Dual-band PIFA using resonated loop feed structure

Abstract

Described is a simple method for exciting a planar inverted-F antenna (PIFA) in order to achieve dual-band operation. The conventional loop feed of a PIFA, formed by the feeding and shorting conductors, is modified by inserting a capacitor into the feeding conductor. The proposed feeding method can provide a wide impedance bandwidth (VSWR = 1.5:1) for 2.45 and 5.5 GHz WLAN applications, as well as a small antenna element size.