Patent ID: 6211829
Filing Date: 2001-04-03
Classification: H01Q

Abstract:
An antenna device for a radio communication device comprising:an essentially cylindrically configured radiator surrounded by dielectric material for minimizing coupling, said essentially cylindrically configured radiator mounted on and coupled to said radio communication device;an extendable elongated radiator movable to an extended position and to a retracted position;a switching device for coupling said extendable elongated radiator, when in said extended position, to said radio communication device;said essentially cylindrically configured radiator having an opening, and said opening extending axially through said essentially cylindrically configured radiator;said extendable elongated radiator being movably mounted through said opening of said essentially cylindrically configured helical radiator; whereinsaid extendable elongated radiator, when in the retracted position, extends inside said essentially cylindrically configured radiator in order to reduce a total length of said antenna device, and at least one of the properties length, geometry and surrounding dielectric material of said essentially cylindrically configured radiator is selected so as to obtain a compensating capacitive/inductive load on the essentially cylindrically configured radiator at least partially compensating a first capacitive/inductive load on the essentially cylindrically configured radiator resulting from the presence of the elongated radiator inside said essentially cylindrically configured radiator in the retracted position.