A single feed multi-band internal antenna for mobile communication terminals

In this paper, we describe a single feed multiple-bands internal antenna that is designed for mobile and wireless application. A planar inverted-F antenna (PIFA) is configured as the basic architecture. The multi-band is achieved by integrating a U-shape strip line and an inverted L radiator. The PIFA antenna produces the first resonant frequency at 2GHz band; the U-shaped strip line produces the second resonant frequency at 2.4GHz band; the inverted L radiator the third resonant frequency at 5.8GHz band. The designed antenna is small in size, simple in structure. Bandwidth is 26% at 2GHz with VSWR less than and equal to 2∶1. Bandwidth is about 7% at 5.8GHz with VSWR less than and equal to 2∶1. The designed antenna is band wide enough to support mobile and wireless scenarios of UMTS (3G) band from 1920MHz to 2170MHz; Bluetooth WLAN at 2.4GHz from 2.4GHz to 2.485GHz; and WLAN at 5.8GHz from 5.725GHz to 5.85GHz. The antenna was designed by MWS CST software and was validated by experimental measurement in terms of port parameters. Finally, the impedance characteristic and far-field radiation pattern are listed and illustrated in the paper.