Design of the crescent-shape planar ultrawideband antenna with a band-notch structure

A miniaturized crescent-shape planar antenna is proposed for ultra-wideband applications. The proposed antenna consists of a trapezoid ground plane and a crescent-shape radiating patch with a symmetrically circular slot inside the patch. The antenna is fabricated on an FR4 with a thickness of 0.8 mm and the relative permittivity of 4.4. Simulated results show that the return loss (VSWR <; 2) covers the UWB spectrum and the radiation patterns are highly similar to a dipole antenna. To avoid an interference with the present existing bands such as IEEE 802.11a (5.15 GHz-5.825 GHz), UWB systems are required a band-notched feature. Usually, this can be achieved by a band-notched filter integrated with the UWB antenna. In this study, a nested slot band-notched filter is adopted and the filter can block the signal between 5 GHz to 6 GHz. Simulated results such as VSWR, radiation pattern, and current distribution are also described.