A planer sinuous antenna and the relevant balun

Abstract

In this paper, a planar four-arm sinuous antenna for 2-18GHz and its balun have been studied and designed. The balun, matched the balance structure and the wideband character of the antenna, is microstrip exponential gradual tapered type. The simulation result shows that the VSWR over the frequency band is less than 2. The antenna has good circular polarization performance and for the entire frequency band, the axial ratio can be kept below 3 dB.