EP1793449A1

EP1793449A1 - Vehicular multiband antenna for mobile telephony

Info

Publication number: EP1793449A1
Application number: EP06123830A
Authority: EP
Inventors: Enrico Toniolo
Original assignee: Calearo Antenne SpA
Current assignee: Calearo Antenne SpA
Priority date: 2005-11-11
Filing date: 2006-11-10
Publication date: 2007-06-06
Also published as: ITVI20050300A1

Abstract

Vehicular multiband antenna (1) for mobile telephony, comprising: a dielectric support (2); a first transceiver unit (3) comprising a first electrically conductive laminar element (5) operatively connected to a transceiver line for signals and applied to a surface (7) of the dielectric support (2); a second transceiver unit (4) comprising a second electrically conductive laminar element (6) operatively connected to the transceiver line for signals and applied to the surface (7) of the dielectric support (2). The vehicular multiband antenna (1) comprises a third electrically conductive laminar element (8) that develops substantially parallel to the first laminar element (5), applied to the surface (7) of the dielectric support (2) and provided with one earthing point (10).

Description

The invention concerns a vehicular multiband antenna particularly suited to be used for transmitting and receiving radio-frequency signals for mobile telephony.
It is known that mobile telephones transmit and receive radio-frequency signals on dedicated frequency bands that are different from one another depending on the mobile telephony standards.
Usually a frequency band centered on a lower frequency (around 900MHz) and one or more frequency bands centered on higher frequencies (around 2GHz) are used.
It is also known that telephone companies worldwide often use, for mobile telephony, different transmitting and receiving standards with corresponding bands that, though having overlapping points, differ from one another.
The vehicular antennas belonging to the known art are all distinguished by the fact that they are compatible with one or more transmitting and receiving standards, but not with all the existing standards.
The obvious drawback originating from the above lies in that a motor vehicle designed for transmitting and receiving mobile telephony radio-frequency signals must be customised with different types of antennas depending on its target market.
A further inconvenience is constituted by the fact that in order to be compatible with all the existing mobile telephony services worldwide a motor vehicle must be equipped with a bulky and cumbersome system of antennas.
The aim of the present invention is to overcome all the drawbacks described.
In particular, a first aim of the invention is to carry out a vehicular multiband antenna that is capable of correctly receiving radio-frequency signals in the frequency bands used by all mobile telephony standards.
A further aim of the invention is to carry out a vehicular multiband antenna whose dimensions can be compared with or are smaller than those of the antennas belonging to the known art and suited to receive only the radio-frequency signals of some transmitting and receiving standards for mobile telephony.
The above mentioned aims have been achieved through the implementation of a vehicular multiband antenna for mobile telephony, comprising:

a dielectric support;
at least a first transceiver unit comprising a first electrically conductive laminar element operatively connected to a transceiver line for signals and applied to a surface of said dielectric support;
at least a second transceiver unit comprising a second electrically conductive laminar element operatively connected to said transceiver line for signals and applied to said surface of said dielectric support;

According to the invention, each one of the first, second and third laminar elements has a surface delimited by a perimeter consisting of an irregular line and at least one enlarged area.
Furthermore, the vehicular multiband antenna that is the subject of the invention comprises a plurality of electrically conductive shaped areas that are independent of one another and arranged on the second surface of the dielectric support.
To advantage, the arrangement of the vehicular multiband antenna on a single dielectric support allows a particularly compact vehicular multiband antenna for mobile telephony to be obtained.
Still to advantage, the presence of the third electrically conductive laminar element with one earthing point makes it possible to carry out, with the first laminar element beside which the third laminar element develops, a sort of double-wire structure that is well suited to the impedance adaptation described below.
Still to advantage, also the plurality of electrically conductive shaped areas arranged on the second surface of the dielectric support facilitate the impedance adaptation mentioned above.
The aforesaid objects and advantages, and others that will be described below, will be highlighted in greater detail in the description of a preferred embodiment of the invention, provided here as a nonrestrictive example, with reference to the attached drawings, wherein:

Figure 1 is an exploded axonometric view of the vehicular multiband antenna carried out according to the invention;
Figures from 2 to 5 show axonometric views of some details of the vehicular multiband antenna carried out according to the invention.

The vehicular multiband antenna for mobile telephony that is the subject of the invention is represented in Figure 1, where it is indicated as a whole by 1 and where it is possible to see that it comprises a single dielectric support 2 on which there are a first transceiver unit 3 and a second transceiver unit 4.
Said embodiment is described only as an example and does not represent a limitation for other embodiments in which the transceiver units are present in a number different from two.
The transceiver unit 3 comprises a first electrically conductive laminar element 5 operatively connected to a transceiver line for signals and applied to a surface 7 of the dielectric support 2, while the second transceiver unit 4 comprises a second laminar element 6, which is also electrically conductive, operatively connected to the transceiver line for signals and applied to the same surface 7 of the dielectric support 2.
According to the invention, the vehicular multiband antenna 1 comprises a third electrically conductive laminar element 8 applied to the first surface 7 of the dielectric support 2 and provided with one earthing point 10.
The third laminar element 8 develops substantially parallel to the first laminar element 5, thus creating a structure similar to a double-wire line.
The first, the second and the third laminar element 5, 6 and 8, as shown in Figures 2, 3 and 4, each have the surface 12, 13 and 14 delimited by a perimeter 12a, 13a and 14a constituted by an irregular line that, according to the preferred embodiment of the invention described herein, is a broken line.
According to other embodiments of the invention not illustrated and described herein, the irregular line is a mixed line.
As regards the first laminar element 5, it comprises a section 15 that is substantially filiform with an enlarged terminal area 16 having a recess 17 facing the second laminar element 6.
According to the preferred embodiment of the invention described herein, said recess 17 defines an obtuse angle α.
It should be noted that said embodiment, though being the preferred embodiment of the invention, is described only as an example and does not represent a limitation for further embodiments where the angle α is not obtuse.
As regards the second laminar element 6, it comprises a lateral projecting area 18 facing the filiform section 15 of the first laminar element 5, and a terminal projecting area 19 facing the recess 17 of the terminal area 16 of the first laminar element 5.
As regards the third laminar element 8, it comprises a substantially filiform section 20 and an enlarged terminal area 21.
It should be noted that the enlargement of some parts of the laminar elements 5, 6 and 8 makes it possible to enlarge the frequency bands in which the corresponding transceiver units 3 and 4 are capable of transmitting and receiving, thus allowing the vehicular multiband antenna 1 that is the subject of the invention to be compatible with all the transmitting and receiving standards of mobile telephony at the same time.
Furthermore, the shape of the laminar elements 5, 6 and 8, generating the irregular line that delimits their perimeters 12a, 13a, 14a, makes it possible to modify the electromagnetic interactions between the laminar elements 5, 6 and 8 to carry out an impedance adaptation process.
It is known, in fact, the typical impedance for transmitting and receiving radio-frequency signals for mobile telephony is 50 Ohm, while air impedance is almost 370 Ohm, so that in order to obtain the best transmitting and receiving results an adaptation between the two impedance values is necessary.
It is also known that such impedance adaptation can be easily obtained on double-wire lines like the one substantially produced by the coupling between the first and the third laminar element.
In this regard, as can be observed in Figure 1, the third laminar element 8 is spaced from the first laminar element 5 by a section 22 having irregular thickness, in which the portion 22a that separates the third laminar element 8 from the enlarged terminal area 16 of the first laminar element 5 is substantially L-shaped and is thinner than the remaining portion 22b of said section 22 having irregular thickness.
It should once again be noted that said embodiment, though being the preferred embodiment of the invention, is described only as an example and does not represent a limitation for further embodiments where the portion 22a is not L-shaped.
It should also be noted that the shape of the third laminar element 8, as well as the section with irregular thickness 22 that separates it from the first laminar element 5, advantageously facilitate the desired impedance adaptation.
It should also be noted that the third laminar element 8 interacts with the second laminar element 6 in order to achieve for it, too, the necessary impedance adaptation.
The vehicular multiband antenna 1 that is the subject of the invention also comprises a plurality of shaped areas 25, represented in Figure 5, electrically conductive and independent of one another, arranged on the surface 26 of the dielectric support 2 opposite the surface 7 on which the laminar elements 5, 6 and 8 are positioned, in order to obtain a plurality of capacitive couplings with the laminar elements 5, 6 and 8.
Also said shaped areas 25, therefore, advantageously facilitate the desired impedance adaptation mentioned above.
Finally, it is important to point out that, as shown in Figure 1, the first laminar element 5 is longer than the second laminar element 6, so that it is possible to transmit and receive radio-frequency signals on different bands.
Furthermore, preferably, but not necessarily, the third laminar element 8 defines a concave area 11 to which the first and the second laminar elements 5 and 6 are applied.
For the reasons explained above, the vehicular multiband antenna for mobile telephony that is the subject of the invention achieves all the set aims.
In particular, it achieves the aim to carry out a vehicular multiband antenna that is capable of correctly receiving radio-frequency signals in all the frequency bands used by the different mobile telephony standards.
The invention also achieves the aim to carry out a vehicular multiband antenna to transmit and receive radio-frequency signals for all the mobile telephony standards that has the same overall dimensions as the known antennas and suited to transmit and receive signals for some standards only.
Upon implementation, further construction variants of the vehicular multiband antenna may be carried out.
These changes, although not represented in the drawings and not described herein, must all be considered protected by the present patent, provided that they fall within the scope of the following claims.
Where the technical characteristics illustrated in the claims are followed by reference numbers, these are provided for the sole purpose of facilitating the reader and said reference numbers shall consequently have no restrictive effect on the coverage of each element identified as an example.

Claims

Vehicular multiband antenna (1) for mobile telephony, comprising:
- a dielectric support (2);

- at least a first transceiver unit (3) comprising a first electrically conductive laminar element (5) operatively connected to a transceiver line for signals and applied to a surface (7) of said dielectric support (2);

- at least a second transceiver unit (4) comprising a second electrically conductive laminar element (6) operatively connected to said transceiver line for signals and applied to said surface (7) of said dielectric support (2),
characterized in that it comprises at least one third electrically conductive laminar element (8) that develops substantially parallel to said first laminar element (5), applied to said surface (7) of said dielectric support (2) and provided with at least one earthing point (10).
Vehicular multiband antenna (1) according to claim 1),
characterized in that said first (5) and third (8) laminar elements create an open double-wire line.
Vehicular multiband antenna (1) according to claim 1),
characterized in that each of said first (5), second (6) and third (8) laminar elements has the surface (12, 13, 14) delimited by a perimeter (12a, 13a, 14a) constituted by an irregular line.
Vehicular multiband antenna according to claim 3), characterized in that said irregular line is a mixed line.
Vehicular multiband antenna (1) according to claim 3),
characterized in that said irregular line is a broken line.
Vehicular multiband antenna (1) according to claim 1),
characterized in that said first laminar element (5) comprises a substantially filiform section (15) with an enlarged terminal area (16) having a recess (17) facing said second laminar element.
Vehicular multiband antenna (1) according to claim 1),
characterized in that said recess (17) defines an obtuse angle (α).
Vehicular multiband antenna (1) according to claim 6),
characterized in that said second laminar element (6) comprises at least one lateral projecting area (18) facing said filiform section (15) of said first laminar element (5), and at least one terminal projecting area (19) facing said recess (17) of said terminal area (16) of said first laminar element (5).
Vehicular multiband antenna (1) according to claim 6),
characterized in that said third laminar element (8) comprises a substantially filiform section (20) with an enlarged terminal area (21), said third laminar element (8) being spaced from said first laminar element (5) by a section (22) with irregular thickness.
Vehicular multiband antenna (1) according to claim 6),
characterized in that said section with irregular thickness (22) has a portion (22a), substantially L-shaped and thinner than the remaining portion (22b) of said section with irregular thickness (22), that separates said third laminar element (8) from said enlarged area (16) of said first laminar element (5).
Vehicular multiband antenna (1) according to claim 1),
characterized in that said third laminar element (8) defines a concave area (11) containing said first (5) and second (6) laminar elements.
Vehicular multiband antenna (1) according to claim 1),
characterized in that said first laminar element (5) is included between said third laminar element (8) and said second laminar element (6).
Vehicular multiband antenna (1) according to claim 1),
characterized in that it comprises a plurality of shaped areas (25), electrically conductive and independent of one another, arranged on the surface (26) of said dielectric support (2) opposite the surface (7) to which said laminar elements (5, 6, 8) are applied, said shaped areas (25) being suited to carry out capacitive couplings with said laminar elements (5, 6, 8).
Vehicular multiband antenna (1) according to claim 1),
characterized in that said first laminar element (5) is longer than said second laminar element (6).
Vehicular multiband antenna (1) according to claim 1),
characterized in that said laminar elements (5, 6, 8) are metallic surfaces silk-screen printed on said dielectric support (2).