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 mm 2 ) 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.