| 摘要 |
A dual frequency antenna comprises a housing 2 having a base 4 adapted to attachment to a vehicle windscreen. Antenna elements 7A,7B forming dipoles are supported within the housing 2 to define an included angle of approximately 140{ (angles between 120 and 180 are also described). The elements 7A, 7B comprise dipole elements 21, 22. A coaxial cable 13 having inner and outer conductors coupled to the antenna elements 7A and 7B at their apex is routed in spaced relation to the element 7A connected to the inner conductor, in such a manner that currents tending to be induced in the outer conductor of the coaxial cable are canceled as a result of the proximity of the cable 2 to the element 7A. This enables the coaxial cable to be matched to the impedance of the antenna. The antenna is particularly suited for use with mobile phones and the like. |
