Due to the recent rapid development in wireless communication, all mobile communications system or network are now operating with more than one frequency band; an example is the wireless local area network (WLAN) that is designed for three modes operation in the 2.4/5.2/5.8 GHz bands. Within all the antennas design for such network, the planar inverted-F antenna (PIFA) design is considered to be one of the most prominent candidates employed commonly by the industry. From the open-literature, in depth studies on improving the impedance bandwidth , and the effects of ground plane size on PIFA performance  are discussed in detail. To achieve dual band operation on a traditional PIFA, conventional methods such as slot loading the top radiating element  is recommended, and if a further size-reduction is required, folding the top radiating element is also proposed . Although the combination of both slot loading and folding techniques as demonstrated in  have a wideband operation (4.85 to 11.5 GHz) which allows 5.2/5.8 GHz WLAN and Satellite Communication (8.175 to 10 GHz) operations, however, it is unable to operate at the basic 2.4 GHz WLAN band. Furthermore, even though a multi-band operation is demonstrated by applying the combined techniques , its quad-band operation (GSM, DCS, 2.4/5.2 GHz WLAN) can only be achieved by loading three U-shaped slots onto the top radiating element, with the absent of 5.8 GHz WLAN band.