IT202100000887A1 - BEAMING ANTENNA, AND VEHICLE INCLUDING SUCH BEAMING ANTENNA - Google Patents

Description

DESCRIPTION of the industrial invention entitled:

"Directive antenna, and vehicle including such a directing antenna?

The present invention relates generally to a directive antenna, in particular for a vehicle, and to a vehicle including such a directive antenna.

The directional antenna according to the present invention ? especially suitable for use in vehicles, in particular to create communications of the V2X (Vehicle to Everything) type, preferably operating at frequencies around the 5.9Ghz, and will come? described below with reference to these applications without intending to limit their possible fields of application in any way.

As is known, in recent years we have been witnessing the marketing of vehicles that are increasingly? connected that integrate many services ranging from entertainment, for example radio and/or television, to driving assistance, typically via satellite navigators.

In this regard, in the field of telecommunications, with regard to vehicles, communication between vehicles is indicated with V2V (Vehicle to Vehicle), with V2I (Vehicle to Infrastructure) the communication between vehicles and infrastructures, and with V2P (Vehicle to Pedestrian) the communication between vehicles and pedestrians, and the acronym V2X means the communication between a vehicle and everything? what can? be relevant.

For this type of V2X communications, which can take place according to different standards (IEEE802.11p or CV2X), ? A frequency band around 5.9GHz has been allocated internationally with small differences depending on the regulatory body.

Consequently, it is therefore necessary to install antennas capable of operating at this frequency on modern vehicles.

Furthermore, given the possible use of V2X communications for applications also related to security, ? It is often necessary that the antennas on the vehicle have a coverage range as close as possible. as broad and appropriate as possible.

This coverage can be obtained both with a single antenna and by placing more? antennas in different positions of the vehicle. In fact, since the vehicle itself is mainly composed of metal parts which by their nature interact with the electromagnetic waves emitted by the antenna, depending on the position of an antenna, the radiation diagram can be differently deformed.

For example, depending on the curvature of the roof, an antenna positioned towards the rear of a car can not be able to radiate electromagnetic power towards the front of the car itself and to compensate for this effect? it is often necessary to insert a second antenna on the front of the car, for example near the rear-view mirrors.

To make more efficient antennas positioned in different points of the vehicle, ? possible to manipulate the radiation diagram of the same to avoid dispersing electromagnetic power in directions of no interest, or, in the case of an antenna installed inside the car in positions such as for example the rear view mirror, to ensure that the electromagnetic field towards the outside of the vehicle (forwards and towards the sides) where ? more probable there are devices with which to exchange communications, and not towards its occupants (reverse).

In this regard, there are antennas on the market which, in order to obtain the desired deformation of the radiation pattern, use a single radiating element combined with the directing effect of a screen of conductive material placed at a controlled distance from the radiating element itself.

The solutions known to date, while allowing appreciable results to be obtained, are susceptible to further improvements.

For example, the use of pi? antennas installed in different positions of a vehicle negatively affect production and installation costs.

On the other hand, an antenna coupled to a screen has a non-optimal control of the radiation pattern, in particular for what? which concerns the coverage of the intermediate angles transversal to the ideal axis that unites the direction of the maximum radiation to the direction of the minimum.

Therefore, the main purpose of the present invention ? that of proposing a directive antenna, in particular for communications of the V2X type, which with respect to known solutions allows to improve the control of the radiation pattern and is easy to produce.

Within this main scope, another scope of the present invention is that of providing a directive antenna which allows to guarantee a greater bandwidth with respect to known solutions, in particular with respect to those using a shielded antenna.

A further object of the present invention ? is to provide a directive antenna solution that is easy to implement and at relatively low cost, and that can be easily installed in the most? various types of vehicles both of the road type, such as for example cars, buses, commercial vehicles of various types, and of the railway type, such as for example trams, trains, etc.

This main purpose, as well as? the aforementioned further objects and others which will become clearer from the following description are achieved by a directional antenna the characteristics of which are defined in claim 1.

This main purpose, as well as? the aforementioned further objects are also achieved by a vehicle characterized in that it comprises at least one directional antenna as described below, and in particular as better defined by the appended claims.

Particular embodiments form the subject of the dependent claims, the content of which? to be understood as an integral part of this description.

Further characteristics and advantages of the invention will appear from the detailed description which follows, carried out purely by way of non-limiting example, with reference to the attached drawings, in which:

Figure 1 schematically illustrates a possible embodiment of a directional antenna according to the present invention;

Figure 2 schematically illustrates a possible variant embodiment of the antenna of Figure 1;

figures 3 and 4 schematically illustrate another possible embodiment of a directional antenna according to the present invention;

Figure 5 schematically illustrates a further embodiment of a directional antenna according to the present invention;

Figure 6 illustrates the horizontal radiation diagram obtained using the antenna of Figures 3 and 4;

figure 7 illustrates the vertical radiation diagram obtained using the antenna of figures 3 and 4;

figure 8 illustrates the reflection coefficient obtained using the antenna of figures 3 and 4;

Figure 9 illustrates a possible horizontal beam angle ? obtainable using a directive antenna according to the invention positioned on the front of a vehicle;

Figure 10 illustrates a possible vertical beam angle ? obtainable using a directional antenna according to the invention positioned on the front of a vehicle.

It should be noted that in the detailed description that follows, identical or similar components, from a structural and/or functional point of view, may have the same or different reference numerals, regardless of whether they are shown in different embodiments of the present invention or in distinct parts.

It should also be noted that, in order to clearly and concisely describe the present invention, the drawings may not necessarily be to scale and some features of the disclosure may be shown in somewhat schematic form.

In addition, when the term "adapted" or "arranged" or "configured" or "shaped" or a similar term is used herein, referring to any component as a whole, or to any part of a component or a combination of components , it is to be understood that it means and correspondingly includes the structure and/or configuration and/or shape and/or positioning.

In addition, when the term "substantial" or "substantially" is used herein, it is to be understood as including an actual variation of more than one? 5% or less compared to what is indicated as the reference value or position, and when the terms ?transversal? or ?transversely? used herein are to be understood as including a direction not parallel to the reference part(s) or direction(s)/axis to which they refer, and perpendicularity? ? to be considered a specific case of transversal direction.

Finally, in the description and in the following claims, the ordinal numerals first, second, et cetera, will be used for reasons of illustrative clarity and in no way are to be understood as limiting for any reason whatsoever; in particular, the indication for example of a "first value..." or ?first distance? does not necessarily imply the presence or the pressing requirement that there is a further "second distance", or a ?second value? or vice versa, unless such presence is clearly evident for the correct functioning of the described embodiments, n? that the order should be exactly in the sequence described with reference to the illustrated exemplary embodiments.

Figures 1-5 schematically illustrate a possible embodiment of a directional antenna according to the invention, globally indicated by the reference number 100.

The antenna 100 according to the invention comprises a plurality of radiating elements, that is to say at least two, and a power circuit that ? connected to the radiating elements and ? adapted to suitably supply them with a supply signal to be radiated.

In particular, according to the modalities? realizations that will be more? in detail from the following description, said first and second radiating elements and said power supply circuit are configured and operatively connected to each other so as to generate a combined radiation pattern which, on a horizontal plane, has a signal reduction in a preselected direction equal substantially at a quarter of a turn angle and an increase distributed in a substantially uniform way in the remaining three quarters of a turn angle.

In practice, the antenna 100 according to the invention allows, once the directions where the maximum and minimum of the radiated signal are desired, for example forward and respectively behind relative to a vehicle on which the antenna 100 is positioned. installed, to widen as much as the pi? possible the beam radiated towards the intermediate directions.

Pi? in detail, as illustrated for example in the embodiments of figures 1, 3, 4 and 5, the antenna 100 comprises at least:

- a first radiating element 1 and a second radiating element 2 arranged spaced apart from each other at a predetermined first distance D1; and

- a circuit or power supply network 5 which ? connected to and ? adapted to supply said first and second radiating elements 1, 2 with a supply signal to be radiated Si.

In particular, the power supply circuit 5 ? configured so that the signal to be radiated input to the first radiating element 1 is out of phase in time by a first predefined value ?? with respect to the same signal to be radiated fed into the input of the second radiating element 2.

In a possible embodiment of the directional antenna 100 according to the invention, the power supply circuit 5 ? configured so that the input signal supplied to the first radiating element 1 is out of phase in time with respect to the input signal fed to the second radiating element 2 by a first value between thirty and one hundred and twenty sexagesimal degrees,

In particular, according to a possible embodiment, the power supply circuit 5 is conveniently configured so that the input signal fed to the first radiating element 1 is out of phase with respect to the input signal fed to the second radiating element 2 by a first value between fifty and seventy sexagesimal degrees, preferably equal to sixty sexagesimal.

Usefully, according to a possible embodiment illustrated in the figures, the power supply circuit 5 comprises at least one conductor element 5a having a first end 5b connected to the first radiating element 1 and a second end 5c connected to the second radiating element 2, called at least one element conductor 5a having, with reference to the nominal operating frequency of the antenna 100, a predefined electrical length ?d? measured between said first and second extremes 5b and 5c.

In practice, the power supply circuit 5 transports the electromagnetic waves in input/output to the connection 6, for example from/to the electronics of a vehicle on which the antenna 100 is? installed, indicated in figures 9 and 10 by the reference number 200. In particular, in the case of a wave coming from the input 6 of the antenna 100 and which travels through the power supply network 5, thanks to the combination of the physical distance D1 suitably sized between the two radiating elements 1 and 2 and the configuration of the power supply circuit 5, and in particular of its part 5a between the two radiating elements 1 and 2, the transmitted wave will reach first to the radiant element pi? nearby, that is to say, the first element radiating 1 , and subsequently to the pi? distant, i.e. the second radiating element 2, with a phase difference defined by the following equation:

in which, ?? ? the phase difference between the signal of the transported wave fed to the input of the first radiating element 1 and the signal of the same wave fed to the input of the second radiating element 2, ?d? ? the electrical length of the part of the network or power supply circuit 5 included between the two ends connected respectively to the first and second radiating elements 1 and 2, and Alt ? the wavelength of the electromagnetic wave inside the power supply circuit 5.

In one possible embodiment, the predefined electrical length ?d? ? between one fifth and three quarters of a wave of the Si signal carried by circuit 5.

Pi? in particular, according to a possible embodiment, the predefined electrical length ?d? ? between two fifths of a wave and three fifths of a wave, more? preferably ? equal to a half wave.

In the embodiments illustrated in figures 3-4 and 5, the conductor element 5a is formed by a broken line having three substantially rectilinear sections which form an overall U- or C-shaped path, in which the electrical distance ? substantially given by the sum of the electrical lengths of the three straight sections of, 62, d3.

In practice, by imposing a different phase on the radiating elements 1 and 2, a desired deformation of the radiation pattern is obtained, as illustrated for example in figures 7 and 8, which can be suitably calibrated according to needs.

Clearly, the power supply circuit 5, and in particular its part 5a which interconnects the two radiating elements 1 and 2, can be configured differently so as to similarly obtain the same technical results in terms of modification of the radiation diagram of the antenna 100.

For example, in a possible embodiment, the power supply circuit 5 comprises at least one conductor element 5a having a first end 5b connected to the first radiating element 1, a second end 5c connected to the second radiating element 2, and a support element, for example, a strip made of dielectric material, which ? mechanically connected at least to said conductive element 5a and acts as a mechanical support for the same, also contributing to obtain the desired phase shift ??.

This support element can be shaped for example by replicating the shape and following the physical path of the power supply circuit 5 or only of its part 5a, or even have a different shape as long as? suitable for supporting the circuit 5 itself, and in particular its part 5a, and for contributing to the achievement of the desired phase shift ??.

For example, if the signal power circuit 5 ? made through a microstrip, the support element can? be constituted by a body made of dielectric material which replicates at least in part the path of the microstrip, in particular for what? which concerns at least part 5a. If, on the other hand, the supply circuit of the signal 5, and in particular at least its part 5a, is made, for example, through a coaxial cable, then the cable can? also be mechanically released from the support that holds the radiating elements and have the extremes 5b and 5c as the only points of contact.

In a further possible embodiment of the directional antenna 100 according to the invention, the power supply circuit 5 comprises at least one component with lumped constants arranged between said first and second radiating elements 1 and 2. This component, schematically illustrated in figure 2 from the dotted wrapper 30, can it? be constituted, for example, by a capacitor or an inductance.

In particular, according to this embodiment the supply circuit 5, or at least the part thereof interposed between and interconnecting the two radiating elements 1 and 2, can include or consist of a ?T? or to ?pi? combinations of inductors or capacitors, which achieve the desired phase shift, without having to resort to a binding physical distance between the input ports of the radiating elements 1 and 2. In this way, there is a greater degree of freedom? about the spacing between the same elements radiating 1 and 2, which can? be cos? chosen to a less dependent extent on the physical architecture of the power supply network 5 itself.

In a possible embodiment, and as illustrated in the examples of figures 1 -5, the directional antenna 100 further comprises a support element 3 on which said first and second radiating elements 1 and 2 are at least partially arranged or to which they are connected and the power circuit 5.

In the illustrated examples, this support element 3 has a substantially planar development and the radiating elements 1 and 2 and the power supply circuit 5 can be arranged on mutually opposite faces of this planar element 3, as in the embodiment illustrated in Figures 3 and 4, or on the same face as illustrated in the embodiments of figures 1, 2 and 5.

In one possible embodiment, one or more? of said power supply circuit 5, and first and second radiating elements 1 and 2, preferably each of them, comprises a respective metal conductor connected to a ground element fixed to the support element 3 or constituted by the support element 3 itself.

In particular, depending on the applications, this mass element can? therefore be constituted by the same support element 3 which in this case ? substantially made of conductive material.

Alternatively, the support element 3 can? be made of dielectric material and the mass element comprises at least one conductive surface, which at least partially covers one face of the support element 3 (see figure 5), or ? arranged on both faces of the support element 3 so as to cover them at least partially (see figures 3 and 4).

In the illustrated embodiments, each mass element ? consisting of a copper conductor lamina having a substantially planar development and indicated in figures 3-5 by the reference number 4.

This element of mass 4 ? sized so as to have a surface suitably larger than that of the radiating elements so as to modify, typically lower or raise, the elevation of the maximum of the radiated signal illustrated in figure 7.

In particular, in the embodiment of figures 3 and 4, the radiating elements 1 are made with PCB (Printed Circuit Board) technology and consist, for example, of traces of copper deposited on a dielectric support 7.

The shape and dimensions of the copper traces forming the two radiating elements 1 and 2 are selected to obtain a resonance of the antenna 100 around the operating frequency, for example around 5.9GHz. Furthermore, to improve the adaptation of the antenna, in this embodiment ? provided for each radiating element 1 and 2, a corresponding branch 8 and 9 respectively, the two branches 8 and 9 being connected to a common ground element 4.

In turn, the power supply circuit 5 ? in this example made on the opposite face of the support element 3 with respect to the radiating elements 1 and 2, and can? also be made with PCB technology. For example, circuit 5 can? be composed of a waveguide known as a microstrip. This waveguide? formed by a copper trace and a mass element divided by a dielectric thickness. The width of the copper trace ? suitably sized to have for example a characteristic impedance of the microstrip equal to 50?. Narrowings or widenings 11 of the microstrip can be made to improve the overall adaptation of the antenna 100. To fix the radiating elements 1 and 2 to the support element 3, holes 10 can be made in which the PCBs of the radiating elements are inserted 1 and 2 to be subsequently connected by welding to the power supply circuit 5.

In the embodiment of figure 5, the radiating elements 1 and 2 are instead made using folded laminations. Compared to PCB technology, this solution allows for example to exploit more? the available space is efficient by developing the radiant elements three-dimensionally, and in many cases it allows to optimize, or reduce, the production cost of the radiant elements themselves. In this case, the power supply circuit 5 ? made from the same side as the radiating elements 1 and 2 again using for example a microstrip. To obtain a better adaptation of the antenna 100, two points of connection to the ground plane 4 have been added to the radiating elements 1 and 2, indicated by the reference numbers 12 and 13 respectively.

Clearly, depending on the application requirements, in the antenna 100 according to the invention ? It is possible to use differently configured heating elements, as well as a greater number of heating elements.

For example, as schematically illustrated in the embodiment of figure 2, ? the use of at least a third radiating element 20 arranged spaced apart from the first radiating element 1 by a predetermined second distance D2, and from the second radiating element 2 by a predetermined third distance D3 is envisaged. This third radiating element 20 can? be suitably arranged to create a triangular configuration, as illustrated for example in figure 2, or can? be arranged aligned with the two radiating elements 1 and 2 so as to form a linear configuration.

In turn, the power supply circuit 5 ? connected to and ? adapted to also supply the third radiating element 20 with the supply signal Si to be radiated. In particular, the power supply circuit 5 ? configured in such a way that the signal to be radiated input to the third radiating element 20 is phase shifted in time by a second predefined value with respect to the input signal fed to the first radiating element 1 and by a third predefined value with respect to the input signal fed to the second radiating element 2.

What previously described in relation to the embodiments with only the two radiating elements 1 and 2, ? equally applicable therein in the presence of the third radiating element 20, as also for any further radiating element.

In particular, the values indicated for the electrical distance ?d? and the phase shift between the first radiating element 1 and the second radiating element 2, are applicable to each pair of radiating elements, and therefore in the case of the third radiating element 20 to the first-third radiating element pair 1 and 20, and respectively to the second copy -third elements radiating 2 and 20.

Also, in the examples shown, each of the physical distances D1 , D2 and D3 between element cups, ? illustrated measured between two surfaces pi? close and facing each other; alternately, ? It is possible to define each distance in another way, for example in the case of radiating elements of symmetrical shape, calculating it as the distance between the respective axes of symmetry, or in another way still suitable for sizing the antenna according to the invention.

In a further possible embodiment, the antenna 100 comprises for example a casing of dielectric material, schematically illustrated only in figure 2 by the reference number 50. This casing 50 allows to further deform the overall radiation pattern in a controlled manner.

Yes ? in practice it has been ascertained that the directional antenna 100 according to the invention allows to fulfill the set aim since it allows to obtain a decidedly improved control of the radiation diagram compared to known solutions, and in particular to expand the azimuthal angle of coverage which with the known solutions does not reach three quarters of the round angle, obtaining a greater coverage of the intermediate angles transversal to the ideal axis which joins the direction of the maximum radiation to the direction of the minimum.

An example of this? illustrated in figures 6, 7 and 8, where the results shown are obtained by means of the embodiment of the antenna 100 illustrated in figures 3 and 4. In particular, these results have been obtained by imposing a phase shift of 60? and a physical distance D1 of about 12.7mm, consequently dimensioning the length of the power supply circuit 5 according to the previously indicated equation. In particular, figures 6 and 7 refer respectively to the irradiation diagram on the horizontal and vertical plane; as horizontal and vertical planes are meant for example those illustrated in figures 9 and 10 where the sectors, angle ? for the horizontal and angle? for the vertical, where most of the power is radiated. In figure 8 ? also shown is the reflection coefficient obtained for the antenna 100 taken for example.

L?antenna 100 so? conceived also allows to guarantee a greater bandwidth thanks to the particular feeding technique, allowing, if necessary, to use the same antenna also for transmissions in bands close to that allocated to V2X communication, such as for example the WiFi band.

To get there? , as previously illustrated, components are used that are easy to make and assemble at low cost, which allow the operation of the antenna itself to be suitably calibrated, in particular by suitably playing on the mutual distance between the radiating elements and on the electrical length of the circuit part or supply network 5 which interconnects them and feeds them with the signal to be radiated.

With further advantage, the antenna 100 according to the invention can be used in principle in any type of vehicle, both road and rail, and pu? be easily installed both on new vehicles and, if desired, on vehicles already? In circulation. Therefore, a further object of the present invention relates to a vehicle characterized in that it comprises at least one directional antenna 100 as previously described, and more particularly defined in the appended claims.

Of course, the principle of the invention remaining the same, the embodiments and the details of construction can be widely varied with respect to what ? been described and illustrated purely by way of preferred but non-limiting examples, without thereby departing from the scope of protection of the present invention as defined in particular by the attached claims. For example, the previously described embodiments can be combined with each other, even partially, by selecting for this purpose one or more? of the features described with reference to a possible embodiment and using, where useful or possible, each feature selected in one of the other embodiments described. For example, the device 30 or the casing 50 could be used in all or only in some of the illustrated embodiments. The shape of the described components or part of them can? be suitably modified as long as? in a manner compatible with the purpose and functionality? whereby such components have been devised within the scope of the present invention. For example, the radiating elements 1, 2 and 20, and/or the power supply circuit 5 or part thereof can be made by metallization on dielectric materials, for example plastic materials; these radiating elements can be shaped differently from what is illustrated in the examples and can be arranged in a position other than the essentially vertical one illustrated in the accompanying figures; the power circuit 5 can? have at least in part a curvilinear or mixed shape; can you? be a single element of mass 4 for all the radiating elements, or can? one ground element may be used for each radiating element used, and the ground elements may or may not be electrically connected to each other; each mass element pu? be made up of an element not necessarily having a planar development; the casing of dielectric material 50 pu? be replaced by bulky mechanical components, i.e. of dimensions comparable to or greater than those of the radiating elements; et cetera.

Claims (10)

1. Directive antenna (100), characterized by the fact that it includes at least: - a first radiating element (1) and a second radiating element (2) arranged spaced apart from each other at a predetermined first distance (D1); - a power supply circuit (5) which ? connected to and ? adapted to supply said first and second radiating elements (1, 2) with a supply signal to be radiated, wherein said supply circuit (5) comprises at least one conducting element (5a) having a first end (5b) connected to the first element radiating element (1) and a second extreme (5c) connected to the second radiating element (2), called at least one conducting element (5a) having, with reference to the nominal operating frequency of the antenna (100), a predefined electrical length (d) measured between said first and second extremes (5b, 5c) that ? comprised between a fifth wave and three quarters of a wave, said supply circuit (5) being configured in such a way that the input signal supplied to the first radiating element (1) is? phase shifted in time with respect to the input signal supplied to the second radiating element (2) by a first value between thirty and one hundred and twenty sexagesimal degrees. 2. Directive antenna (100) according to claim 1, wherein said first and second radiating elements (1, 2) and said power supply circuit (5) are configured and operatively connected to each other so as to generate a combined radiation pattern which , on a horizontal plane, has a signal reduction in a preselected direction substantially equal to a quarter of a turn angle and an increase distributed in a substantially uniform manner in the remaining three quarters of a turn angle. 3. Directive antenna (100), according to claim 1 or 2, wherein said power supply circuit (5) comprises a support element mechanically connected at least to said conductor element (5a). 4. Directive antenna (100) according to one or more? of the preceding claims wherein said power supply circuit (5) comprises at least one lumped constant component (30) arranged between said first and second radiating elements (1, 2). 5. Directive antenna (100) according to one or more? of the preceding claims wherein said predefined electrical length (d) ? between two fifths of a wave and three fifths of a wave. 6. Directive antenna (100) according to one or more? of the preceding claims wherein said power supply circuit (5) ? configured so that the input signal supplied to the first radiating element (1) ? phase shifted in time with respect to the signal supplied at the input to the second radiating element (2) by a first value comprised between fifty and seventy sexagesimal degrees. 7. Directive antenna (100) according to one or more? of the preceding claims, further comprising at least one support element (3) on which said first and second radiating elements (1, 2) and said supply circuit (5) are at least partially disposed or connected to. The directive antenna (100) according to claim 7, wherein one or more? of said supply circuit (5), first and second radiating elements (1, 2) comprise a metal conductor connected to a ground element (4) fixed to the support element (3) or constituted by the support element (3 ) same. 9. Directive antenna (100) according to one or more? of the preceding claims, comprising at least a third radiating element (20) spaced apart from said first radiating element (1) at a predetermined second distance (D2) and from said second radiating element (2) at a predetermined third distance (D3), and in which said supply circuit (5) ? connected to and ? adapted to supply said third radiating element (20) with said supply signal to be radiated, in which said supply circuit (5) ? configured so that the signal to be radiated fed into the input of the third radiant element (20) is phase shifted in time by a second predefined value with respect to the signal fed into the input of the first radiant element (1) and by a third predefined value with respect to the fed signal at the entrance to the second radiating element (2). 10. Vehicle characterized in that it comprises at least one directional antenna (100) according to one or more of the previous claims.