Characteristic polarisation states for bistatic nonreciprocal coherent scattering case

To define the characteristic polarisation points of scattering matrices on the Poincare sphere and to arrive at their interesting features, a basic approach to the foundations of polarimetry is first established, together with definitions of fundamental polarimetric quantities. New explanations of these definitions, based on transmission equations, are essential to get broad acceptance of the proposed calculus. Analytical and geometrical methods are presented for determination of the characteristic polarisation points for bistatic nonreciprocal coherent scattering and propagation matrices. The results are summarized and completed with cross-polarisation maximum and saddle points or minimum points.