A PIFA-Type Varactor-Tunable Slim Antenna With a PIL Patch Feed for Multiband Applications

A novel varactor-tuned compact multiband slim antenna for covering the digital cellular system (DCS; 1710-1880 MHz), personal communication service (PCS; 1850-1990 MHz), Universal Mobile Telecommunications System (UMTS; 1900-2200 MHz), WiBro (2300-2390 MHz), and wireless LAN (WLAN; 5150-5350 and 5725-5850 MHz) bands is presented. The proposed antenna consists of a main patch and a planar inverted-L (PIL) patch with a feed line for the broadband characteristic. A varactor diode is attached to the radiating element for frequency shift. This antenna occupied in a total volume of 27 mm times 11 mm times 5 mm can be easily placed in commercial mobile handsets. The computer simulation technology (CST) microwave studio is used to design and optimize the antenna. We found good agreement between the simulated and measured results