A triple-band unidirectional coplanar antenna for 2.4/3.5/5-GHz WLAN/WiMax applications

A triple-band unidirectional coplanar antenna is developed for WLAN/WiMax wireless applications. The triple-band planar antenna consists of a top-loaded dipole for the 2.4-GHz band, two longer dipoles for 3.5-GHz band, and 2 shorter dipoles for the 5-GHz band. The triple-band antenna is printed on a coplanar substrate. The antenna achieves a similar directional radiation pattern at all of the three frequency bands with gains of 7.5 dBi for the lowest band, 8.5 dBi for the middle band, and 9-10 dBi for the highest band.