Patent ID: 6414638
Filing Date: 2002-07-02
Classification: H01Q

Abstract:
An antenna for a radio telephone, comprising:a helical antenna having an electrical length of about &lgr;/4, wherein &lgr; is a wavelength of a service frequency, and having a basal end thereof, which is arranged on a wall of a case of the radio telephone, connected to a power supply component of the radio telephone; and a rod antenna extendable and retractable with respect to the case of the radio telephone through a hollow central portion of the helical antenna, with an electrical length of about 3&lgr;/8 and having inductive reactance; wherein a basal end of the rod antenna and a distal end of the helical antenna are electrically coupled in series by means of an electrostatic coupling portion having a capacitive reactance that cancels out the inductive reactance when the rod antenna is extended from the radio telephone case, and wherein a gap is formed between the basal end of said rod antenna and the distal end of said helical antenna when said rod antenna is being used, said gap being defined by a longitudinal space between the basal end of said rod antenna and the distal end of said helical antenna.