Study of the band-notched functions for CPW-fed UWB antenna

Compact single-layer coplanar waveguide (CPW) fed monopole UWB antennas with dual frequency band-notched functions are presented. By etching two L-slots in the ground plane of the CPW, a stopband of 3.3 to 4.2 GHz is achieved. To obtain another stopband (5.2 to 6.1 GHz) for band rejection of WLAN, two kinds of designs are proposed: inserting a U-shaped slot or attaching a tuning stub into the radiating ring. The effects of the lengths of the slots and stub on the notched frequency bands are analyzed. The antenna is successfully simulated, designed, and measured, showing stable gains, omnidirectional radiation patterns and super-wideband function from 2.5 to 12 GHz except two notched band.