An electrically small broadband antenna comprises a plurality generalized contrawound toroidal helical antenna elements, each made from a single continuous conductor divided into two length portions each of which are substantially the same length and which have a generalized helical pattern, wherein...http://www.google.fr/patents/US6239760?utm_source=gb-gplus-shareBrevet US6239760 - Contrawound toroidal helical antenna
