GSM850/900/1800/1900/UMTS coupled‐fed planar λ/8‐PIFA for internal mobile phone antenna

A coupled‐fed planar PIFA (planar inverted‐F antenna) operated in its one‐eighth wavelength (λ/8) mode, different from the traditional one‐quarter wavelength (λ/4) mode, as the fundamental mode for mobile phone application is presented. The proposed PIFA comprises two radiating strips, both of slightly different lengths and close to about λ/8 at 900 MHz. By incorporating the use of the coupling feed, a wide operating band formed by the two λ/8 modes is excited at about 900 MHz for the antenna to cover GSM850/900 operation. Two λ/4 modes are also generated at close frequencies to from a wide operating band centered at about 1950 MHz to cover GSM1800/1900/UMTS operation. The proposed antenna hence can cover GSM850/900/1800/1900/UMTS penta‐band operation for application in the mobile phone. In addition, the antenna has a simple structure and can be printed on a thin FR4 substrate of size 1.6 × 7 × 40 mm 3 as a surface‐mountable chip antenna. Details of the proposed antenna are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1091–1096, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24214