Retractable antenna for a portable radio apparatus

摘要

An antenna which is suitable for use with a portable apparatus comprises a cylindrical core (11) fixed to a metal fixture at one end thereof, a ring spring disposed coaxially with the core on the other end portion of the core (11), a cap (14) formed with a through hole communicating with a central hole of the core (11) and covering the core (11) and the ring spring (15), and a rod antenna member (20) formed with a large-diameter top portion (lib) and a joint portion (26) on both ends thereof so as to be slidably fitted to the central hole of the core, therein a notch (26a) engaged with the ring spring (15) is formed at the top portion (11b) and the joint portion (26) of the rod antenna member (20), respectively. Preferably, the cylindrical core (11) is formed of an electrically insulating substance, and a first antenna portion is formed by disposing an antenna element on an outer circumference of the core (11).