SMALL-SIZE COUPLED-FED SHORTED T-MONOPOLE FOR INTERNAL WWAN ANTENNA IN THE THIN-PROFILE MOBILE PHONE

摘要

A coupled-fed shorted T-monopole with a small size of 15×26 mm~2 (390 mm~2) printed on the system circuit board of the mobile phone for WWAN operation is presented. By using a simple inverted-L feeding strip to capacitively excite the shorted T-monopole, two wide operating bands at about 900 and 1900 MHz, respectively, to cover GSM850/900 and GSM1800/1900/UMTS operations are obtained. The antenna is an all-printing structure, with no external matching circuit on the system circuit board or lumped circuit elements embedded in the antenna required for size reduction or bandwidth enhancement. The antenna is hence easy to fabricate at low cost and is especially suited for thin-profile mobile phone applications. The occupied area (less than 400 mm~2) of the antenna printed on the system circuit board of the mobile phone in this study is among the smallest for the internal uniplanar printed antenna capable of penta-band WWAN operation that have been reported. Details of the proposed antenna are described, and the obtained results, including its SAR (specific absorption rate) study, are presented and discussed.