(19)
(11) EP 1 819 011 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
22.08.2007 Bulletin 2007/34

(43) Date of publication A2:
15.08.2007 Bulletin 2007/33

(21) Application number: 07108068.3

(22) Date of filing: 09.11.2004
(51) International Patent Classification (IPC): 
H01P 5/10(2006.01)
 H01Q 9/20(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LU MC NL PL PT RO SE SI SK TR
Designated Extension States:
AL HR LT LV MK YU

(62) Application number of the earlier application in accordance with Art. 76 EPC:
04256929.3 / 1655801

(71) Applicant: Research In Motion Limited
Waterloo, Ontario N2L 3W8 (CA)

(72) Inventors:
  • Qi, Yihong
    Waterloo Ontario N2T 2H3 (CA)
  • Jarmuszewski, Perry
    Guelph Ontario N2E 5W4 (CA)
  • Dullaert, Paul
    Kitchener Ontario N2M 4W9 (CA)

(74) Representative: Korenberg, Alexander Tal 
Kilburn & Strode 20 Red Lion Street
London WC1R 4PJ
London WC1R 4PJ (GB)

   


(54) Balanced dipole antenna


(57) A balanced dipole antenna (100) has a coaxial cable connected between a load or source and the left (101) and right (102) dipole arms to substantially eliminate common mode current and radiative coupling between the coaxial cable and the left and right dipole arms. The connection between the source/load coaxial cable and the left and right dipole arms is a symmetric balun (110) having a center branch that is an extension of the source/load coaxial cable, and left and right stubs. When the stubs are segments of coaxial cable, the outer conductors (105,125) of the left and right stubs of the symmetric balun are respectively coupled to the left and right dipole arms (101,102), and one of the inner conductors (106) of the left and right stubs is connected to the inner conductor of the center branch (116), while the other of the inner conductor (126) of the left and right stubs is connected to the outer conductor of the center branch (115). When the stubs are metallic, the inner conductor of the center branch is electrically connected to one of the left and right dipole arms, while the outer conductor of the center branch is electrically connected to the other of the left and right dipole arms. A sliding bar (108) at the base of the stubs electrically connects the outer conductors (105,125) of the left and right stubs and the center branch (115).







Search report