A Compact Wideband Modified Planar Inverted $F$ Antenna (PIFA) for 2.4/5-GHz WLAN Applications

A compact wideband modified planar inverted F antenna (PIFA) with two shorting strips for 2.4/5.2-GHz wireless local area network (WLAN) operations is presented. As a starting point, two-branch strip lines derived from the dipole antenna structure are used to achieve the desired resonant frequency. One of them is connected to two shorting strips with the different length and width, and those strips generate additional resonant modes. A wideband characteristic can be optimized by tuning the parts of two shorted patches and size of each strip line segment. The proposed antenna has a low profile and can easily be fed by a 50-Omega coaxial cable. In addition to covering 2.4- and 5.2-GHz band, a wide impedance bandwidth from 2.94 to 5.82 GHz (|S11|<-10 dB, about 69% centered at 4.14 GHz) is obtained. The measured maximum radiation gains at the frequencies of 2.44, 4.14, and 5.2 GHz are about 1.6, 3.8, and 2.5 dBi, respectively. The proposed antenna is suitable for the multiband operations, covering 2.4/5.2-GHz WLAN operation