A novel compact dual-band monopole antenna using defected ground structure

A novel compact microstrip-fed monopole antenna for wireless application is proposed. Defected ground structure (DGS) is used in this antenna, which has a rectangular patch with dual J-shaped strips, for achieving an additional resonant mode and good impedance matching. The proposed antenna has a small overall size of 20mm×28mm, and operates over the frequency ranges, 2.35-2.75 GHz and 3.3-3.83 GHz suitable for 2.4 GHz WLAN and 2.6/3.5GHz WiMAX communications. Omnidirectional radiation patterns with quite stable gains over the operating bands are obtained, which makes the antenna a good candidate for dual-band wireless communication applications.