This paper proposes and studies a monopole antenna with a parasitic plate for WLAN applications. In this design, a microstripline-fed rectangular patch creates a resonant mode at 3 GHz. Furthermore, a parasitic plate is added on the side of the ground plane to generate a dual-band operation of 2.39 to 2.91 GHz and 4.06 to 6.73 GHz. The overall size of the proposed antenna is only 26x40x0.8 mm3(WsubxLsubxH). The monopole antenna with a parasitic plate is calibrated for WLAN applications, which cover the bands from 2.4 to 2.48 and 5.15 to 5.825 GHz. This antenna has the advantage of compact size, simple structure and good radiation characteristics.