A novel monopole antenna, constructed easily, by folding a simple metal plate, is presented. The folded metal-plate monopole antenna shows a compact size of 10 x 10 x 70 mm(3) and has three wide impedance bandwidths at about 0.9, 2.0, and 5.0 GHz thus covering the operating bandwidths of most of the present-day mobile communication systems (AMPS, GSM, DCS, PCS, and UMTS) and the WLAN systems in the 2.415.215.8-GHz bands. With the antenna performance obtained, the proposed antenna is suitable for application in a PDA phone for both mobile communications and WLAN applications. (C) 2003 Wiley Periodicals, Inc.