A comparison of radar, optic, and specular null polarization theories

The fields of radar and optical polarimetry are compared. Both fields have defined scattering matrices that describe the coherent scattering of monochromatic electric fields. This paper compares the mathematics of the two disciplines and it is then shown that Kennaugh´s optimum polarizations can be derived in the context of optical polarimetry, which always employs a local right-handed coordinate system. In addition, a novel definition of the receive copolar polarization state is given: that polarization state that results when a plane wave is reflected by a specular surface. The resulting mathematics when this definition is used in termed specular null polarization theory. It is shown that this new definition facilitates the analysis of backscatterers by focusing on those polarization state changes that are only due to the scatterer