Design of a quasi-hemispherical UWB antenna

Abstract

This paper proposes a design of three-dimensional antenna for ultrawideband applications. The antenna has dimensions of 58 mm x 58 mm x 76.5 mm and is composed of two identical arms. Each arm consists of a hollow quasi-hemisphere and an inner for it tube. In the simulation, a 50 Ω coaxial cable is employed to feed the antenna in order to assess the change of the antenna performance due to the cable effect. The simulated results show that the antenna is capable of operating in the frequency band from 7 to 32.5 GHz with S11 below-10 dB, while maintaining an omnidirectional radiation pattern. The simulated total efficiency is above 88 % over the entire impedance bandwidth which indicates a good antenna performance. The realized gain varies from 0.8 to 3.1 dBi with frequency.