Novel design of planar multi-band u-shaped monopole antenna with compact operation for WiMAX application

A novel compact design of planar dual U-shaped monopole antenna with multi-band operation for IEEE 802.16e WiMAX system is proposed. With the use of dual U-shaped monopole strips, multi resonant modes close to 2.6 / 3.5 / 5.5 GHz band are excited to meet the specifications of WiMAX system (IEEE 802.16e). And, the obtained impedance bandwidth across the operating bands can reach about 220 / 1660 / 1480 MHz for the 2.6 / 3.5 / 5.5 GHz bands, respectively. With nearly omni-directional pattern in the XY-plane, the measured peak gains and radiation efficiencies are about 3.5 / 4.1 / 5.5 dBi and 68 / 66 / 95% for the 2.6 / 3.5 / 5.5 GHz band, respectively. Only with the antenna size of 25 × 30 × 0.8 mm
³
, the proposed monopole antenna has the compact operation with more than 35% antenna size reduction.