EP1329986A1 - Antenne compacte pour vehicule - Google Patents

Antenne compacte pour vehicule Download PDF

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Publication number
EP1329986A1
EP1329986A1 EP02001222A EP02001222A EP1329986A1 EP 1329986 A1 EP1329986 A1 EP 1329986A1 EP 02001222 A EP02001222 A EP 02001222A EP 02001222 A EP02001222 A EP 02001222A EP 1329986 A1 EP1329986 A1 EP 1329986A1
Authority
EP
European Patent Office
Prior art keywords
antenna according
vehicle antenna
mhz
antenna
shaped element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02001222A
Other languages
German (de)
English (en)
Inventor
Roberto Ronzani
Federico Iacovella
Alberto Dalle Rive
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Calearo Antenne SpA
Original Assignee
Calearo Srl
Calearo Antenne SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Calearo Srl, Calearo Antenne SpA filed Critical Calearo Srl
Priority to EP02001222A priority Critical patent/EP1329986A1/fr
Publication of EP1329986A1 publication Critical patent/EP1329986A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
    • H01Q9/32—Vertical arrangement of element
    • H01Q9/36—Vertical arrangement of element with top loading
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/27—Adaptation for use in or on movable bodies
    • H01Q1/32—Adaptation for use in or on road or rail vehicles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/362—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith for broadside radiating helical antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/342—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
    • H01Q5/357—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point

Definitions

  • the present invention relates to a compact antenna for vehicles such as motor cars, lorries or the like, in particular for the use of transceiver equipment.
  • the antennae used in the sector of vehicles for road travel are generally composed of a fixed part and a movable part which forms the rod of the antenna.
  • the fixed part is mounted projecting on the vehicle bodywork at a maximum height which is normally subject to restrictions defined in compliance with precise safety regulations for vehicles.
  • these regulations may impose tighter restrictions for antennae designed for passive operation than for antennae associated with active components.
  • a passive antenna i.e. an antenna without a transistor or amplification components
  • the correct transmission of the signal may require the insertion of a match circuit consisting, for example, of a substantially loss-free LC circuit.
  • the transmission of telephone signals may be performed by means of transceiver equipment able to communicate in one or more frequency bands.
  • transceiver equipment able to communicate in one or more frequency bands.
  • cellular phones able to operate at the frequencies of 900 MHz or 1800 MHz or selectively at both the abovementioned frequencies are known. These frequencies correspond, for resonance at ⁇ /4, to antennae with a length of about 8 and 4 cm, respectively.
  • Rodless antennae which, for reasons of constructional simplicity and low production costs, do not envisage the use of active components for signal amplification must necessarily operate by means of resonance for optimisation of transmission. This means that the form, and in particular the height, of these antennae are greatly dependent upon the restrictions imposed by the wavelengths of the transmission frequencies.
  • antennae have been made, for example with a reduced height, obtained by means of conductor elements which are helically wound in the manner of springs, but nevertheless have a resonance behaviour which is same as corresponding conductor elements with heights of ⁇ /4, 5/8 ⁇ and 1/2 ⁇ .
  • antennae obtained by means of thin metallised filaments formed on large printed-circuit areas also able to transmit by means of the principle of resonance, but with a reduced height, have also been developed.
  • the small thickness of the conductor element limits in practice the band widening effect due to the area described by the spirals (which allows better reception in a wider frequency range).
  • the filaments formed in printed circuits although achieving resonance with low heights, result in an undesirable limitation of the passband due to the limited thickness of the filaments and the limited volumetric space present between the said filaments. This fact therefore offsets the positive effect of widening of the resonance range due to the form of the spirals designed on the printed circuit.
  • a further drawback which has not yet been entirely solved consists in the difficulty of providing an antenna which allows optimum operation both at the frequency of 900 MHz and at the frequency of 1800 MHz and which at the same time has a reduced height.
  • the essential object of the present invention is therefore that of eliminating the drawbacks of the art as described above, by providing a compact antenna for vehicles which projects from the vehicle over a limited height and allows at the same time resonance operation for the transmission of telephone signals in all the frequency bands used by transceiver equipment.
  • Another object of the present invention is in particular that of providing an antenna, in particular devoid of active components, which allows the transmission of telephone signals both in the frequency band of 900 MHz and in the frequency band of 1800 MHz.
  • Another object of the present invention is that of providing an antenna which has extremely low production costs and a low loss factor.
  • a further object of the present invention is that of providing an antenna which is constructionally simple and operationally entirely reliable.
  • 1 denotes in its entirety the compact antenna for vehicles according to the present invention.
  • the antenna 1 is devoid of a removable rod and is composed, as illustrated in Figs. 1-5, exclusively of a fixed part mounted projecting on the bodywork of the vehicle.
  • the abovementioned antenna 1 is advantageously used to allow operation of transceiver equipment such as, for example, cellular phones operating in various frequency bands.
  • said antenna does not require the use of active components such as signal amplifiers or modulators and allows resonance to be achieved as well as transmission with passbands which are sufficiently wide despite having extremely small dimensions.
  • the antenna 1 is intended to operate both in a frequency band of 900 MHz and in a frequency band of 1800 MHz, i.e. in both the bands commonly used in mobile phones.
  • the antenna in question may be used for operation in a single frequency band or in several frequency bands also different from those mentioned above, since, by means of simple correction of the dimensions of the antenna components, it is possible to achieve resonance at different frequencies while using the same inventive idea.
  • the antenna 1 comprises a resonant element 2 composed of a shaped element 3 made of metallic material and connected in a circuit arrangement to the transceiver equipment 4 (such as, in particular, a mobile phone) and a metallic conductor 5 which is helically wound and connected at the bottom electrically to the shaped element 3.
  • the transceiver equipment 4 such as, in particular, a mobile phone
  • a metallic conductor 5 which is helically wound and connected at the bottom electrically to the shaped element 3.
  • the shaped element 3 consists of a metallised portion with an elongated shape formed on a support for electronic circuits traditionally realised as a printed circuit.
  • the shaped metallic element 3 may also assume other constructional forms different from that mentioned above, such as, for example, the form of a tube or a metal plate, without thereby departing from the scope of protection of the present invention.
  • the shaped metallic element 3 will be provided with a cross-section, with respect to its main extension, having a perimetral contour with a substantially large extension compared to the area of the said cross-section.
  • the height required for resonance may be reduced, in particular for the low-frequency band at 900 MHz, while on the other hand the width of the passband during transmission of the signals is not adversely affected.
  • transceiver equipment 4 consisting of cellular phones operating in the bands of 900 MHz and 1800 MHz
  • the resonance element 2 it is possible, firstly, to obtain resonance at 900 MHz with a real height H of the resonant element 2 less than that envisaged for ⁇ /4 and, secondly, to ensure in all cases optimum transmission of the signals also in the higher band of 1800 MHz.
  • the antenna 1 owing to the configuration of the resonant element 2 divided into two differently shaped parts, it is possible to achieve resonance at 900 MHz with a height less than that envisaged for operation at ⁇ /4.
  • the antenna 1 according to the present invention if the spring conductor 5 is regarded as a single block, at the same time also achieves resonance transmission for the band of 1800 MHz.
  • the total height H obtained by the sum of the height H' of the shaped element 3 and the height H" of the spring conductor 5 corresponds therefore to the length of ⁇ /4 for operation at 1800 MHz, i.e. to about 4 cm.
  • the width of the spirals 5' of the spring allows the passband to be widened at 900 MHz, with the advantages of improved signal transmission and a reduction in reflection losses.
  • the metallic conductor 5 is wound helically around an upper non-metallised portion 7 of the printed circuit 6, made of a dielectric material able to ensure a charging effect, while ensuring in all cases a low signal transmission loss factor.
  • the abovementioned upper portion 7 may also perform the function of a mechanical support for the helically wound conductor 5.
  • the machines used in traditional spring-manufacturing plants are able to form a metal wire into a spring with spirals of the desired shape in a sufficiently precise manner and with sufficiently small tolerances (for example less than one tenth of a mm).
  • the same machinery designed for production of the springs ensure a similar precision in cutting of the free end 15 only if the latter is envisaged as projecting from the spirals of the conductor 5 in a displaced position, able to allow easy cutting thereof from the remainder of the conductor using a special tool.
  • the free end 15 must extend preferably in the horizontal direction rather than in the vertical direction.
  • the antenna part represented by the helically wound conductor 5 may be produced by means of an industrial process which, while being entirely automatic and therefore ultimately relatively inexpensive, at the same time is sufficiently precise to ensure the tolerances necessary for optimum electrical operation.
  • a match circuit 8 may be advantageously used, said circuit being composed, for example, of two inductances 9 arranged in series and connected, on the one hand, to the antenna cable 10 and, on the other hand, to the base 11 of the shaped element 3 and separated by a capacitance 12 connected to earth (see Fig. 6).
  • the match circuit is preferably provided in a second printed circuit 13 which is substantially horizontal and into which additional elements 14 of the active or passive type for other intended functions of the antenna 1, such as for example satellite navigation by means of a GPS system, may be introduced.
  • the compact antenna 1 described hitherto from a mainly structural point of view allows the operation, in particular without the use of active components, also for the low frequency bands available today on the market (and in particular for the 900 MHz band), by means of a particular form of the resonant element 2 which retains an extremely small height.
  • the same antenna 1 is designed to be used advantageously in association with the cellular phones which are available today on the market and which use two different transmission bands (900 MHz and 1800 MHz).
  • the antenna in question offers the advantage, in the examples of embodiment illustrated above, of having an extremely compact form, a low production cost and optimum performance characteristics both at the low frequencies (900 MHz) and at the high frequencies (1800 MHz) in particular without the use of active components.
  • the antenna in question is advantageously designed for resonance operation in the bands of 900 MHz and 1800 MHz used by mobile phones commercially available nowadays, without the need for introducing active circuit components.
  • the height H of the resonant element 2 is of substantial importance for determining the operation of the antenna 1 in the higher band, while its form is decisive for operation of the antenna 1 in the lower band.
  • the invention thus conceived therefore achieves the predefined objects.
EP02001222A 2002-01-17 2002-01-17 Antenne compacte pour vehicule Withdrawn EP1329986A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP02001222A EP1329986A1 (fr) 2002-01-17 2002-01-17 Antenne compacte pour vehicule

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP02001222A EP1329986A1 (fr) 2002-01-17 2002-01-17 Antenne compacte pour vehicule

Publications (1)

Publication Number Publication Date
EP1329986A1 true EP1329986A1 (fr) 2003-07-23

Family

ID=8185286

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02001222A Withdrawn EP1329986A1 (fr) 2002-01-17 2002-01-17 Antenne compacte pour vehicule

Country Status (1)

Country Link
EP (1) EP1329986A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4656483A (en) * 1983-09-28 1987-04-07 Avions Marcel Dassault-Breguet Aviation Switchable antenna for the VHF and UHF frequency bands
EP0896384A2 (fr) * 1997-08-07 1999-02-10 Tokin Corporation Antenne multibande utilisable dans un dispositif de radiocommunication mobile
WO2001018903A2 (fr) * 1999-09-08 2001-03-15 Siemens Aktiengesellschaft Antenne radio mobile a unite fonctionnelle integree
US6271804B1 (en) * 1997-01-28 2001-08-07 Yokowo Co., Ltd. Antenna for mounting on vehicle, antenna element and manufacturing method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4656483A (en) * 1983-09-28 1987-04-07 Avions Marcel Dassault-Breguet Aviation Switchable antenna for the VHF and UHF frequency bands
US6271804B1 (en) * 1997-01-28 2001-08-07 Yokowo Co., Ltd. Antenna for mounting on vehicle, antenna element and manufacturing method thereof
EP0896384A2 (fr) * 1997-08-07 1999-02-10 Tokin Corporation Antenne multibande utilisable dans un dispositif de radiocommunication mobile
WO2001018903A2 (fr) * 1999-09-08 2001-03-15 Siemens Aktiengesellschaft Antenne radio mobile a unite fonctionnelle integree

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