A Novel UWB Monopole Antenna with Controllable Band-Notch Characteristics

─ A novel microstrip monopole antenna for Ultra Wide Band applications with switchable bandnotch function is presented. For this purpose, elliptical radiator and a half circular shape ground plane are modified. Using these modifications, including a rectangular and an arc-shaped slots on ground plane and a complex form of slot, etched on the patch, new resonances are excited and hence bandwidth is enhanced. In addition, by adding one rectangular step to patch, wide fractional bandwidth of more than 124% (2.7-11.61 GHz), defined by 10 dB return loss is achieved, in following part effects of the rectangular step is investigated. The rejection of 3.01-3.9 GHz, WiMAX and 5.07-6 GHz, WLAN bands is achieved using small connections as switches across the circular slot and rectangular arm on the radiation patch in specific positions. The total size of antenna is only 21×26 mm. Parametric simulation of the proposed modifications and measurement results of the manufactured antenna are presented and discussed. Index Terms ─ Frequency band-notched, microstrip-fed monopole antenna, switches, Ultra Wide Band (UWB).