Planar multi-band monopole antenna for WLAN/WiMAX applications

A novel compact design of planar multi-band monopole antenna for WLAN/WiMAX system is proposed. By insetting a pair of mirrored L-shaped monopole strips, multi resonant modes close to 2.45/3.5/5.5 GHz band are excited to meet the specifications of WLAN/WiMAX system. The obtained impedance bandwidth across the operating bands can reach about 160/1100/2690 MHz for the 2.45/3.5/5.5 GHz bands, respectively. Only with the antenna size of 30 × 42 × 0.8 mm
³
, the proposed monopole antenna has the compact operation with more than 20% antenna size reduction. The measured peak gains and radiation efficiencies are about 3.2/3.5/5.4 dBi and 72/98/96% for the 2.45/3.5/5.5 GHz band, respectively, with nearly omni-directional pattern in the XY-plane.