limitatively in FIGS. 1 and 2, the four openings Oj have the same rectangular shape. But their shape could be round or elliptical or triangular or hexagonal, or even non-geometric.

It will also be noted that the respective positions of the openings Oj are independent of one another and can be located on any part of a wall Pk or PLj.

It will also be noted that each antenna Aj may operate either in transmission (for radiating into the cavity CS), or in reception, or in transmission and reception. Furthermore, each antenna Aj can participate in an antennal system of any type, including monopole type or dipole type. In addition, the different antennas Aj can be of the same or different types, and can be optimized for one or more different frequencies. The type of each antenna Aj is chosen according to the characteristics it offers, and in particular its electrical characteristics (input impedance), and its coupling with each associated aperture Oj.

It will also be noted that the device D may comprise a conductive flat surface secured to a wall of the structure SD which is not a wall provided with an opening Oj. This conductive flat surface may optionally comprise this wall without opening. Such a conductive flat surface may, for example, allow, by principle of symmetry or theory of images, to realize only half of the external structure of the cavity CS (it is thus possible to manufacture a dipole type antenna system from a monopoly type). In this case, it constitutes a plan of mass.

But the SD structure (and thus the CS cavity) could be associated with a flat non-conductive surface (such as a roof (or roof)), but in this case the bottom wall P1 must be conductive. By way of nonlimiting example, a device D may, for example, be part of a component of a vehicle chosen from at least the roof (or roof) and the lower part of the body structure. Here we mean by "being part" the fact of being solidarized on or under a constituent or in a constituent.

But a device D can also be installed inside the vehicle (or more generally system), for example in the engine compartment or the passenger compartment. This allows it to be installed close to an on-board equipment to form a receiver for the latter when it is responsible for providing electrical signals resulting from a conversion of electromagnetic waves received from at least other on-board equipment, and / or an emitter when it is responsible for converting the electrical signals it supplies to it into electromagnetic waves intended to be transmitted to at least one other on-board equipment (possibly temporarily, such as for example a mobile phone) .

Note also that a system, such as a vehicle, may include several devices D installed in different places and possibly associated with different functions.

It will also be noted that a device D may possibly interact with other devices or radiocommunication systems, for example by accommodating it at least partially on a wall Pk partially delimiting its cavity CS. It can also be integrated and used in a larger radiocommunication device or system. Furthermore, in order to improve the transmission and / or reception and / or aerodynamic performance and / or the aesthetics, the device D may optionally comprise a hull.

Claims (10)

1. Radio transmission and / or reception device (D) adapted to equip a system, characterized in that it comprises a closed structure (SD) and comprising i) walls (Pk, PLj) conducting and defining a cavity (CS), some of these walls (PLj) each comprising at least one aperture (Oj) having its own radiation pattern in space, and ii) at least one conductive inner wall (Pim) and subdividing said cavity (CS) in sub cavities (SCj) each associated with at least one of said openings (Oj), so that the latter (Oj) are independent of one another, and each housing at least one antenna (Aj) capable of converting electromagnetic waves passing through each opening (Oj) associated with its sub cavity (SCj) into electrical signals or electrical signals into electromagnetic waves adapted to pass through each opening (Oj) associated with its sub cavity (SCj). 2. Device according to claim 1, characterized in that in each sub cavity (SCj) dimensions of the latter (SCj) and a location of each antenna (Aj) associated are adapted to said radiation pattern of each opening (Oj) associated and a predefined impedance. 3. Device according to one of claims 1 and 2, characterized in that it comprises at least one electrical circuit (CE) adapted to supply electrical signals at least one antenna (Aj) and / or to receive electrical signals from at least one antenna (Aj). 4. Device according to claim 3, characterized in that said electric circuit (CE) is clean in emission to combine in a chosen way said radiation patterns of said openings (Oj), and in reception to interpret and treat in a chosen manner said electrical signals from said antennas (Aj), in order to perform selected functions. 5. Device according to claim 4, characterized in that said electrical circuit (CE) is adapted to control respective amplitudes and / or respective phases of said electrical signals from said antennas (Aj) or for said antennas (Aj). 6. Device according to one of claims 4 and 5, characterized in that said functions are selected from a group comprising a radiocommunication function and a direction-finding function. 7. Device according to one of claims 3 to 6, characterized in that said electrical circuit (CE) comprises at least one antenna (Aj). 8. Device according to one of claims 1 to 7, characterized in that it comprises a conductive flat surface secured to a wall (Pk) of the structure (SD) which is not a wall (PLj) provided with opening (Oj). Vehicle, characterized in that it comprises at least one radio transmission and / or reception device (D) according to one of the preceding claims. 10. Vehicle according to claim 9, characterized in that it is automotive type.