A communications system that uses electromagnetic waves. The communications system preferably operates in the millimeter-wave frequencies, and provides relatively high signal restoration and isolation. The communications system can use polarization diversity to increase the capacity of a channel. Isolation...http://www.google.de/patents/US6233435?utm_source=gb-gplus-sharePatent US6233435 - Multi-function interactive communications system with circularly/elliptically polarized signal transmission and reception
