Printed λ/8-PIFA for internal penta-band mobile phone antenna

A small-size printed PIFA operated at its lambda/8 mode as the fundamental mode for achieving WWAN (wireless wide area network) operation in the mobile phone is presented. The proposed PIFA has a simple structure of comprising two radiating strips of length about lambda/8 at 900 MHz and is fed using a coupling feed. Two lambda/8 modes are generated by the two radiating strips and occur at close frequencies at about 900 MHz to form a wide lower band to cover GSM850/900 operation. The two radiating strips also generate two lambda/4 modes at about 1900 MHz to form a wide upper band for GSM1800/1900/UMTS operation. Penta-band WWAN operation is hence achieved, yet the proposed PIFA only occupies a small printed area of 15 times 31 mm² or 465 mm² on the system circuit board of the mobile phone. Details of the proposed PIFA are presented. The SAR (specific absorption rate) and HAC (hearing aid compatibility) results for the proposed PIFA are also analyzed.