An electromagnetic bandgap curl antenna for phased array applications

A promising way to reduce the problems created by surface waves in printed phased array antennas is to use an electromagnetic bandgap (EBG) substrate instead of a standard dielectric. Two metallo-dielectric EBG substrates well suited for phased array applications have been designed and tested. One of them has a compact unit cell and exhibits a broad bandwidth performance. The other EBG structure has a narrower bandwidth but is simple to manufacture and has a low mechanical profile. Single radiating elements and a small linear array have been manufactured on a standard dielectric substrate and on the EBG substrates. The measurements show a significant improvement in radiation efficiency as well as of the front to back ratio for the antennas manufactured on the EBG substrates compared to the ones obtained for the antennas manufactured on the standard dielectric substrate. These results clearly demonstrate the effectiveness of the EBG substrates in reducing the surface and guided waves.