Archimedean and Equiangular Slot Spiral Antennas for UWB Communications

Archimedean and planar equiangular slot spiral antennas are two candidate geometries with circular polarization for ultra-wideband applications. This paper compares the time domain response of these two kinds of antennas with approximately the same outer radius. The use of a substrate underneath the spiral is used to improve the impedance matching; this also makes the antenna dimensions compatible with portable electronic devices. The Archimedean microstrip antenna has better return loss performance, but the equiangular slot spiral antenna cause less pulse distortion. In UWB communications, the characteristics of antennas in time domain can be of importance. In particular, the cross correlation function between the source signal applied to a transmitting antenna and the output signal from an identical receive antenna have been investigated