Dual-band ESPAR antenna for wireless LAN applications

A 2.4/5.2 GHz dual-band ESPAR (electronically steerable parasitic array radiator) antenna has been developed. The antenna consists of one RF excited center element and six parasitic ones for each frequency band. Each parasitic element is connected to a ground plane via variable reactance for controlling the beam direction. In order to avoid the beam fluctuations of the 5.2 GHz-band being affected by the 2.4 GHz beam, a low pass filter is added between parasitic element for 2.4 GHz-band and variable reactance. Six short posts are arranged symmetrically close to the center element to achieve a dual band resonance. This is the first report showing the successful dual-band operation of ESPAR antenna.