Antenna for motor vehicle and motor vehicle comprising such antenna

Abstract

The invention relates to an antenna for a motor vehicle and a motor vehicle comprising such an antenna. The antenna includes: a mounting base connected to a mounting surface of the motor vehicle; an electronic circuit disposed on the mounting base; a non-resonant radiating element that receives a first signal transmitted in a first frequency band by a device external to the antenna and transmits the first signal to the electronic circuit; and a second radiating element that receives a second signal transmitted by a device external to the antenna in a second frequency band different from the first frequency band and transmits the second signal to the electronic circuit. The second radiating element includes a first printed circuit board arranged with a first end portion thereof on the electronic circuit and rising upward therefrom. A conductive track is provided on the first printed circuit board that extends along a helical or serpentine path up to a predetermined height. The electronic circuit is configured to process a first signal and a second signal received from the first non-resonant radiating element and the second radiating element, respectively, in different ways.

Description

Field of the Invention

[0001] The present invention relates to an antenna for a motor vehicle and a motor vehicle including such an antenna.

[0002] The antenna according to the present invention is particularly suitable for automobiles, for example, suitable for being mounted on the roof of a vehicle, and will be described herein with reference to such a use, without limiting its possible application to other types of motor vehicles, such as buses, trucks, commercial vehicles, etc. Background Art

[0003] As is well known, an antenna intended to be mounted on the roof or another outer surface of a motor vehicle mainly includes a functional part, which is composed of a plurality of appropriately configured and assembled components suitable for mounting and operating the antenna, and a covering or dome-shaped part. The purpose of the covering or dome-shaped part is to accommodate various functional components of the antenna and, if possible, ensure that the vehicle maintains a suitable aerodynamic appearance and efficiency once the antenna is installed.

[0004] Generally, the functional part of the antenna used includes a plurality of radiating elements, which can transmit and receive different types of data and signals according to various standards and related frequency ranges promoted over the years.

[0005] Although the antennas currently on the market can perform the functions they are designed for, there are still some aspects that can be improved.

[0006] In particular, due to the possible coupling between the signals incoming to two or more radiating elements and their mutual interference, the presence of several radiating elements inevitably placed closely together in the narrow space provided by the covering can lead to problems related to the actual quality of the signals. Summary of the Invention

[0007] Therefore, an object of the present invention is to provide an antenna for a motor vehicle that can at least partially alleviate these problems.

[0008] This object and other objects that can be derived from the following description are achieved by an antenna for a motor vehicle, the features of which are defined in claim 1.

[0009] This object is also achieved by a motor vehicle according to claim 10.

[0010] Specific embodiments are the subject matter of the dependent claims, and the content of the subject matter of the dependent claims should be understood as an integral part of this specification. Brief Description of the Drawings

[0011] In the following detailed description, which is given by way of non - limiting example only with reference to the accompanying drawings, other features and advantages of the present invention will become apparent, in which:

[0012] Figure 1 is an exploded view illustrating a possible embodiment of an antenna according to the present invention;

[0013] Figure 2 is Figure 1 a front view of the antenna in;

[0014] Figure 3 is a block diagram schematically illustrating an electronic circuit used in the antenna according to the present invention. DETAILED DESCRIPTION

[0015] It should be noted that in the following detailed description, components that are the same or similar from a structural and / or functional perspective may have the same or different reference numerals, whether they are shown in different embodiments of the present invention or in separate parts.

[0016] It should also be noted that for the sake of clarity and conciseness in describing the present invention, the drawings may not be drawn to scale, and some of the features described may be shown in a slightly schematic form.

[0017] Furthermore, when the terms "adapted to" or "configured to" or "shaped to" or similar terms are used herein, it refers to any component as a whole or any part of a component or a combination of components, which should be understood to refer to structure and / or construction and / or shape and / or orientation and correspondingly include structure and / or construction and / or shape and / or orientation.

[0018] In particular, when these terms refer to electronic hardware or software, they should be understood to include electronic circuits or parts of electronic circuits, as well as software / firmware, such as algorithms, routines, and programs that typically run or reside in any storage medium.

[0019] In addition, when the terms "substantially" or "essentially" are used herein, they should be construed to include inevitable structural / functional tolerances. Additionally, when the terms "substantially" or "essentially" are used herein, they should be construed to include inevitable mechanical / performance tolerances, or an actual variation of plus or minus 5% with respect to the stated reference value, direction, or position, and when the terms "lateral" or "laterally" are used herein, they should be understood to include a direction that is not parallel to the reference component / axis to which it refers, and perpendicular should be regarded as a specific case of the lateral direction.

[0020] Finally, in the following description and claims, for reasons of clarity of illustration, ordinal numbers such as "first", "second", etc. will be used, and they should in no way be construed as limiting for any reason, nor should they be construed as meaning that the order should precisely be the order in which the exemplary embodiments described are referenced.

[0021] Figures 1 to 3 Illustrated is a possible embodiment of an antenna generally designated by reference numeral 100 in accordance with the present invention.

[0022] The antenna 100 according to the present invention at least comprises:

[0023] - A mounting base 1 which, when the antenna 100 is mounted, is intended to be coupled to a mounting surface of a motor vehicle, such as a roof of a motor vehicle.

[0024] - An electronic circuit 5 which is adapted to be disposed directly on the mounting base 1 or in a manner such that one or more other components are inserted between the electronic circuit 5 and the mounting base 1.

[0025] - At least one non-resonant radiating element designated by reference numeral 10, the at least one non-resonant radiating element being operatively connected to the electronic circuit 5 and configured to receive a first signal transmitted in a first frequency band by one or more devices external to the antenna 100 and send the first signal to the electronic circuit 5.

[0026] - A second radiating element 20 which is configured to receive a second signal transmitted in a second frequency band different from the first frequency band by one or more devices external to the antenna 100 and send the second signal to the electronic circuit 5.

[0027] For example, the second frequency band is higher than the first frequency band.

[0028] The non-resonant radiating element 10 has a high reactance component.

[0029] In particular, as is known to those skilled in the art, a resonant radiating element is a radiating element whose reactance component of the input impedance crosses zero at the center of the relevant transceiver frequency band, while a non-resonant radiating element is a radiating element whose reactance component of the input impedance is non-zero and has a modulus significantly greater than the resistance component, for example about 5 to 6 times the resistance component.

[0030] In particular, the second radiating element 20 includes a first printed circuit board 22 which is arranged on the electronic circuit 5 by means of one of its first end portions 23, i.e. at one of its lower end portions, at its lower end, and rises upward from the electronic circuit 5 along a reference direction transverse to the electronic circuit 5, the reference direction being indicated by an arrow X in Figure 1 and is indicated by an arrow X in

[0031] For example, the reference direction X is a direction lying in a virtual plane transverse to the electronic circuit 5 and in particular perpendicular to the electronic circuit 5.

[0032] For example, when the electronic circuit 5 is arranged on the mounting base 1 in a substantially horizontal position, for example, the reference direction or reference axis X extends along a substantially vertical direction.

[0033] Conductive tracks 24 are arranged along the first printed circuit board 22.

[0034] The conductive track 24 has an end 26 connected to the electronic circuit board 5 and extends along a substantially spiral or serpentine path on the first printed circuit board 22 up to a predetermined height H.

[0035] In Figure 1 a series of suitably metallized through-holes indicated by the reference numeral 27 in connect various conductor strip segments arranged on two opposite side portions of the first printed circuit board 22.

[0036] In this way, the metallized holes 27 and the various strip segments together form a conductive trace 24 which extends continuously along a spiral or serpentine path up to the height H.

[0037] In fact, as a whole, the conductive track 24 generally behaves as if it were a conductive loop wound around the first printed circuit board 22.

[0038] The height H, measured for example from the surface of the first end portion 23 resting on the electronic circuit 5, is selected so as to optimize the reception and transmission of the signals emitted in the second frequency band.

[0039] Advantageously, the electronic circuit 5 is at least configured to process the first signal and the second signal received respectively from the first non-resonant radiating element 10 and the second radiating element 20 in different ways.

[0040] In a possible embodiment, the electronic circuit 5 includes or consists of at least one printed circuit board (hereinafter referred to as "second printed circuit board") arranged in a substantially horizontal state on the mounting base 1, for example.

[0041] The mounting base 1 can be made of one or more components and one or more materials suitably combined with each other.

[0042] For example, in Figures 1 to 2 the illustrated embodiment, the mounting base 1 has a central portion made of metal on which the electronic circuit 5 is disposed and the remaining portion made of a plastic material, and the mounting base 1 has, for example, a front edge 2, a rear edge 3, and two side edges 4 that extend from the rear edge 3 and converge towards each other to form, for example, a front edge 2 having a pointed shape.

[0043] In fact, in this exemplary embodiment, when observed in a plan view from above or below, the mounting base 1 has a shape configured to be similar to the base of an iron.

[0044] In a possible embodiment, the body of the mounting base 1 has a compartment or accommodation space, for example, in a substantially central region, that is, in the region where the second printed circuit board that forms or is part of the electronic circuit 5 is located, and cables, various electronic components, etc. can be accommodated in this compartment or accommodation space.

[0045] As Figure 1 illustrated, the antenna 100 also includes a cover 40 formed of a body having a hollow interior shape, which is, for example, in the shape of a shark fin and made of a plastic material.

[0046] During assembly, the cover 40 is mechanically coupled to the mounting base 1 such that the second printed circuit board that forms or is part of the electronic circuit 5 and the two radiating elements 10 and 20 are accommodated in the cavity of the cover 40.

[0047] Obviously, depending on the application, other components such as gaskets, other signal transmission elements, etc. can be accommodated in the space provided by the cavity of the cover 40; for example, in Figure 1 an additional component 7 configured to receive GPS signals is illustrated.

[0048] The mounting of the mounting base 1 on the roof of a motor vehicle or a suitable mounting surface and the connection of the cover 40 to the same mounting base 1 are carried out in a manner known to or readily available to those skilled in the art, and in any case, it is not relevant to the present invention and is therefore not described in detail herein.

[0049] According to a possible embodiment, the first non-resonant radiation element 10 is configured to receive an analog-type signal and send said analog-type signal to the electronic circuit 5, said analog-type signal being in particular a first signal transmitted in the FM (frequency modulation) band, and the second radiation element 20 is configured to receive a second signal of digital type and send said second signal to the electronic circuit 5, said second signal being in particular a signal transmitted in the DAB band.

[0050] In the illustrated example, the second band, such as the DAB band, is a higher-frequency band with respect to the lower first band, such as the FM band.

[0051] Conveniently, in one possible embodiment, the first non-resonant radiation element 10 is made of a single piece of metallic material, such as tinned steel.

[0052] In particular, the total electrical length of the first non-resonant radiation element 10 is less than the operating wavelength of each band, and in particular the operating wavelength of the band with the higher operating frequency (and thus the shorter wavelength).

[0053] In particular, the total electrical length of the first non-resonant radiation element 10 is equal to or less than 10% of the wavelength at the center of the upper band between the first band and the second band, preferably equal to or less than 5% of said wavelength, more preferably equal to or less than 3% of said wavelength.

[0054] This can contribute to or make the radiation element 10 non-resonant.

[0055] As is known, the electrical length of an element can be defined as its physical length with respect to the operating wavelength.

[0056] If the first non-resonant radiation element 10 is formed by a substantially straight section, the electrical length must be calculated based on the length of said section measured along its center line.

[0057] If the first non-resonant radiation element 10 is formed by two or more sections, the electrical length must be calculated by adding up all the lengths calculated along the center lines of each section.

[0058] For example, in the case of a bent section, once the bent section is considered straightened, the corresponding length can be calculated and added to the other sections.

[0059] In the illustrated exemplary embodiment, the first non-resonant radiation element 10 includes a shaped body configured to fill as much as possible the space dedicated to said shaped body and is accommodated between the cover 40, the printed circuit board forming or included in the electronic circuit 5 and the second radiation element 20.

[0060] According to Figure 1and Figure 2 In a possible embodiment as illustrated in the example of Figure 2 , the shaped body of the first non-resonant radiation element 10 comprises at least a first or lower part 11 having a substantially planar extension, which first or lower part 11 is connected at its first end 12, i.e. at its lower end, to the electronic circuit 5 and rises laterally with respect to the electronic circuit 5, for example along a reference direction or reference axis X, in particular along a direction substantially perpendicular to the second printed circuit board forming or being part of the electronic circuit 5.

[0061] For example, the connection between the first non-resonant radiation element 10 and the electronic circuit 5 is achieved by means of one or more pins, for example by means of two pins 13A and 13B as Figure 1 illustrated, which pins are arranged at the lower end 12 of the first part 11 and are adapted to be inserted into and soldered to corresponding slots arranged on the second circuit board of the electronic circuit 5 at the lower end 12 of the first part 11.

[0062] In a possible embodiment, with reference to the side view, the first non-resonant radiation element 10 is arranged at least such that the substantially planar first part 11 and the second radiation element 20 are substantially aligned in sequence along a direction connecting the front edge 2 and the rear edge 3 of the mounting base 1.

[0063] In a possible embodiment, as Figure 1 and Figure 2 illustrated in the example of Figure 2 , the molded body of the first non-resonant radiation element 10 further comprises a second or upper part 14 configured to implement a capacitive cap.

[0064] The capacitive cap 14 cooperates with the first part 11 having a planar extension and allows optimization of the total emission capacity of the first non-resonant radiation element 10.

[0065] In particular, according to a possible embodiment, with reference to the front view of the antenna 100 (i.e., viewed from the front edge 2 of the mounting base 1), the second part 14 comprises:

[0066] - a first section 15, which first section 15 extends laterally from the second end 16 of the first part 11 opposite the first end 12;

[0067] - a first arm 17, which first arm 17 rises from the first section 15 and is guided away from the mounting base 1;

[0068] - a second section 18, which second section 18 extends laterally from the first arm 17; and

[0069] - The second arm portion 19, which extends from the second section 18 towards the mounting base 1, and the first arm portion 17 and the second arm portion 19 extend from the second section 18 and from opposite sides of the first part 11 so as to diverge with respect to each other.

[0070] Referring to the side view of the antenna 100, the second section 18 travels obliquely downward from the rear edge 3 of the mounting base 1 towards the front edge 2.

[0071] According to this embodiment, the total 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, which is calculated, for example, along the centerline of each section in a plane transverse to the plane in which the electronic circuit 5 is located.

[0072] Such a transverse plane can be, for example, a substantially vertical plane, such as Figure 2 the plane of the page.

[0073] At least one protective element 9 can be arranged around the second part 14 of the first radiating element, which is, for example, a sponge or a piece of self-adhesive foam.

[0074] Such a protective element 9 can also be arranged directly around the first circuit board 22 of the second radiating element 20.

[0075] In a possible embodiment, the electronic circuit 5 includes Figure 3 a first filter stage indicated by reference numeral 50 in Figure 3 a second filter stage indicated by reference numeral 52 in Figure 3 and an active stage indicated by reference numeral 51 disposed between the first filter stage 50 and the second filter stage 52 in

[0076] In particular, according to a possible embodiment, the first filter stage 50 at least includes:

[0077] - A first filter 50A, which is configured to receive the first signal transmitted in the first frequency band and filter the first signal, for example, by eliminating unwanted noise, and to pass the first signal to the active stage 51 and to substantially match the first signal with the input impedance of the active stage 51; and

[0078] - A second filter 50B, which is configured to receive the second signal transmitted in the second frequency band and filter the second signal, for example, by eliminating unwanted noise, and to pass the second signal to the active stage 51 and to substantially match the second signal with the input impedance of the active stage 51.

[0079] In fact, the two filters 50A and 50B are selective filters for a frequency band of interest such as FM or DAB, and are adapted in that the two filters 50A and 50B are configured to compensate for the non-resonant radiating element 10 by making the reactance part of the non-resonant radiating element 10 in the frequency band of interest (FM / DAB) as adapted as possible to the complex conjugate of the input impedance of the active stage 51.

[0080] The complex conjugate is an input impedance value that has a resistance part that is approximately equal to the resistance part of the first non-resonant radiating element 10, and a reactance part that has the same modulus as the reactance part of the first non-resonant radiating element 10 but the opposite sign.

[0081] In addition, these filters can also increase the remaining pure resistance value of the antenna impedance to better match the input value of the active stage 51, and these filters are purely reactive, that is, they do not introduce losses and optimize the performance of each stage from the noise perspective.

[0082] In a possible embodiment, the active stage 51 includes 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.

[0083] In particular, in Figure 3 the illustrated exemplary embodiment, the active stage 51 includes a first active stage 51A and a second active stage 51B operatively associated with the first filter 50A, and a third active stage 51C and a fourth active stage 51D operatively associated with the second filter 50B.

[0084] The first plurality of active stages are configured to have a high input impedance, especially to better match the impedance of the non-resonant radiating element 10.

[0085] In particular, at least the first stage among the first plurality of active stages and the second plurality of active stages is optimized in terms of noise performance, while the subsequent stages among the first plurality of active stages and the second plurality of active stages are configured to optimize at least the dynamic performance in order to achieve an appropriate compromise between the two requirements.

[0086] Obviously, the number of stages of the first plurality of active stages and the second plurality of active stages can be appropriately changed.

[0087] In a possible embodiment, the second filter stage 52 includes at least:

[0088] - A third filter 52A, which is operatively connected to the first active stage 51A and the second active stage 51B, and is configured to allow the first signal to pass through while eliminating noise or unwanted harmonics that may be present in the first signal to be passed through;

[0089] - A fourth filter 52B, operatively connected to the third active stage 51C and the fourth active stage 51D, and configured to allow the second signal to pass while eliminating unwanted noise or harmonics that may be present in the second signal to be allowed to pass.

[0090] In fact, the third filter 52A and the fourth filter 52B are additional selective filters such that only the corresponding signals are allowed to pass in the frequency band of interest (FM / DAB).

[0091] This makes it possible to reduce out-of-band noise and unwanted harmonics such as higher-order harmonics or IM2 second-order intermodulation.

[0092] In a possible embodiment, the electronic circuit 5 further includes a combiner schematically indicated by reference numeral 55 in Figure 3 configured to transmit a first output signal from the third filter 52A and a second output signal from the fourth filter 52B on a common coaxial cable schematically indicated by reference numeral 56 in Figure 3 In this way, the combiner 55 allows the signals (each in its own frequency band) on a single coaxial output cable 56 to be unified, thus optimizing the overall implementation cost.

[0093] Alternatively, in the case of not using the combiner 55, the signals for the first frequency band and the signals for the second frequency band can be routed along two separate cables.

[0094] In fact, it has been made clear that the antenna 100 according to the present invention fully achieves its intended purpose, because compared with known solutions, it has a structure that allows the signals incoming to the two radiating elements 10 and 20 to be more effectively decoupled to optimally utilize the limited space available within the cover 40.

[0095] In addition, the antenna 100 is characterized by the following design: being adapted for use in new motor vehicles and replacing the antennas already installed on in-use motor vehicles.

[0096]

[0097] Of course, without prejudice to the principles of the present invention, the forms of implementation and the details of implementation can vary widely with respect to those described and illustrated by way of non-limiting example only, without thereby departing from the scope of protection of the present invention defined by the appended claims, including any possible combination, even a partial combination, of the above-described embodiments.

[0098] ​For example, the non-resonant radiation element 10 can also receive signals in the AM band. In this case, the AM signal can be processed in parallel with the signals in the other frequency bands by an electronic circuit 50, for example, in the following manner: using low-pass filtering at the input, and then amplifying the AM signal in parallel with the other signals, and then feeding the AM signal into the combiner 55 as well.

Claims

1. An antenna (100) for a motor vehicle, characterized in that, The antenna (100) at least comprises: a mounting base (1) configured to be connected to a mounting surface of the motor vehicle; an electronic circuit (5) adapted to be arranged on the mounting base (1); a first non-resonant radiation element (10) operatively connected to the electronic circuit (5), and the first non-resonant radiation element (10) is configured to receive a first signal transmitted in a first frequency band by one or more devices external to the antenna (100) and send the first signal to the electronic circuit (5); a second radiation element (20) configured to receive a second signal transmitted in a second frequency band different from the first frequency band by one or more devices external to the antenna (100) and send the second signal to the electronic circuit (5), the second radiation element (20) comprises a first printed circuit board (22), the first printed circuit board (22) is arranged on the electronic circuit (5) by means of a first end portion (23) of the first printed circuit board (22) and rises upward from the electronic circuit (5), conductive tracks (24) are arranged along the first printed circuit board (22), the conductive tracks (24) have an end (26) connected to the electronic circuit (5), and the conductive tracks (24) extend along a substantially spiral or serpentine path on the first printed circuit board (22) up to a predetermined height (H); and wherein the electronic circuit (5) is at least configured to process the first signal received from the first non-resonant radiation element (10) and the second signal received from the second radiation element (20) in different ways from each other.

2. The antenna (100) according to claim 1, wherein, The first non-resonant radiation element (10) is made of a single piece of metallic material.

3. The antenna (100) according to claim 1 or 2, wherein, The first non-resonant radiation element (10) comprises a shaped body having at least a first portion (11), the first portion (11) having a substantially planar extension, the first portion (11) being connected to the electronic circuit (5) at a first end (12) of the first portion (11) and rising upward from the electronic circuit (5).

4. The antenna (100) according to claim 3, wherein, Referring to the side view, the mounting base (1) has a front edge (2) and a rear edge (3), and wherein the first non-resonant radiation element (10) is arranged such that the at least one first portion (11) having a substantially planar extension is substantially aligned with the second radiation element (20) along a direction connecting the front edge (2) and the rear edge (3).

5. The antenna (100) according to claim 3 or 4, wherein, The shaped body of the first non-resonant radiation element (10) further includes a second portion (14) which, when viewed from the front, includes: a first portion (15) that extends laterally from a second end (16) of the first portion (11) opposite the first end (12); a first arm portion (17) that rises from the first portion (15) away from the mounting base (1); a second portion (18) that extends laterally from the first arm portion (17); and a second arm portion (19) that extends from the second portion (18) towards the mounting base (1), the first arm portion (17) and the second arm portion (19) extending from the second portion (18) and from opposite sides of the first portion (11) so as to flare relative to each other.

6. The antenna (100) according to one or more of the preceding claims, wherein, The first non-resonant radiation element (10) is configured to receive a first signal transmitted in a frequency modulation band, i.e., an FM band, and send the first signal to the electronic circuit (5), and the second radiation element (20) is configured to receive a second signal transmitted in a digital audio broadcast band, i.e., a DAB band, and send the second signal to the electronic circuit (5).

7. The antenna (100) according to one or more of the preceding claims, wherein, The electronic circuit (5) includes or consists of a printed circuit board disposed on the mounting base (1).

8. The antenna (100) according to one or more of the preceding claims, wherein, The electronic circuit (5) includes a first filter stage (50) and a second filter stage (52), and an active stage (51) disposed between the first filter stage (50) and the second filter stage (52); wherein the first filter stage (50) at least includes: - a first filter (50A) configured to extract the first signal transmitted in the first band and direct the first signal to the active stage (51) and substantially match the first signal to the input impedance of the active stage (51); and - a second filter (50B) configured to extract the second signal transmitted in the second band and direct the second signal to the active stage (51) and substantially match the second signal to the input impedance of the active stage (51); wherein the active stage (51) at least includes a first active stage (51A) and a second active stage (51B) operatively associated with the first filter (50A), and a third active stage (51C) and a fourth active stage (51D) operatively associated with the second filter (50B); and wherein the second filter stage (52) at least includes: - a third filter (52A) operatively connected to the first active stage (51A) and the second active stage (51B) and configured to pass the first signal by eliminating noise or unwanted harmonics potentially present in the first signal to be passed; - A fourth filter (52B) operatively connected to the third active stage (51C) and the fourth active stage (51D) and configured to pass the second signal by eliminating noise or unwanted harmonics potentially present in the second signal to be passed.

9. The antenna (100) according to claim 8, wherein, The electronic circuit (5) further includes a combiner (55) configured to transmit the first signal and the second signal respectively output from the third filter (52A) and the fourth filter (52B) on a common coaxial cable (56).

10. A motor vehicle, characterized in that, The motor vehicle includes at least one antenna (100) according to one or more of the preceding claims.

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