Compact wide tri-band slot antenna for WLAN/WiMAX applications

A compact wide tri-band microstrip-fed slot antenna for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) application is presented. Three operating bands are achieved by inserting a pair of T-shaped strips into a wide rectangular slot. The bandwidth enhancement is obtained by introducing a staircase pattern into the wide rectangular slot. A fabricated prototype for the proposed tri-band antenna has compact dimensions of 36 x 30 mm(2), and provides a wide impedance bandwidth. The measured impedance bandwidth for 10dB return loss at 2.5, 3.5, and 5.6 GHz operating band can be up to 540, 940, and 950 MHz, respectively. Moreover, the antenna shows monopole-like radiation patterns and stable antenna gains across the three operating bands.