Antenna systems having capacitively coupled internal and retractable antennas and wireless communicators incorporating same

摘要

Antenna systems for use within wireless communication devices such as radiotelephones are provided and include an internal multi-frequency band antenna and an elongated antenna member that is retractable. The elongated antenna member is extendible from the housing of a communications device so as to have an extended position and a retracted position. The elongated antenna member includes an elongated conductive element that is capacitively coupled with the multi-frequency band antenna when the elongated antenna member is in the extended position. The multi-frequency band antenna is electrically isolated from the elongated conductive element when the elongated antenna member is in the retracted position. When the elongated antenna member is in an extended position, the elongated conductive element is configured to resonate as a half-wave monopole antenna when the internal antenna resonates within a first frequency band. The elongated conductive element is configured to resonate as a full-wave monopole antenna when the internal antenna resonates within a second frequency band.