Small‐size microstrip‐coupled printed PIFA for 2.4/5.2/5.8 GHz WLAN operation in the laptop computer

With a microstrip-coupled feed, a small-size (9 × 10 mm2) printed PIFA capable of generating two wide bands to cover WLAN operation in the 2.4 GHz and 5.2/5.8 GHz bands for laptop computer application is presented. The PIFA is easily printed on a thin, inexpensive FR4 substrate at low cost. Although, the printed PIFA provides a resonant path of about 20 mm only (about 0.16 wavelength at 2.4 GHz), far less than the required resonant length for the conventional quarter-wavelength mode excitation and hence showing large inductive reactance at around 2.4 GHz, the applied microstrip-coupled feed in this study effectively compensates for it to result in a resonance (zero reactance) at about 2.4 GHz. A desired resonant mode for covering 2.4 GHz WLAN operation is thus excited for the proposed small-size printed PIFA. In addition, a higher-order resonant mode at about 5.5 GHz is also generated to cover the 5.2/5.8 GHz WLAN operation. Details of the proposed PIFA are described, and results of the fabricated prototype are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2072–2076, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24582