Variable length whip with helix antenna system

摘要

An antenna system for a communication device. A whip antenna is surrounded by a helical antenna. A switch couples the helical antenna to the signal source when the whip antenna is in a retracted position. The whip antenna is comprised of an upper conductive portion, a lower conductive portion, and a dielectric portion which isolates the upper and lower conductive portions from each other. A conductive sleeve member surrounds the whip antenna and is slidably mounted thereon. In a first embodiment, when the whip antenna is extended, the conductive sleeve member slides over the dielectric portion, coupling the upper and lower conductive portions together. As the whip antenna is retracted, the helical antenna pushes the conductive sleeve member to the top end of the whip antenna, isolating the whip antenna from the helical antenna. In a second embodiment, the helical antenna is an integral part of the conductive sleeve member.