Abstract-A novel compact microstrip slot antenna applied to WLAN/WiMAX applications is presented. The proposed antenna consists of a trapezoid and ellipse slot, a pair of symmetrical inverted L-strips, an elliptical-arc-shaped stub and a monopole radiator. By adjusting the dimensions and positions of these structures, the antenna can effectively generate three different resonances to cover the WLAN/WiMAX bands while maintaining small size and simple structure. Based on this concept, a prototype of the proposed antenna has been successfully fabricated and measured. The experimental and numerical results show that the antenna has impedance bandwidth with 10 dB return loss of 360 MHz (2.33-2.69 GHz) and 2630 MHz (3.24-5.87 GHz), which can cover both the WLAN 2.4/5.2/5.8 GHz bands and the WiMAX 2.5/3.5/5.5 GHz bands. In addition, good monopole-like radiation characteristics with sufficient antenna gains are obtained over the operating bands.