Reducing Ground-Plane Effects on UWB Monopole Antennas

A common problem with planar ultrawideband (UWB) monopole antennas is that their performance is heavily affected by the ground plane. To resolve this problem, a novel approach is proposed in this letter. Slots along the top edge of the ground are introduced to minimize the ground-plane effects by changing the current distribution. An equivalent circuit model is developed to obtain an insight view of the behavior of the slots. Computer simulation and measured results are obtained, and they confirm the validity of the proposed method.