WO2001003235A1

WO2001003235A1 - Multi-purpose antenna for vehicles

Info

Publication number: WO2001003235A1
Application number: PCT/EP2000/006036
Authority: WO
Inventors: Massimo Calearo
Original assignee: Calearo Srl
Priority date: 1999-06-30
Filing date: 2000-06-29
Publication date: 2001-01-11
Also published as: ITVI990138A1; IT1307463B1; AU5979900A; WO2001003235B1; ITVI990138A0

Abstract

The invention realizes a multi-purpose antenna (1) for vehicles comprising: at least one rod (2, 2c) for receiving/transmitting at least one of the AM, FM, GPS and telephone signals, and first electronic means (3, 3a, 3b, 3c) of processing the signals having at least one input port (4, 4c) connected to said at least one rod (2, 2c) and at least two output ports (31, 32, 33, 31a, 32a, 33a, 31b, 32b). The antenna comprises second electronic means (5, 5a, 5b, 5c) of combining said signals, each having at least one input port (51, 52, 53, 51a, 52a, 53a, 51b, 52b) connected to at least one relevant output port (31, 32, 33, 31a, 32a, 33a, 31b, 32b) of said first electronic means (3, 3a, 3b, 3c) and a single output port (6, 6c) for connecting with receiver/transmitter equipment (8) installed on the vehicle.

Description

MULTI-PURPOSE ANTENNA FOR VEHICLES.

The invention concerns a multi-purpose antenna for vehicles that is particularly compact, easy to install and taking up very little space. As is known most vehicles are equipped with multi-purpose antennas that receive AM/FM signals and receive/transmit a telephone signal.

In particular multi-purpose antennas consist of a rod creating the receiver and transmitter monopole aerial, which is connected to a circuit for processing the multiband radiofrequency signal that is received/transmitted, comprising AM, FM and telephone signals. This circuit has the task of supplying the signal to the receiver/transmitter equipment installed on the vehicle connected by two coaxial cables and extract from the multiband signal at least the AM signal and amplify it, inasmuch as this is made necessary by the high level of attenuation that the AM radio signal undergoes when the means of transmission being used is a coaxial cable with typical impedance of 50 Ω or 75 Ω.

In particular this circuit has an input port connected to the antenna's monopole aerial and two output ports, which the circuit provides with the AM and FM radio signals and the telephone signal respectively. After having separated the AM, FM and telephone signals, the circuit gives at least the AM signal, as mentioned earlier, an amplification usually performed by an impedance matching circuit.

The installation requires that the antenna is anchored to the vehicle body and then connected, by a pair of coaxial cables, to the receiver/transmitter equipment installed on the vehicle. One of the main inconveniences of the above system is caused by the need for two coaxial cables to transmit the three AM, FM and radiotelephone signals. In fact this inconvenience, in addition to a more complicated and elaborate installation, also creates an increase in overall costs due to both the cost of each cable and their installation. Another inconvenience is that, for reasons of production tied to the high level of automation reached in the assembly of the actual vehicle, the two connecting cables are in reality made up of a series of jacked cable sections installed on the various assembly parts of the vehicle body, which, when assembling the vehicle, have to be connected together. Another inconvenience tied to the need for jacked cables is their cost combined with the risk of malfunctions, caused by any inadequate connections.

An additional inconvenience in the need for two cables can be seen in the space that these cables occupy inside the vehicle, this space being mainly located at the point where the antenna is anchored to the body, which is extremely restricted.

The scope of this invention is to overcome said inconveniences.

A first particular scope of the invention is to produce a multi-purpose antenna for vehicles that has a single output for the AM, FM and radiotelephone signals connected by a single cable to the vehicle's receiver and transmitter systems.

Another scope of the invention is to produce an antenna that is easy to install even by an unqualified person.

An additional scope of the invention is to produce an antenna having fewer components than similar, known antennas. The aforesaid scopes are achieved by a multi-purpose antenna for vehicles that in accordance with the main claim comprises:

- at least one rod acting as the radiofrequency signal receiver/transmitter monopole aerial comprising AM, FM, GPS and radiotelephone signals;

- first electronic means of processing said radiofrequency signal having at least one input port connected to said at least one rod and at least two output ports each carrying at least one of said radiofrequency signals, and characterised in that it comprises second electronic means of combining said signals, each of which has at least one input port connected to at least one relevant output port of said electronic means of processing said radiofrequency signal and an output port for the processed radiofrequency signal.

An advantage of the antenna under this invention is that it allows to send to the receiver/transmitter unit, the signal received/transmitted along a single connecting cable, maintaining the multiband signal's quality equal to known kinds of antennas, especially for the AM signal.

Another advantage of the antenna invention is that it allows to reduce the space it takes up at the point where it is anchored to the vehicle body and to make assembly as easy as possible, without relinquishing the quality of the signal received/transmitted. Another advantage of the antenna invention is that it allows to reduce the production and installation costs of the actual antenna. Yet another advantage of the antenna invention is that, by reducing the components required in its installation, its weight is reduced by approximately 40%, thereby contributing towards reducing the overall weight of the whole vehicle.

Said scopes and advantages will be better explained during the description of a preferred form of execution of the invention given as a guideline but not a limitation and illustrated in the attached diagrams, where:

- fig. 1 illustrates the multi-purpose antenna invention connected to its relevant receiver/transmitter plant;

- fig. 2 illustrates a block diagram of the circuitry that make up the antenna in fig. 1 ;

- fig. 3 illustrates details of the execution of the block diagram in fig. 2;

- fig. 4 illustrates details of a variant in execution of the block diagram in fig. 2;

- fig.'s 5 and 6 each illustrate details of different variants in execution of the block diagram in fig. 2.

The multi-purpose antenna under this invention, illustrated in fig. 1 where it is generally indicated by 1 , comprises a rod 2, acting as the receiver and transmitter monopole aerial of a multiband radiofrequency signal that comprises AM, FM and telephone signals, and first electronic means 3 of processing this multiband radiofrequency signal, and illustrated in detail in fig. 2. These have an input port 4 electrically wired to the rod 2 and two output ports 31 and 32 each carrying at least one of the AM, FM and telephone signals. The invention prescribes that the antenna 1 comprises second electronic means 5 of combining the signals, each of which has an input port 51 and 52, connected to a respective output port 31 and 32 of the electronic means 3 and a single output port 6 for the processed multiband signal, in order to allow connection by a single cable 7, of the antenna 1 to the receiver/transmitter equipment, generally indicated by 8 installed on the vehicle. It is important to note that both the first electronic means 3 and the second electronic means 5 basically consist of adder elements that define distinct routes for the signals that can be represented by a sequence of filters and impedance matching device. In particular the first electronic means 3 illustrated in detail in fig. 3, comprise, for the AM signal, a low-pass filter 10 and an impedance matching circuit 60, the latter being suited to reducing transmission loss in the AM signal. The FM signal and telephone signal are channelled, by the high-pass filter 20 towards the impedance matching device 61, in this example working either on the FM signal or on the telephone signal to reduce any reflection loss in transmission. The two outputs 31 and 32 therefore have the AM signal and the FM- telephone signal, which become the two input signals for the second electronic means 5 of combining the actual signals. These second electronic means consist of both a low-pass filter 11 suited to preventing the telephone signal, generated by the transmitter unit installed on the vehicle, from interfering with the AM signal and an adder node 50 that combines the AM and FM-telephone signals. The multiband radiofrequency signal that has been processed and then combined in all its AM, FM and telephone components, is thereby supplied to the output port 6 allowing the connection of the antenna to the receiver and transmitter equipment installed on the vehicle by a single coaxial cable 7. It should be noted how each impedance matching device 60 may be made up of passive components or active components, the latter being required in order to amplify the processed signal.

The variant in execution illustrated in detail in fig. 4 differs from the previous in that the three AM, FM and telephone signals are processed separately by an equal number of circuits. In particular the first electronic means 3a of processing the multiband radiofrequency signal illustrated in detail in fig. 4, even separate the FM signal from the telephone signal by a first band-pass filter 12 and a high-pass filter 21.

Even in this case the FM signal is subsequently send to the input of an impedance matching-amplifier device 62 that may consist of active or passive components.

The processed signals are supplied to the three outputs 31a, 32a and 33a respectively, connected to the three input ports 51a, 52a, 53a of the second electronic means 7a of combining the signals generally indicated by 7a. The latter differ from the execution described previously in that they also comprise a band-pass filter 13 for the FM signal, suited to preventing any interference with the telephone signal.

A final variant in execution, illustrated in detail in fig. 5, differs from the others in that the multiband radiofrequency signal is processed so that the AM and FM components are separated from the telephone component. In particular, as can be seen in fig. 5, the first electronic means 3b of processing the multiband signal, comprise, for the AM and FM signals, a first low-pass filter 14 which supplies the input signal to the low-pass filters 15 and high-pass filters 16 that in turn supply the input signal to the impedance matching devices. Finally, the output signal of each impedance matching device is channelled onto an adder node 30 electrically wired to the output 31b.

Output ports 31b and 32b are connected to their relative input ports 51b and 52b of the second electronic means 7b of combining the signals comprising low-pass filter 17. An additional variant in execution, illustrated in detail in fig. 6, differs from the previous executions in that it has a second aerial rod 2c, dedicated, for instance, to receiving a GPS signal, connected to a second input port 4c of the first electronic means 3c. In this case the first electronic means 3c have an additional output 33 for the GPS signal, electrically wired to a third input port 53 of the electronic means 5c of combining the signal, which are all carried by the same output 6c. According to another variant in execution, not illustrated, the antenna invention can have several aerial rods, each dedicated to the radio signal it intends to receive, which, after having been duly processed, is supplied together with the others on the antenna's single output port.

It is important to note that variants in execution may prescribe that both the filters and impedance matching devices are made using active components, therefore suited to giving the signal the necessary amplification to guarantee the desired signal/noise ratio of the signal received/transmitted as required by the whole plant.

However the invention has been described with reference to the figures attached, it may undergo changes in construction, all falling under the claims below and therefore protected by this patent.

Claims

1) Multi-purpose antenna (1) for vehicles comprising:

- at least one rod (2, 2c) acting as the multiband radiofrequency signal receiver/transmitter monopole aerial comprising at least one of the AM, FM, GPS and telephone signals;

- first electronic means (3, 3a, 3b, 3c) of processing said multiband radiofrequency signal having at least one input port (4, 4c) connected to said at least one rod (2, 2c) and at least two output ports (31 , 32, 33, 31a, 32a, 33a, 31b, 32b) each carrying at least one of said signals; characterised in that it comprises second electronic means (5, 5a, 5b, 5c) of combining said signals, each of which has at least one input port (51 , 52, 53, 51a, 52a, 53a, 51b, 52b) connected to at least one relevant output port (31 , 32, 33, 31a, 32a, 33a, 31b, 32b) of said first electronic means (3, 3a, 3b, 3c) of processing said multiband radiofrequency signal and a single output port (6, 6c) for said processed multiband signal, in order to allow connection by a single cable (7), of said output port (6, 6c) with receiver/transmitter equipment (8) installed on the vehicle.

2) Multi-purpose antenna (1) according to claim 1) characterised in that said first electronic means (3, 3a, 3c) of processing the radiofrequency signal comprise for the AM signal, at least one low-pass filter (10) and an impedance matching circuit (60).

3) Multi-purpose antenna (1) according to claim 2) characterised in that said first electronic means (3a, 3c) of processing the radiofrequency signal comprise for the FM signal, at least one band-pass filter (12) and one impedance matching-amplifier circuit (62).

4) Multi-purpose antenna (1) according to claim 2) or 3) characterised in that said impedance matching circuit (60, 62) is an active circuit with amplification greater than one.

5) Multi-purpose antenna (1 ) according to claim 1 ) characterised in that said first electronic means (3b, 3c) of processing the radiofrequency signal comprise for said AM signal at least one first low-pass filter (14) with a second low-pass filter (15) and a first impedance matching circuit and for said FM signal a first low-pass filter (14), a high-pass filter (16) and a second impedance matching circuit. 6) Multi-purpose antenna (1 ) according to claim 5) characterised in that the outputs of each of said impedance matching circuits are connected together on an adder node (30) connected to one of said output ports (31 b).

7) Multi-purpose antenna (1) according to claim 5) or 6) characterised in that at least one of said impedance matching circuit is an active circuit with amplification greater than one.

8) Multi-purpose antenna (1) according to claim 1) characterised in that said second electronic means (5, 5a, 5b, 5c) of combining said signals comprise at least for said AM signal, at least one low-pass filter (11 , 17).

9) Multi-purpose antenna (1) according to claim 1) characterised in that said second electronic means (5a, 5c) of combining said signals comprise for said FM signal at least one band-pass filter (13).

10) Multi-purpose antenna (1) according to claim 2) or 3) or 5) or 8) or 9) characterised in that at least one of said filters (10, 11 , 12, 13, 14, 15, 16, 17, 20, 21) is active.