Patent ID: 6366247
Filing Date: 2002-04-02
Classification: H01Q,H04B

Abstract:
An antenna device comprising:a first antenna element provided so as to be freely retracted or extended; a second antenna element; an unbalanced transmission line for supplying power to the first and second antenna elements; balanced-to-unbalanced transform means for performing balanced-to-unbalanced transform between the unbalanced transmission line and the first and second antenna elements; and connection means for electrically connecting the first and second antenna elements to the balanced-to-unbalanced transform means when the first antenna element is retracted and electrically connecting at least the first antenna element to the balanced-to-unbalanced transform means when the first antenna element is extended, wherein the first and second antenna elements are operated as antennas by supplying power to the first and second antenna elements from the unbalanced transmission line through the balanced-to-unbalanced transform means when the first antenna element is retracted; and the first antenna element is operated as an antenna by supplying power to at least the first antenna element from the unbalanced transmission line through the balanced-to-unbalanced transform means when the first antenna element is extended.