A low-profile Archimedean spiral antenna using an EBG ground plane

This letter presents the implementation of electromagnetic band-gap (EBG) structures with an inherently wide-band Archimedean spiral antenna. The EBG structure is designed to emulate a perfect magnetic conductor. The combination of technologies produces a low-profile and wide-band antenna. Utilization of an EBG structure offers an antenna height reduction of more than 69%, including the thickness of the EBG structure, compared to the traditional /spl lambda//4 cavity backed implementation of spiral antennas. Specifically, this approach allows the spiral antenna to maintain a considerable fraction (71 %) of its designed inherent broad-band behavior with no loss to its directive gain. In addition, the presented design offers full scalability.