A low-profile folded planar monopole antenna for wireless communication

This paper presents a novel design far a low-profile planar monopole antenna. The proposed antenna is a rectangular planar monopole with folded end. Its total height is about 0.12 lambda(0) (the free-space wavelength of the lowest operating frequency of the antenna), which is lower than other corresponding designs. In this study, a shorting plate is added to the edge of the rectangular plate to decrease the lower frequency for impedance matching. Furthermore, the offset center feeding is used to increase the upper frequency. Experimental results obtained from the constructed prototype show that the impedance bandwidth covers DCS (1720-1880 MHz), PCS (1850-1990 MHz), UMTS (1920-2170 MHz), and ISM (2400-2484 MHz, 5725-5852 MHz) bands. Moreover, the measured monopole-like radiation patterns prove that the proposed antenna has omni-directional radiation in the azimuthal plane. These performances suggest that the proposed antenna is suitable for application in wireless communication systems. (C) 2003 Wiley Periodicals. Inc.