UWB antenna design based on modal analysis

In this paper, the theory of characteristic modes is proposed for the analysis and design of UWB planar monopole antennas. This theory provides a very clear insight into the physical performance of this type of antennas. The investigation is focused on the influence of the planar shape in the impedance bandwidth of the antenna, and it will be demonstrated that the impedance bandwidth is extremely dependent on the feeding gap configuration. Moreover, the theory of characteristic modes will be used to analyze UWB antennas with band-notched performance. The information provided by the modal analysis will facilitate the design of band-notched UWB planar monopole antennas, and novel designs will be presented.