Band-reject ultra-wideband monopole antenna using patch loading
Proposed is a new simple technique for achieving band rejection characteristics in ultra-wideband monopole antennas. Two band notches were added to an existing UWB antenna by gluing a padding patch printed on a small single-layer piece of commercial substrate. The design of the new proposed structure has a controllable rejection in the 5 GHz WLAN and 8 GHz ITU frequencies while maintaining a wideband performance from 2.9 GHz to more than 12 GHz based on VSWR <= 2. A good agreement between measurement and simulation was achieved. Measurements confirm that the technique introduces negligible antenna radiation pattern distortion except at the notched frequencies.