Coupled‐fed small‐size PIFA for penta‐band folder‐type mobile phone application

A small‐size planar inverted‐F antennas (PIFA) for penta‐band operation in the folder‐type mobile phone is presented. The PIFA occupies a small volume of 2.1 cm 3 only. Instead of using the conventional direct contact feed, the proposed PIFA uses a coupling feed, which allows the antenna in its open state or talk condition to generate a dual‐resonance lower band of bandwidth 300 MHz (780–1080 MHz, 3:1 VSWR or 6‐dB return loss) to cover GSM850/900 operation. In addition, the PIFA can also generate a very wide upper band of bandwidth 925 MHz (1368–2293 MHz) to cover GSM1800/1900/UMTS operation. When the mobile phone is in its close state or standby condition, the obtained lower and upper bands can still cover GSM850/900/1800/1900/UMTS penta‐band operation with impedance matching better than 6:1 VSWR or 3‐dB return loss, which is acceptable for the mobile phone in standby condition for practical applications. Details of the proposed PIFA and the obtained results are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 18–23, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23980