Single Feed Compact Quad-Band PIFA Antenna for Wireless Communication Applications

In this paper, a novel compact single feed quad-band planar inverted F-antenna (PIFA) is presented. Two techniques to reduce the physical size are illustrated. First, we insert U-shaped slits within the antenna-radiating surface. This forces the current to flow around the obstacles hence, reducing the resonant frequency. This technique reduces the size by about 30% from the original PIFA. Second, a capacitive plate is loaded between the radiating surface and the ground plane. The size is reduced more to reach 55% of the original. The relation between the capacitance load value and the antenna size reduction ratio is studied. Using different U-shaped slits at different appropriate positions, multiple (dual, tri, and quad) band capabilities are realized. The four center frequencies are chosen to lie within the GSM band, DCS band, Bluetooth (IEEE802.11a) ISM band, and WLAN (IEEE802.11b) band, respectively. Foam dielectric substrate is used for rigid structure and easy shielding purposes. The reduced size and thin substrate thickness allow the design to be compatible with wireless and portable communication systems. Experimental measurements verify the design and simulation criteria.