A novel archimedean spiral antenna with uniplanar EBG substrate

A gap-loading Archimedean spiral antenna with uniplanar EBG is presented in this paper. Utilization of the gap-loading technique offers an antenna lowest operation frequency reduction of more than 0.5 GHz. The uniplanar EBG is of benefit to reduce the height about 60%, including the thickness of EBG structure, compare to the traditional lambda/4 cavity backed implementation of Archimedean spiral antenna. Further investigations indicate that the radiation patterns and 3 dB angular width are both stable in the range of 2 GHz-5 GHz.