Patent Application
20250239785
The present disclosure relates to an antenna for motor vehicles, and to a motor vehicle comprising such an antenna.
The antenna according to the disclosure is especially suited for use in automobiles, for example mounted on the roof of a car, and will be described herein with reference to such use without limiting its possible applications to other types of motor vehicles, such as buses, trucks, commercial vehicles, et cetera.
As is well known, antennas intended to be mounted on the roof or another external surface of a motor vehicle essentially comprise a functional part, consisting of a plurality of suitably configured and assembled components that are suitable for mounting and operating the antenna, and a cover or dome whose purpose is to contain the various functional components of the antenna and to ensure, where possible, that the vehicle retains a suitable aerodynamic appearance and efficiency once the antenna has been installed.
Normally, the functional part of the antennas used comprises a plurality of radiating elements that can transceive data and signals of different types according to various standards and related frequency ranges that have been introduced over the years.
Although the antennas currently on the market can perform the functions for which they are designed, there are some aspects that could be improved.
In particular, the presence of several radiating elements inevitably placed close together in the cramped space offered by the cover, leads to problems concerning the actual quality of the signals due to the possible coupling between the signals afferent to two or more radiating elements and interfering with each other.
Therefore, there is desire and room for improvements in existing antennas.
The present disclosure provides an antenna for a motor vehicle, comprising at least:
According to some embodiments, the antenna according to the present disclosure may comprise one or more of the following features, which may be combined in any technical feasible combination:
The present disclosure provides also a motor vehicle comprising at least one antenna as above defined.
Further features and advantages of the disclosure will appear from the following detailed description, carried out by way of non-limiting example only, with reference to the accompanying drawings, in which
It should be noted that in the following detailed description, identical or similar components, from a structural and/or functional point of view, may have the same or different reference numbers, regardless of whether they are shown in different embodiments of the present disclosure or in separate parts.
It should also be noted that, in order to clearly and concisely describe the present disclosure, the drawings may not be to scale and some features of the description may be shown in a somewhat schematic form.
Furthermore, when the term “adapted” 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 shall be understood to mean and include correspondingly the structure and/or configuration and/or shape and/or positioning.
In particular, when these terms refer to electronic hardware or software, they are to be understood as including electronic circuits or parts of electronic circuits, as well as software/firmware, such as algorithms, routines and programs in general, running and/or resident in any storage medium.
In addition, when the term “substantial” or “substantially” is used herein, it shall be construed as including unavoidable constructional/functional tolerances. In addition, when the term “substantial” or “substantially” is used herein, it shall be construed as including unavoidable mechanical/performance tolerances, or an actual variation of plus or minus 5% from the stated reference value, direction or position, and when the terms “transverse” or “transversely” are used herein, they are to be understood as including a direction not parallel to the reference part(s)/axis(s) to which they refer, and perpendicularity is to be regarded as a specific case of transverse direction.
Finally, in the following description and claims, the ordinal numerals first, second, et cetera, will be used for reasons of illustrative clarity and in no way should they be understood as limiting for any reason whatsoever, nor that the order should be exactly that in the sequence described with reference to the examplary embodiments described.
The antenna 100 according to the disclosure comprises at least:
For example, the second frequency band is higher than the first frequency band.
The non-resonant radiating element 10 has a high reactive component.
In particular, as known to those skilled in the art, a resonant radiating element is a radiating element whose input impedance has a reactive component that crosses zero at the center of the relevant transceiver frequency band, while a non-resonant one is a radiating element whose input impedance has a reactive component that is not zero and has a modulus substantially greater than the resistive component, e.g. about 5-6 times greater.
In particular, the second radiating element 20 comprises a first printed circuit board 22 which is arranged with one of its first end portions 23, i.e. at one of its lower ends, on the electronic circuit 5 and rises upwardly from it along a reference direction transversal to the electronic circuit 5, indicated in
For example, the reference direction X is a direction lying in a virtual plane transversal, and in particular perpendicular, to the electronic circuit 5.
For instance, when the electronic circuit 5 is arranged on the mounting base 1, e.g. in a substantially horizontal position, the reference direction or axis X extends along a substantially vertical direction.
An electrically conductive track 24 is arranged along the first printed circuit board 22.
The electrically conductive track 24 has one end 26 connected to the electronic circuit board 5 and runs on the first printed circuit board 22 along a substantially helical or serpentine path, up to a predetermined height H.
A series of appropriately metallised through holes, indicated in
In this way, the metallised holes 27 and the various strip sections together form the electrically conductive trace 24 that runs continuously along the helical or serpentine path, up to the height H.
In practice, as a whole, the conductive track 24 essentially behaves as if it were a conducting loop wrapped around the first printed circuit board 22.
The height H, measured e.g. from the surface of the first end portion 23 resting on the electronic circuit 5, is chosen so as to optimise the transceiving of the signals emitted in the second frequency band.
Usefully, the electronic circuit 5 is at least configured to distinctly process said first and second signals received from the first non-resonant radiating element 10 and the second radiating element 20, respectively.
In one possible embodiment, the electronic circuit 5 comprises or consists of at least one printed circuit board (hereinafter “second printed circuit board”) arranged on said mounting base 1, e.g. in a substantially horizontal position.
The mounting base 1 can be made in one or more pieces and in one or more materials suitably combined with each other.
For example, in the embodiment illustrated in
In practice, in this exemplary embodiment, the mounting base 1 has a shape, seen in plan view from above or below, configured like the base of an iron.
In one possible embodiment the body of the mounting base 1 has, for example in a substantially central area, i.e. the area in which the second printed circuit board forming or being part of the electronic circuit 5 is positioned, a compartment or housing space in which cables, various electronic components, etc. can be accommodated.
As illustrated in
During assembly, the cover 40 is mechanically coupled to the mounting base 1 so that at least the second printed circuit board forming or being part of the electronic circuit 5, as well as the two radiating elements 10 and 20, are housed in its cavity.
Clearly, depending on the applications, other components can be accommodated within the space offered by the cavity of the cover 40, e.g. gaskets, other signal-transmitting elements, etc.; for example, an additional component 7 configured for the reception of GPS signals is illustrated in
The mounting of the mounting base 1 on the roof or on a suitable mounting surface of a motor vehicle and the connection of the cover 40 to the same mounting base 1, are carried out in a manner known or readily available to a person skilled in the art, and in any event not relevant to the present disclosure, and therefore not described in detail herein.
According to a possible embodiment, the first non-resonant radiating element 10 is configured to receive and transmit towards the electronic circuit 5 analogue type signals, in particular first signals emitted in the FM (Frequency Modulation) frequency band, and the second radiating element 20 is configured to receive and transmit towards the electronic circuit 5 digital type second signals, in particular signals emitted in the DAB frequency band.
In the example illustrated, the second frequency band, e.g. the DAB frequency band, is the upper frequency band with respect to the lower first frequency band, e.g. the frequency band FM.
Conveniently, in one possible embodiment, the first non-resonant radiating element 10 is made of a single piece of metal material, e.g. tin-plated steel.
In particular, the first non-resonant radiating element 10 has an overall electrical length that is less than the operating wavelength for each frequency band, and particularly the band with the higher operating frequency (thus having shorter wavelength).
In particular, the first non-resonant radiating element 10 has an overall electrical length equal to or less than 10% of the wavelength at the center of the upper frequency band between the first and second frequency bands, preferably equal to or less than 5%, more preferably equal to or less than 3%.
This may contribute or render the radiating element 10 non-resonant.
As known, the electrical length of an element may be defined as its physical length in relation to the working wavelength.
If the first non-resonant radiating element 10 is formed by one section substantially straight section, then the electrical length has to be calculated based on the length of that section, measured along the centerline thereof.
If the first non-resonant radiating element 10 is formed by two or more sections, the electrical length has to be calculated by summing all lengths calculated along the centerline of each section.
For instance, in case of a curved section, the respective length can be calculated and summed up to the other sections once the curved section is considered straightened.
In the exemplary embodiment illustrated, the first non-resonant radiating element 10 comprises a shaped body which is configured to fill as much as possible the space dedicated to it and comprised between the cover 40, the printed circuit board forming or included in the electronic circuit 5, and the second radiating element 20.
According to a possible embodiment, illustrated in the example of
For example, the connection between the first non-resonant radiating element 10 and the electronic circuit 5 is made by means of one or more pins, e.g. two pins 13A and 13B as illustrated in
In a possible embodiment, with reference to a side view, the first non-resonant radiating element 10 is arranged with at least the first substantially planar portion 11 substantially aligned and in sequence with the second radiating element 20 along a direction joining the front edge 2 with the rear edge 3 of the mounting base 1.
In a possible embodiment, as illustrated in the example of
The capacitive cap 14 cooperates with the first portion 11 with planar development and allows the overall emissive capacity of the first non-resonant radiating element 10 to be optimised.
In particular, according to a possible embodiment, the second portion 14 comprises, with reference to a front view of the antenna 100 (i.e. view from the front edge 2 of the mounting base 1):
The second section 18, with reference to a side view of antenna 100, is inclined downwards proceeding from the rear edge 3 to the front edge 2 of mounting base 1.
According to this embodiment, the overall electrical length of the non-radiating element 10 is given by the sum of the electrical lengths of the sections 11, 15, 17, 18 and 19, for instance calculated along the center line of each section in a plane transversal to the plane where the electronic circuit 5 lies.
Such transversal plane can be for example a substantially vertical plane, e.g. the plane of the sheet of
At least one protective element 9 can be placed around the second portion 14 of the first radiating element, e.g. a sponge or a piece of self-adhesive foam.
Such a protective element 9 can also be arranged directly around the first circuit board 22 of the second radiating element 20.
In a possible embodiment, the electronic circuit 5 comprises a first filter stage, indicated in
In particular, according to a possible embodiment, the first filtering stage 50 comprises at least:
In practice, the two filters 50A and 50B are selective filters of the frequency bands of interest, e.g. FM or DAB, and are adaptive in that they are configured to compensate for the reactive part of the non-resonant radiating element 10 in the band of interest (FM/DAB) by adapting it as much as possible to the complex conjugate of the input impedance of the active stage 51.
The complex conjugate is an input impedance value that has a resistive part substantially equal to the resistive part of the first non-resonant radiating element 10, and a reactive part that is of equal modulus but opposite sign to the reactive part of the first non-resonant radiating element 10.
Furthermore, these filters can also raise the remaining purely resistive value of the antenna impedance to better match the input value of the active stage 51, and are purely reactive, i.e. they do not introduce losses and optimise the performance of the stages from a noise point of view.
In one possible embodiment, the active stage 51 comprises at least a first plurality of active stages operatively connected to the first filter 50A and arranged in sequence with each other, and a second plurality of active stages connected to the second filter 50B and arranged in sequence with each other.
In particular, in the exemplary embodiment illustrated in
The active stages of the first plurality are configured to have high input impedance, in particular to better match the impedance of the non-resonant radiating element 10.
In particular, at least the first stage of the first and second plurality of active stages is optimised with regard to noise performance, while the following stage(s) of the first and second plurality of active stages is/are configured at least to optimise the dynamics performance so as to achieve an adequate compromise between the two requirements.
Clearly, the number of stages of the first and second plurality of active stages can be varied appropriately.
In a possible embodiment, the second stage of filtering 52 comprises at least:
In practice, the third 52A filter and the fourth 52B filter are additional selective filters so that the respective signals are only allowed to pass in the band of interest (FM/DAB).
This makes it possible to reduce out-of-band noise and unwanted harmonics, e.g. upper harmonics or IM2 second-order intermodulation.
In a possible embodiment, the electronic circuit 5 further comprises a combiner, schematically represented in
In this way, the combiner 55 allows the unification of signals (each in its own frequency band) on a single coaxial output cable 56, optimising overall implementation costs.
Alternatively, signals for the first and second frequency bands can be routed along two separate cables without using the combiner 55.
In practice, it has been ascertained that the antenna 100 according to the disclosure adequately fulfils its intended purpose, as it has a structure which, compared to known solutions, allows the signals afferent to the two radiating elements 10 and 20 to be decoupled more effectively, making optimal use of the albeit limited space available within the cover 40.
In addition, the antenna 100 features a design that makes it suitable for use in new motor vehicles as well as for replacing antennas already installed on motor vehicles in use.
Of course, without prejudice to the principle of the disclosure, the forms of implementation and details of realisation may be widely varied with respect to what has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of protection of the present disclosure as defined by the appended claims, including any possible combination, even partial, of the embodiments described above.
For example, the non-resonant radiating element 10 can also receive signals in the AM frequency band. In this case, the AM signals can be processed by the electronic circuit 50 in parallel to the signals in the other frequency bands described above, e.g. by using low-pass filtering at the input and then amplifying the signals in parallel to the others, and then feeding the AM signals also into the combiner 55.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102024000000900 | Jan 2024 | IT | national |
