Extended bandwidth monopole antenna with frequency band-stop operation forwireless applications

This letter proposes a new monopole antenna for wireless applications, in particular ultra wideband (UWB) with 3.5/5.5 GHz dual notched bands. The antenna includes square patch, 50 Ω microstrip feed-line, and a partial ground plane using a new structure provides a broad impedance bandwidth. In order to achieve dual notched bands at 3.5 GHz and 5.5 GHz, two radiating strips and a T-shaped slot on the radiating patch are applied, respectively. The antenna is simple in geometry and has a small size of 19∼14 mm2. The measured results show a desirable agreement with the simulated results. The antenna approximately produces omnidirectional radiation patterns in Hplane, and flat gain over the whole UWB frequency excluding the two notched bands (WiMAX and WLAN bands).