A general characterization of Superdirectivity

This paper presents a general formulation for characterization of any finite antenna as either normal or superdirective. The IEEE Std. 145-2013 defines “Superdirectivity: The condition that occurs when the antenna directivity is significantly higher than that with the array or aperture uniformly excited.” This characterization is evidently limited to the special forms of antennas: uniform array or planar aperture antennas. A survey of several popular antenna textbooks shows that, if the topic is listed in the index at all, they cover substantially nothing of a more general nature.