EBG Focal Feed Design Optimization

Recent works have shown that the electromagnetic bandgap (EBG) antenna can be used as a reflector focal feed. The design of such feeds needs to take into account several parameters to obtain both high illumination performances and low reflector antenna side-lobe level. Among these EBG antenna parameters, the quality factor, the excitation probe used and the phase center location constitutes key elements to obtain high performances. This article presents useful design curves to conceive an efficient EBG focal feed. These curves have been used to realize a 30-GHz single-feed EBG device illuminating a side-fed offset Cassegrain antenna (SFOCA). Results show good performances in terms of aperture efficiency and radiation patterns of the reflector antenna compared to the Potter horn previously used with the same reflector.