EP0358529A1 - Antenne zur Befestigung auf einer nichtleitenden Oberfläche, z.B. auf der Scheibe eines Fahrzeuges - Google Patents

Antenne zur Befestigung auf einer nichtleitenden Oberfläche, z.B. auf der Scheibe eines Fahrzeuges Download PDF

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Publication number
EP0358529A1
EP0358529A1 EP89309161A EP89309161A EP0358529A1 EP 0358529 A1 EP0358529 A1 EP 0358529A1 EP 89309161 A EP89309161 A EP 89309161A EP 89309161 A EP89309161 A EP 89309161A EP 0358529 A1 EP0358529 A1 EP 0358529A1
Authority
EP
European Patent Office
Prior art keywords
conductive
antenna according
coupling member
antenna
conductive coupling
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Withdrawn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
EP89309161A
Other languages
English (en)
French (fr)
Inventor
Kevin Davies
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.)
Bantex Ltd
Original Assignee
Bantex Ltd
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 Bantex Ltd filed Critical Bantex Ltd
Publication of EP0358529A1 publication Critical patent/EP0358529A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/1271—Supports; Mounting means for mounting on windscreens
    • H01Q1/1285—Supports; Mounting means for mounting on windscreens with capacitive feeding through the windscreen

Definitions

  • the present invention relates to an antenna and particularly to a communications antenna for mounting on a non-conductive surface such as a window of a vehicle.
  • Communications antennae for vehicles are now well known and various constructions have been proposed.
  • a communications antenna on a window and utilize capacitive coupling of the signal through the glass of the window rather than mount the antenna on a body panel which requires a hole to be drilled through the panel.
  • the dual function of the LC circuit results in a degree of compromise in a practical design with a resulting degradation in performance.
  • the present invention provides a communications antenna for use on a vehicle comprising a tuned circuit arrangement to be interposed between the conductors of a transmission line and a first conductive coupling member arranged to be mounted on one surface of a non-conductive member, on the other surface of which a second conductive coupling member is arranged to be mounted, the tuned circuit comprising an LC circuit arranged to match the impedance of the transmission line, and a further capacitive member for maximising the coupling between the conductive coupling members mounted on the surfaces of the non-conductive member.
  • the further capacitive member is dimensioned to provide a signal at a point adjacent the first coupling member which is in phase with the signal on the first conductive coupling member whereby to reinforce the field in the region of the coupling members.
  • the radiator element is connected to the second coupling member and has a length preferably both physically and electrically 1/4 ⁇ or an odd integer multiple thereof. Such an arrangement can be used at 900 MHz due to the small wavelength at that frequency.
  • a co-axial transmission cable 10 comprises an outer, earthed conductor 11 and an inner signal carrying conductor 12.
  • An impedance matching circuit is connected to the transmission cable 10 and comprises an inductance L1 one end 14 of which is earthed and the other end 15 of which is connected to one plate 16 of a coupling capacitance C3.
  • a capacitance C1 is connected in parallel with the inductance L1.
  • a further capacitance C2 is provided between the plate 16 of the coupling capacitance C3 and earth in order to optimize the value of the coupling capacitance C3 to provide in phase signals for maximising signal transfer through the coupling capacitance C3.
  • the need to optimise the coupling capacitance comes about due to the fact that the area of the plate 16 is determined by the capacitance required to provide the correct matching impedance for connection to the transmission line. Further, the thickness of the glass, i.e. the separation of the plates constituting the coupling capacitance C3 is predetermined. Unfortunately, if one were to simply attach an outer coupling member of the same or larger area than the area of the inner coupling member, the capacitance would not be correct for efficient signal coupling.
  • the inner conductor 12 is connected to the inductance L1 at a position intermediate the ends of the inductance L1 so as to match the impedance at the base of a radiator 21 to the impedance of the transmission cable 10 at the desired resonant frequency of the antenna.
  • FIG 2 shows diagrammatically how to implement the circuit diagram shown in Figure 1.
  • the same reference numerals have been used to represent the same parts.
  • Reference numeral 20 indicates the glass on one surface 18 of which is attached a planar member. At least the surface of the member adjacent the glass 20 is conductive and forms the plate 16 of the capitance C3 whose other plate 17 is affixed to the external surface 19 of the glass 20.
  • the radiator 21 is attached to the plate 17.
  • the capacitance C1 is formed by the conductive member constitutes the p late 16 and by a further planar member 22 at least one surface of which is conductive.
  • the inductance L1 is formed by a wire extending between the plate 16 and member 22.
  • the capitance C2 is formed by the conductive surface of the planar member forming the plate 16 and by a conductive foil 24 extending from one edge of the member 22 towards the edge of the plate 16 but separated therefrom by a distance suitable to establish the correct value for the capitance C2.
  • the foil 24 has a portion 25 which extends in the plane 16.
  • the length, breadth and thickness of the foil 24 are chosen to provide not only the correct value for the capitance C2 but also the correct electrical length of the path from the connection point 26 between the carrier conductor 12 and the inductor L1 along the member 22 and through the foil 24.
  • the extent of the portion 25 is not critical for co-phasing signals at the edges of the plate 16 and foil 24 but is designed to ensure that the tuned circuit exhibits the required high impedance to signals attempting to flow back to the outer conductor 11 of the transmission line.
  • This arrangement of tuned circuit will support a radiator 21 which is both physically and electrically 1/4 ⁇ in length or the usual radiator combinations which are an odd integer multiple thereof in order to achieve the desired gain. Because the radiator 21 is 1/4 ⁇ the bottom of the radiator is current fed and is at a low impedance, typically less than 50 ⁇ .
  • the wire forming the inductor L1 may be a 6mm length of 18 SWG tinned copper wire
  • the plate 16 and member 22 may be single sided printed circuit boards of size 35 x 20 mm and the end portion 25 of the foil 24 may extend from the edge of the plate 16 by a distance of 10 mm.
  • Figure 3 shows a housing 29 for the circuit and comprises a surface 30 having a first opening 31 for the plate 16 and a further opening 32 for the portion 25 of the foil 24.
  • the two openings are separated by a wall which stabilizes the cap between the edge of the plate 16 and the foil 24.
  • the surface 30 is provided with an adhesive layer and is attached to the inner surface of a window of a vehicle.
  • the above arrangement thus has the advantage that the antenna is matched to the transmission line and the transmission of the signal through the glass is maximised. Further, because it is not a ground plane type antenna the amount of restriction to rear view or distraction to the driver is reduced to a minimum.
  • Ground plane antenna either have short stubs which are unsightly and restrict vision or else ground mats in the forms of adhesive strips of foil stuck to the glass which not only restrict vision but also render the antenna difficult to install.

Landscapes

  • Details Of Aerials (AREA)
EP89309161A 1988-09-09 1989-09-08 Antenne zur Befestigung auf einer nichtleitenden Oberfläche, z.B. auf der Scheibe eines Fahrzeuges Withdrawn EP0358529A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888821171A GB8821171D0 (en) 1988-09-09 1988-09-09 Antenna
GB8821171 1988-09-09

Publications (1)

Publication Number Publication Date
EP0358529A1 true EP0358529A1 (de) 1990-03-14

Family

ID=10643317

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89309161A Withdrawn EP0358529A1 (de) 1988-09-09 1989-09-08 Antenne zur Befestigung auf einer nichtleitenden Oberfläche, z.B. auf der Scheibe eines Fahrzeuges

Country Status (4)

Country Link
EP (1) EP0358529A1 (de)
AU (1) AU4205389A (de)
GB (1) GB8821171D0 (de)
WO (1) WO1990003048A1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0542473A1 (de) * 1991-11-05 1993-05-19 Nippon Sheet Glass Co., Ltd. Scheibenantennenvorrichtung
US5307076A (en) * 1991-11-05 1994-04-26 Nippon Sheet Glass Co., Ltd. Window glass antenna device
EP0642189A1 (de) * 1993-09-02 1995-03-08 SAT (Société Anonyme de Télécommunications),Société Anonyme Antenne für tragbares Funkgerät
FR2898715A1 (fr) * 2006-03-17 2007-09-21 Valeo Securite Habitacle Sas Procede et dispositif permettant d'acheminer un signal electromagnetique entre un organe situe dans un environnement exterieur et une unite de traitement situee a l'interieur d'un espace confine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4089817A (en) * 1976-10-12 1978-05-16 Stephen A. Denmar Antenna system
EP0137391A1 (de) * 1983-09-23 1985-04-17 Allen Telecom Group, Inc. Antenne für den mobilen Telefonverkehr
US4825217A (en) * 1987-10-19 1989-04-25 Tae Lim Electronics Co., Ltd. Car phone antenna assembly

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4089817A (en) * 1976-10-12 1978-05-16 Stephen A. Denmar Antenna system
EP0137391A1 (de) * 1983-09-23 1985-04-17 Allen Telecom Group, Inc. Antenne für den mobilen Telefonverkehr
US4825217A (en) * 1987-10-19 1989-04-25 Tae Lim Electronics Co., Ltd. Car phone antenna assembly

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TELECOMMUNICATIONS & RADIO ENGINEERING, vol. 40/41, no. 10, October 1986, pages 144-146, Scripta Technica, Inc., Silver Spring, Maryland, US; G.G. CHAVKA et al.: "Synthesis of multiband matching networks" *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0542473A1 (de) * 1991-11-05 1993-05-19 Nippon Sheet Glass Co., Ltd. Scheibenantennenvorrichtung
US5307076A (en) * 1991-11-05 1994-04-26 Nippon Sheet Glass Co., Ltd. Window glass antenna device
EP0642189A1 (de) * 1993-09-02 1995-03-08 SAT (Société Anonyme de Télécommunications),Société Anonyme Antenne für tragbares Funkgerät
FR2709604A1 (fr) * 1993-09-02 1995-03-10 Sat Antenne pour appareil radio portatif.
FR2898715A1 (fr) * 2006-03-17 2007-09-21 Valeo Securite Habitacle Sas Procede et dispositif permettant d'acheminer un signal electromagnetique entre un organe situe dans un environnement exterieur et une unite de traitement situee a l'interieur d'un espace confine

Also Published As

Publication number Publication date
GB8821171D0 (en) 1988-10-12
AU4205389A (en) 1990-04-02
WO1990003048A1 (en) 1990-03-22

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