Polarization characteristics of coherent waves

Analytic representations of coherent-wave polarization draw from well-known physics in this subject as applied to electromagnetic problems, and especially antennas. However, the physical visualization, bases, and their interrelationships are frequently from disparate sources. The increasing use of multi-function phased arrays highlights other topics of concern, since the changing directions of steered beams results in dynamic changes in polarization that must be dealt with. Following basic visualization in terms of circular basis components, the circular-to-linear basis-transform matrices are derived. Since similarities or interactions among different polarizations are concerned, the physical and analytic utility of the Poincaré sphere is reviewed. Geometric effects inherently basic to all phased array problems are demonstrated and analyzed in connection with polarization control. Cross-polarization interpretation and association with pattern measurements are described.