Planar Dual U-Shaped Monopole Antenna With Multiband Operation for IEEE 802.16e

A novel compact design of a planar dual U-shaped monopole antenna with multiband operation for the IEEE 802.16e Worldwide Interoperability for Microwave Access (WiMAX) system is proposed. With the use of dual U-shaped monopole strips, multiresonant modes close to 2.6/3.5/5.5-GHz band are excited to meet the specifications of the WiMAX system (IEEE 802.16e) . 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. 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. 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, with nearly omnidirectional pattern in the xy plane.