WO1996002075A1 - Systeme combine d'antenne de telephone cellulaire am/fm - Google Patents

Systeme combine d'antenne de telephone cellulaire am/fm Download PDF

Info

Publication number
WO1996002075A1
WO1996002075A1 PCT/US1995/008528 US9508528W WO9602075A1 WO 1996002075 A1 WO1996002075 A1 WO 1996002075A1 US 9508528 W US9508528 W US 9508528W WO 9602075 A1 WO9602075 A1 WO 9602075A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
antenna rod
coaxial
frequency range
rod
Prior art date
Application number
PCT/US1995/008528
Other languages
English (en)
Inventor
Glen J. Seward
Robert M. Lynas
Paul E. Miller
Robert B. Ennenga
Original Assignee
R.A. Miller Industries, Inc.
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 R.A. Miller Industries, Inc. filed Critical R.A. Miller Industries, Inc.
Publication of WO1996002075A1 publication Critical patent/WO1996002075A1/fr

Links

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
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • 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
    • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
    • H01Q5/321—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors within a radiating element or between connected radiating elements
    • 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
    • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
    • H01Q5/48—Combinations of two or more dipole type antennas

Definitions

  • This invention relates to motor vehicle antennae and more particularly to a multiband AM/FM/cellular telephone antenna system suitable for use on automotive vehicles. Description of the Related Art
  • the cellular telephone system typically requires a separate antenna.
  • the cellular antenna may be factory-installed original equipment or subsequently installed after-market equipment.
  • Earlier cellular telephones required substantial amount of electrical equipment stored in the trunk of the car and wiring was required from the front of the passenger compartment to the rear of the car and to the antenna.
  • the antenna is typically a rear window mounted antenna or a trunk lid antenna.
  • the wiring is a time-consuming job which adds substantially to the cost of installation of the cellular telephone in the vehicle.
  • More modern cellular telephone systems use more compact circuitry which is often installed underneath the front seat. Thus, much of the wiring between the passenger compartment and the trunk is avoided.
  • the wiring between the cellular telephone, typically mounted near the driver, and the antenna, typically mounted near the rear window still requires a substantial amount of wiring.
  • the wiring is preferably hidden from view behind the roof headliner, or the like, which adds substantially to the cost of installation, particularly for after-market installation.
  • the AM/FM antenna is almost always a rod antenna.
  • the cellular telephone antenna typically includes a helically wound coil near the middle of the antenna. The coil improves the effectiveness of the antenna by impeding phase reversal, but detracts from the overall appearance. Furthermore, a well-known problem with the cellular telephone antenna of that type is the wind noise or whistle caused by the coil when the vehicle travels at highway speeds.
  • Portable vehicular cellular telephones offer flexibility in that they may be taken from vehicle to vehicle.
  • a serious drawback of these portable cellular phones is that their range is limited. This is due in large part to the limitations of the antenna of the portable units.
  • the portable vehicular cellular telephones are typically provided with an electrically shortened inductively loaded whip antenna referred to as a "rubber ducky.” When they are used with such an antenna in cars or trucks and the like, the range of these units, and their usefulness, is limited.
  • the modified rod antenna is a standard length AM/FM antenna provided with a coaxial trap positioned at a point removed from the lower end of the antenna by a distance equivalent to one and one- quarter wavelength of a signal in the cellular telephone frequency range, i.e., 821 to 896 megahertz (MHz).
  • the coaxial trap serves to isolate the upper portion of the antenna from the lower portion to form a cellular telephone antenna in the lower portion.
  • the trap does not significantly alter the effectiveness of the full-length antenna in the AM frequency range, i.e., 550 to 1,600 KHz or the FM frequency range, i.e., 88 to 108 MHz range.
  • the coaxial trap is formed from a length of conductive tubing having one end electrically connected to the rod at a specific location and spaced apart from the rod antenna by a dielectric layer.
  • a conductive coaxial sleeve is placed on the rod antenna in the approximate middle of the lower portion of the modified antenna rod, which is defined as the cellular telephone portion of the antenna.
  • This coaxial sleeve impedes the phase reversal encountered in cellular telephone antennas and, in that sense, perform the function of the helical coil used in prior art antennas.
  • the coaxial sleeve does not have the noise disadvantage associated with the helical coil and is of considerably smaller diameter than the helical coil of the prior art cellular telephone antennas.
  • the entire antenna, including the coaxial trap and the coaxial sleeve may advantageously be encased in a sleeve-like cover to give the antenna a pleasing appearance.
  • the combined AM/FM/cellular telephone antenna is preferably mounted on a fender or cowl of the automobile in the same manner an AM/FM antenna is typically mounted.
  • a coaxial connector is incorporated in the dashboard of the automobile which allows a portable telephone system to be connected to the more efficient combined AM/FM/cellular telephone antenna, thereby significantly enhancing the usefulness of the portable units in automobiles.
  • the portable telephone may be connected to the vehicle battery via a connector in the dashboard.
  • Applicants' combined AM/FM/cellular telephone antenna provides a better match to vehicular cellular phone systems than many prior art antennas and provides substantial improvements in gain over standard magnetic mount and glass mount cellular telephone antennas. Furthermore, with the antenna of the present invention, operation of the cellular phone does not create any discernable interference in AM/FM reception.
  • FIG. 1 is a representation of a combined AM/FM/cellular telephone antenna incorporating a coaxial trap and a helical coil;
  • FIG. 2 is an enlarged cross-sectional view of the coaxial trap of FIG. 1;
  • FIG. 3 is a AM/FM/cellular telephone antenna including an upper coaxial trap and a lower coaxial sleeve;
  • FIG. 4 is an enlarged cross-sectional view of the coaxial sleeve of
  • FIG. 3
  • FIG. 5 is a representation of the antenna of FIG. 3 encased in a sleeve-type cover; and FIG. 6 is a circuit diagram representation of a diplexer circuit connected to the antenna of FIG. 1 or FIG. 3.
  • FIG. 1 is a representation of an automotive antenna incorporating principals of the invention.
  • the antenna 100 includes an antenna rod 101 consisting of an upper portion 102, shown in a partial breakaway representation, and a lower portion 103.
  • the full-length of the antenna rod 101 is on the order of 30 to 36 inches which is generally the preferred length for an AM/FM antenna.
  • the upper portion 102 and the lower portion 103 are divided by a high-frequency, coaxial trap 105.
  • the trap 105 presents a high impedance, essentially open circuit, to signals in the cellular telephone frequency range and serves to impede the flow of current in the cellular frequency range from the upper portion 102 of the antenna rod 101 to the lower portion 103.
  • the coaxial trap 105 does not substantially effect the current flow in the rod 101 in the AM/FM frequency range. In this manner, the coaxial trap 105 serves to define a cellular telephone antenna, in the lower portion 103, as an integral part of an AM/FM antenna.
  • the lower portion 103 of the antenna 100 includes a helical coil 107 such as is typically used in cellular telephone antennas to minimize the effects of phase reversal.
  • FIG 1 further shows a conventional antenna mount 115 which threadably engages a lower housing 110 for mounting the antenna rod 101 to the housing 110.
  • the housing 110 is mounted to fender 114 in a conventional manner by means of a threaded mounting ring 108.
  • the feed point 106 of the antenna rod 101 at the lower end thereof is electrically connected to a diplexer network 109 contained within the housing 110 and from which emanate a pair of conductors 116, 117 for connection to a cellular telephone and a AM-FM radio, respectively.
  • FIG. 2 is an enlarged, cross-sectional view of the coaxial trap 105.
  • the trap 105 has an electrical length of 1/4 wavelength in the cellular frequency range, e.g., 850 MHz, and includes a thin-walled, cylindrically shaped sleeve section 125.
  • the sleeve section 125 includes a lower wall 123, having a central opening 124, and is mounted to the antenna rod 101 at its lower end by means of a collar 126 and a conventional screw (not shown in the drawing).
  • the collar and screw provide electrical contact between the sleeve section 125 and the rod 101.
  • the space between the wall of the sleeve section 125 and the rod 101 is preferably filled with a dielectric 127 such as Teflon or other suitable dielectric.
  • the sleeve section 125 may be constructed of copper or other suitable conductive material such as steel.
  • the walls of the sleeve section 125 are 0.012 inches thick, the outer diameter is approximately 5/16 inches, and the space between the sleeve section and the rod is filled with a dielectric having a dielectric constant of approximately 2.
  • the coaxial trap at its upper end, presents essentially an open circuit to signals in the cellular telephone frequency range.
  • the trap 105 is preferably mounted on the antenna rod 101 such that its upper edge is at a distance equivalent to an electrical length of one and one-quarter wavelengths in the cellular telephone frequency range from the ground plane, e.g., the fender 114.
  • Shown in FIG. 1 is a dashed line 119 representing current distribution in the cellular telephone range with current essentially at 0 at the upper edge of the trap 105 and a standard current distribution between that point and the ground plane of fender 114.
  • the antenna shown in FIG. 3 includes a coaxial sleeve 120 which replaces the helical coil 107 of FIG. 1.
  • the typical cellular telephone antenna has an electrical length of one and one-quarter wavelengths in the corresponding frequency range for improved gain.
  • the prior art helical coil 107 serves to reduce the effects of phase reversal at the approximate midpoint of the antenna, which would otherwise occur tending to cancel the groundwave signal and negatively affecting antenna performance. Even with the addition of the coil, a relatively small phase reversal of the current in the cellular frequency range does tend to occur, as indicated by line 119 in FIG. 1. However, this does not significantly affect signal strength in the antenna of FIG. 3.
  • the coaxial sleeve 120 is used instead of a helical coil and performs the function of reducing the effect of phase reversal and the accompanying signal degradation.
  • the coaxial sleeve produces a phase shift by electrically adding one-half wavelength to the antenna.
  • the coaxial sleeve 120 which is constructed in a manner analogous to trap 105, is shown in greater detail in FIG. 4.
  • the coaxial sleeve 120 is shown in greater detail in FIG. 4.
  • the sleeve 120 comprises a thin-walled tubular sleeve section 121 which is open at its lower edge and comprises an upper wall 128 having an opening 131 extending over antenna rod 101.
  • the sleeve 120 is mounted to the antenna rod 101 by means of a collar 122 and a conventional screw (not shown in the drawing). The collar and screw provide electrical contact with the antenna rod 101 at the upper end of the coaxial sleeve 120.
  • the space between the antenna rod 101 and the wall of the sleeve section 121 is preferably filled with a dielectric 130.
  • the sleeve section 121 may be made of copper or other suitable conductor.
  • the sleeve section 121 is made of copper and has a thickness on the order of 0.012 inches and an outer diameter of approximately 5/16 inches.
  • the dielectric material has a dielectric constant of approximately 2.
  • the coaxial sleeve 120 has a physical length of approximately one-quarter wavelength and an electrical length equal to one-half wavelength in the cellular frequency range and the lower edge of coaxial sleeve 120 is removed from the antenna feed point 106, at the upper end of the housing 110 by a distance equivalent to an electrical length equal to one- quarter wavelength in the cellular telephone frequency range.
  • FIG. 3 shows the antenna feed point 106 positioned above the fender 114 by a distance, e.g., on the order of 3 inches.
  • This position of the feed point above fender 114 was empirically determined to provide improved antenna operation.
  • the position of the feed point and the diplexer network relative to the ground plane provided by the vehicle may be adjusted for optimum operation on different vehicle types.
  • the antenna may readily be adjusted in the vertical direction by adjusting the position of the housing 110 in the threaded mounting ring 108.
  • Line 129 in FIG. 3 shows a current distribution similar to that shown by line 119 in FIG. 1.
  • the coaxial sleeve 120 provides the same function of minimizing the effects of phase reversal as the prior art helical coil 107. However, the coaxial sleeve 120 conveniently avoids the wind noise which accompanies such helical coil.
  • the coaxial trap 105 and the coaxial sleeve 120, together with the remainder of the antenna rod 101 may be conveniently encased in a sleeve-like cover or the like as depicted for example in FIG. 5.
  • the antenna rod 101 may be a standard stainless steel whip antenna and the cover 130 may be made of fiberglass or the like.
  • the cover serves for aesthetic purposes and is not required for proper operation of the antenna.
  • the cover is preferably tapered in the area above the coaxial trap 105.
  • FIG. 6 is a circuit diagram representation of the diplexer network 109 contained within the housing 110.
  • the diplexer circuit is connected to the antenna 100 by means of a conductor 150, which may, for example, be a short length of #18 or #20 conductor.
  • a self-resonant inductor 157 is connected between the antenna and the connection to an AM/FM radio. Because the frequency separation between cellular and AM/FM is relatively great, a self- resonant inductor, resonant at 850 MHz, will present a relatively low impedance in the AM/FM range (approximately 100 MHz) and present a high impedance at the cellular frequency (approximately 850 MHz).
  • the inductor 157 has an inductance of approximately 25 nanohenrys.
  • An open circuit stub 159 is connected to the conductor 117 between the coil 157 and the connection to the AM/FM radio.
  • the open circuit stub 159 has an electrical length equivalent to one-quarter of the wavelength at 850 MHz, e.g., a length on the order of 2.4 inches, using a teflon dielectric.
  • the open circuit stub provides a reflecting termination at the selected frequency, having a very low impedance at the one-quarter wavelength.
  • Other standard circuit arrangements may be provided to isolate the AM/FM radio from the cellular frequency signal.
  • a capacitor 155 presenting essentially an open circuit in the AM/FM frequency range, is connected in series between the conductor 150 and the connection to a cellular telephone.
  • the capacitor 155 may, for example, have a value of 3.3 picofarads.
  • the capacitor 155 is connected to conductor 150 via a relatively short conductor section 154 having an inductance of 10 nanohenrys will tend to resonate at cellular frequencies, thereby presenting a very low impedance at those frequencies while offering a high impedance to AM/FM frequencies.
  • a coaxial connector 152 is provided to allow a portable cellular phone to readily connected to and disconnected from the antenna.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Support Of Aerials (AREA)
  • Details Of Aerials (AREA)

Abstract

Système (100) combiné d'antenne de téléphone cellulaire AM/FM qui comporte une tige (101) d'antenne AM/FM de longueur standard dotée d'un filtre coaxial (105) monté sur la tige d'antenne à une position éloignée du plan du sol (114) d'une distance (103) égale à une longueur d'onde et quart dans la gamme de fréquences cellulaires. Ledit filtre coaxial (105) qui comporte une douille cylindrique est monté sur la tige d'antenne et connecté électriquement à cette dernière à l'extrémité inférieure de la douille. La partie inférieure de la tige d'antenne, située au-dessous de la douille, est définie en tant qu'antenne de téléphone cellulaire et le filtre coaxial empêche le passage de courants dans la gamme de fréquences cellulaires de la partie supérieure à la partie inférieure de l'antenne. Une douille coaxiale (120) est montée sur la partie inférieure de l'antenne. Ladite douille sert à réduire au minimum les effets de l'inversion de phase dans l'antenne de fréquences de téléphone cellulaire.
PCT/US1995/008528 1994-07-08 1995-07-07 Systeme combine d'antenne de telephone cellulaire am/fm WO1996002075A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US27305194A 1994-07-08 1994-07-08
US08/273,051 1994-07-08

Publications (1)

Publication Number Publication Date
WO1996002075A1 true WO1996002075A1 (fr) 1996-01-25

Family

ID=23042341

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/008528 WO1996002075A1 (fr) 1994-07-08 1995-07-07 Systeme combine d'antenne de telephone cellulaire am/fm

Country Status (1)

Country Link
WO (1) WO1996002075A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2321342A (en) * 1997-01-16 1998-07-22 Andrew Jesman Cellular telephone antenna
WO1998058422A1 (fr) * 1997-06-17 1998-12-23 Samsung Electronics Co., Ltd. Antenne a double bande pour communications mobiles
EP1451896A1 (fr) * 2001-10-31 2004-09-01 Young Joon Kim Antenne nx destinee a la communication mobile
GB2416922A (en) * 2004-07-30 2006-02-08 Motorola Inc Elongate antenna with a coaxial portion arranged for multi-frequency operation
EP2056401A1 (fr) * 2007-11-05 2009-05-06 Mitac Technology Corp. Antenne monopôle à double bande chargée sur une ligne de transmission

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725942A (en) * 1965-04-22 1973-04-03 Allen Elect Equip Vehicle-mounted antenna and coupling circuit therefor
US3981017A (en) * 1975-03-31 1976-09-14 Motorola, Inc. Center fed vertical gain antenna
US4085405A (en) * 1976-11-09 1978-04-18 Mhz Enterprises, Inc. Antenna matching network
US4375642A (en) * 1980-09-25 1983-03-01 Robert Bosch Gmbh Rod antenna, particularly for mobile FM signal transducing applications
US4509056A (en) * 1982-11-24 1985-04-02 George Ploussios Multi-frequency antenna employing tuned sleeve chokes
US4675687A (en) * 1986-01-22 1987-06-23 General Motors Corporation AM-FM cellular telephone multiband antenna for motor vehicle
US4721965A (en) * 1986-01-22 1988-01-26 General Motors Corporation AM-FM-cellular telephone multiband antenna for motor vehicle
US5089829A (en) * 1989-12-22 1992-02-18 Yokowo Mfg. Co., Ltd Antenna device shared by three kinds of waves
US5248988A (en) * 1989-12-12 1993-09-28 Nippon Antenna Co., Ltd. Antenna used for a plurality of frequencies in common

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725942A (en) * 1965-04-22 1973-04-03 Allen Elect Equip Vehicle-mounted antenna and coupling circuit therefor
US3981017A (en) * 1975-03-31 1976-09-14 Motorola, Inc. Center fed vertical gain antenna
US4085405A (en) * 1976-11-09 1978-04-18 Mhz Enterprises, Inc. Antenna matching network
US4375642A (en) * 1980-09-25 1983-03-01 Robert Bosch Gmbh Rod antenna, particularly for mobile FM signal transducing applications
US4509056A (en) * 1982-11-24 1985-04-02 George Ploussios Multi-frequency antenna employing tuned sleeve chokes
US4675687A (en) * 1986-01-22 1987-06-23 General Motors Corporation AM-FM cellular telephone multiband antenna for motor vehicle
US4721965A (en) * 1986-01-22 1988-01-26 General Motors Corporation AM-FM-cellular telephone multiband antenna for motor vehicle
US5248988A (en) * 1989-12-12 1993-09-28 Nippon Antenna Co., Ltd. Antenna used for a plurality of frequencies in common
US5089829A (en) * 1989-12-22 1992-02-18 Yokowo Mfg. Co., Ltd Antenna device shared by three kinds of waves

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HALL et al., "The ARRL Antenna Book", 1983, pp. 5-17 - 5-22. *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2321342A (en) * 1997-01-16 1998-07-22 Andrew Jesman Cellular telephone antenna
WO1998058422A1 (fr) * 1997-06-17 1998-12-23 Samsung Electronics Co., Ltd. Antenne a double bande pour communications mobiles
EP1451896A1 (fr) * 2001-10-31 2004-09-01 Young Joon Kim Antenne nx destinee a la communication mobile
EP1451896A4 (fr) * 2001-10-31 2005-07-27 Young Joon Kim Antenne nx destinee a la communication mobile
GB2416922A (en) * 2004-07-30 2006-02-08 Motorola Inc Elongate antenna with a coaxial portion arranged for multi-frequency operation
GB2416922B (en) * 2004-07-30 2009-03-04 Motorola Inc Antenna for use in a mobile radio communication device
EP2056401A1 (fr) * 2007-11-05 2009-05-06 Mitac Technology Corp. Antenne monopôle à double bande chargée sur une ligne de transmission
US7804459B2 (en) 2007-11-05 2010-09-28 Getac Technology Corporation Transmission line loaded dual-band monopole antenna

Similar Documents

Publication Publication Date Title
US4675687A (en) AM-FM cellular telephone multiband antenna for motor vehicle
US6107972A (en) Multiband antenna system
US4721965A (en) AM-FM-cellular telephone multiband antenna for motor vehicle
US4791426A (en) Active antenna in the rear window of a motor vehicle
CA1319975C (fr) Antenne telescopique pour vehicule
EP0360594B1 (fr) Antenne à boucle pour voiture automobile
US5072230A (en) Mobile telescoping whip antenna with impedance matched feed sections
US10811760B2 (en) Multi-band window antenna
US6297711B1 (en) Radio frequency multiplexer for coupling antennas to AM/FM/WB, CB/WB, and cellular telephone apparatus
US20060170610A1 (en) Antenna system for remote control automotive application
US5610619A (en) Backlite antenna for AM/FM automobile radio having broadband FM reception
US5311201A (en) Multi-band antenna
US4968984A (en) Antenna unit for a vehicle
US5668564A (en) Combined AM/FM/cellular telephone antenna system
WO2009004449A2 (fr) Système d'antenne pour une application de commande à distance pour automobile
US6384696B1 (en) Multiplexer for sorting multiple signals from an antenna
WO1996002075A1 (fr) Systeme combine d'antenne de telephone cellulaire am/fm
US20020020034A1 (en) Windshield wiper arm
US5790079A (en) Backlite antenna for AM/FM automobile radio
JPH11330832A (ja) 車両用ガラスアンテナ装置
JPH042002B2 (fr)
JP3181075B2 (ja) 移動体用アンテナ
US4223314A (en) AM-FM and CB antenna
US6396365B1 (en) Multiplexer for cellular telephone
US6943740B1 (en) Methods and systems for concealing antennas

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA JP MX

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA