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
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
• • 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
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
  • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
  • H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas
• • 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
  • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
• • 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
  • H01Q5/364—Creating multiple current paths
  • H01Q5/371—Branching current paths
• • 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
  • H01Q9/44—Resonant antennas with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions
  • H01Q9/46—Resonant antennas with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions with rigid elements diverging from single point

Definitions

• the present invention relates generally to antennas for mobile communication devices. More particularly, the present invention relates to a multiple band, multiple branch antenna.
• GSM Global System for Mobile Communications
• Dual band antenna designs are known.
• the Japanese patent (6-37531) discloses a helix which contains an inner parasitic metal rod.
• the antenna can be tuned to dual resonant frequencies by adjusting the position of the metal rod.
• the band width for this design is too narrow for use in cellular communications.
• Dual band printed monopole antennas are known in which dual resonance is achieve by the addition of a parasitic strip in close proximity to a printed monopole antenna. While such an antenna has enough bandwidth for cellular communication, it requires the addition of a parasitic strip.
• Moteco AB in Sweden has designed a coil matching dual band whip antenna and coil antenna, in which dual resonance is achieve by adjusting the coil matching component ( l ⁇ ⁇ for 900 MHZ and 1 ⁇ for 1800 MHZ). While this antenna has relatively good band width and radiation performances, its length is only about 40mm.
• a non uniform helical dual band antenna which is relatively small in size is disclosed in Applicant's copending , commonly assigned application entitled “Multiple Band Non-Uniform Helical Antennas", serial number 08/725,507, the entirety of which is incorporated by reference.
• an extended whip antenna has a higher efficiency when the phone is relatively close to a human head.
• Typical dual band extendable whip antennas such as those mentioned above, require a complicated matching network to match the whip antenna impedance to the two bands within 50 ohms.
• a dual band retractable antenna is disclosed in Applicant's copending, commonly assigned application entitled “Retractable Multi-Band Antennas", serial number 08/725,504, the entirety which is incorporated by reference.
• Such an antenna requires two ports, one for a helical antenna and another for a whip antenna. A means for switching between the ports for the different modes is required.
• a multiple mode portable communication device it would be desirable for a multiple mode portable communication device to have an efficient multiple band antenna.
• Conventional dual band helical antennas such as those described above have certain disadvantages. For example, mechanical production tolerances can change the resonant frequencies, particularly at higher bands. Also, it can be relatively difficult to provide a sufficient coupling for dual band parasitic coupling extendable antennas because the distance between a base antenna and the extendable whip can be different at different bands.
• the present invention overcomes the above-described problems, and achieves additional advantages, by providing a multiple band, multiple branch antenna which can be tuned to multiple resonant frequencies.
• the multiple resonances for the antenna are achieved by providing variations in the printed pattern of the antenna branches.
• Each branch of the antenna can be printed on a relatively thin plastic film, and can be rolled into a cylinder shape.
• the branches can be formed by etching patterns on a plastic member having a cylindrical or other suitable shape.
• the multiple branch antenna of the present invention achieves resonance at different frequencies without a matching network. If the antenna branches are formed by printing, mechanical tolerance problems are avoided.
• the geometries of the branches can be varied to allow increased design freedom.
• FIG. 1 is a diagram showing a multiple branch antenna implementing the principles of the present invention
• FIG. 2 is a diagram of a printed antenna branch according to an embodiment of the present invention.
• FIG. 3 is a diagram showing a method for manufacturing an antenna according to the present invention.
• FIG. 4 is a graphical representation of measured return loss for an antenna assembly including a multiple branch antenna according to the invention.
• a central principle of the present invention is that different branches of the multiple band antenna are resonant at different frequencies.
• This principle is represented in FIG. 1, which shows a multiple branch antenna having first and second branches 10 and 12.
• the antenna branches are connected to a common port 14 for exchanging signals between the antenna branches and the transceiver circuitry of a portable communications device 16.
• the first branch 10 is of a length and construction so as to be resonant at frequencies in a first band
• the second branch 12 is of a length and construction so as to be resonant at frequencies in a second band.
• the first band is the GSM band and the second band is the DCS band.
• the first branch 10 is approximately 1/4 wavelength of a GSM signal
• the second branch 12 is approximately 1/4 wavelength of a DCS signal.
• the antenna is tuned, for example at the time of manufacture, to an impedance of approximately 50 ⁇ for both bands. If the antenna is so tuned, no impedance matching circuitry is required between the antenna and the port 14.
• FIG. 2 an exemplary antenna branch according to an embodiment of the invention is shown.
• the antenna branch is comprised of a relatively thin, flexible dielectric film 20 and a strip antenna formed by a meandering metal line 22.
• the metal line can be formed by printing, etching, or other suitable method.
• the printed film can be rolled into a generally cylindrical shape for use as an antenna branch, as shown in FIG. 3.
• the cylinder could be partially open or completely closed depending upon antenna design considerations.
• the bandwidth of the antenna can be varied by varying the diameter of the cylinder.
• the antenna branches can be formed in shapes other than a cylinder, and different branches can have different geometries (for example, elliptical), depending upon design considerations.
• the metal line 22 can also be etched directly onto a dielectric cylinder. The use of different geometries and manufacturing methods allow increased design freedom.
• the meandering metal line 22 is preferably varied between the antenna branches such mat the different antenna branches are resonant at different frequencies.
• multiple resonances in multiple branches can be achieved by selecting appropriate strip dimensions and patterns for each branch.
• the antenna branches are similar to monopole antennas, and have relatively high efficiency when used in a portable, hand-held communication device such as a mobile telephone.
• the dual resonances of a typical dual band helical antenna are achieved by changing pitch angle or other helical parameters. Because the resonant frequencies in a helical antenna will also be dependent upon the mechanical tolerances of the helical parameters, the multiple branch antenna of the present invention provides a significant advantage. More particularly, the printed multiple branch antenna according to the present invention significantly reduces the likelihood of mechanical tolerance problems because the height of the antenna can be easily adjusted by changing the strip line pattern or dimensions.
• the antenna of the present invention is particularly suitable as a multiple mode base antenna for the parasitic extendable dual band antenna disclosed in Applicant's copending, commonly-assigned application entitled “Multiple Band Telescope Type Antenna for Mobile Phone", the entirety of which is incorporated by reference.
• the multiple mode, multiple branch antenna of the present invention allows the coupling distance between whip antenna and the base antenna to be easily adjusted. This provides a significant advantage over known dual band helical antennas.
• FIG. 4 a graphical representation of measured return loss for an antenna assembly including a multiple band, multiple branch antenna according to the present invention is shown.
• FIG. 4 shows the return loss in dB for different frequencies.
• the diagram indicates a first peak corresponding tot he GSM frequency band, a second peak corresponding to the DCS frequency band, and a third, shallower peak corresponding to the PCS frequency band.
• a suitable antenna accordmg to the present invention can be designed to operate in two or more bands corresponding to GSM, DCS, PCS, or other frequency bands. Radiation pattern tests of the antenna according to the present invention show that the antenna achieves performance similar to a helical antenna, but the with a broader band width.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Details Of Aerials (AREA)
• Support Of Aerials (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Transceivers (AREA)

Priority Applications (5)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26827315

Family Applications (1)

Country Status (8)

Cited By (20)

Families Citing this family (7)

Citations (6)

• 1998
  • 1998-10-16 IL IL13584898A patent/IL135848A0/xx unknown
  • 1998-10-16 JP JP2000518424A patent/JP2001522152A/ja active Pending
  • 1998-10-16 KR KR1020007004525A patent/KR100602539B1/ko not_active IP Right Cessation
  • 1998-10-16 AU AU96579/98A patent/AU9657998A/en not_active Abandoned
  • 1998-10-16 CN CN98812744A patent/CN1290412A/zh active Pending
  • 1998-10-16 WO PCT/SE1998/001865 patent/WO1999022420A1/en active IP Right Grant
  • 1998-10-16 EP EP98950573A patent/EP1025613A1/en not_active Withdrawn
  • 1998-10-29 TW TW087117928A patent/TW392376B/zh not_active IP Right Cessation

Patent Citations (6)

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