Low-profile coupled-fed printed PIFA for internal seven-band LTE/GSM/UMTS mobile phone antenna

A coupled-fed printed PIFA (planar inverted-F antenna) with a low-profile (10mm) for seven-band operation covering the LTE700/2300/2500, GSM850/900/1900, and UMTS 2100 bands in the mobile phone is presented. The proposed antenna comprises a driven T-monopole and two coupled folded-strips; one on the back of the system circuit board short-circuited to the system ground plane of the mobile phone directly and the other one is coplaner with the T-monopole short-circuited to the system ground through an inductance. The driven T-monopole and the strip which is coplaner with it contribute a wide band for the antenna´s upper band (1810-2690 MHz), whereas the folded-strip on the back of system circuit generates a resonant mode for the antenna´s lower band (698-960 MHz). The antenna´s two wide operating bands are achieved and controlled by tuning the width of the T-monopole strip, the gap between the shorting strip and the T-monopole, and the dimensions of the shorting branch on the back of the system circuit board. Details of the proposed antenna are described, and the obtained results are presented and discussed.