Mobile phone antenna with improved impedance-matching circuit

Claim 1

An antenna structure for mobile phones, comprising: an antenna stem, a swivel joint, a high-frequency connector and an impedance-matching member; said swivel joint including an antenna-mounting base, a joint-fastening base and an outer protection sleeve, said antenna-mounting base having an upper end and a lower end; said antenna stem being adapted to be fastened to the upper end of said antenna-mounting base, wherein the bottom end of said antenna-mounting base being adapted to be inserted into said joint-fastening base, and both said antenna mounting base and said joint-fastening base being mounted inside said outer protection sleeve, said outer protection sleeve containing retaining means to prevent said antenna mounting base and said joint-fastening base from being disengaged from each other; said high-frequency connector containing an insulation collar and a center-needle seat fixedly mounted therein, said center-needle seat being mounted on top of said insulation collar which insulates said center-needle seat from said high-frequency connector, said center-needle seat having a mounting hole formed on top thereof, said high-frequency connector further containing a sleeve wall for threadably sleeving about said protection sleeve; said impedance-matching member having an upper end and a lower end; the upper end of said impedance-matching member being fixedly attached to the bottom of said joint-fastening base, while the lower end thereof being inserted into said mounting hole on said center-needle seat; the lower end of said antenna-mounting base being shaped like a cylindrical stud having a circumferential retaining groove for engaging with said joint-fastening base and a circumferential flange on top thereof for engaging with said outer protection sleeve via said retaining means; said joint-fastening base having a plurality of vertical slots on its upper portion to provide contractability thereof and allow said joint-fastening base to pivotably engage with said antenna-mounting base, a mounting hole on its lower portion for receiving said impedance-matching member, and a plurality of vertical slip-proof threads on the outer surface thereof to prevent slipping and rotating with respect to said protection sleeve; said impedance-matching member being shaped like a spring and having a pre-determined electric characteristic whereby said impedance-matching member and said sleeve wall of said high-frequency connector form a predetermined electrostatic capacitance to facilitate high frequency transmission.