By Steven I. Biro, Biro Engineering
Since the first experimental circularly polarized TV broadcast started in 1974 (Station WLS-TV, Channel 7, Chicago), the application of CP receiving antennas enjoyed growing interest among CATV engineers and system operators. This presentation is intended as an introduction to the reader on the concept of circular polarization, and will be followed by a review of methods to generate and receive CP electromagnetic waves. The discussion then focuses on the co-channel protection difficulties experienced with CP antenna-arrays, due to amplitude and phase distortions. Representative references are listed at the end of this paper, so the reader may conveniently interrupt this fast guided tour for more detailed studies in selected important topics.