Techniques to improve ultra wide band performance of planar monopole antenna

Impedance characteristics of a group of ultra-wideband (UWB) antennas with different geometries are theoretically and experimentally studied. Significant improvements on the upper band frequency impedance bandwidth are observed due to the additional antenna geometry modification at the upper side of the antenna. It shows that the higher frequency range of impedance bandwidth can be improved by tuning the top part of the antenna simultaneously with the same geometry modification at the lower part of the antenna. The simulated radiation patterns are also shown as well. The details of the simulation and experiment results are presented and discussed.