Evaluation of Scattering by Spacecrafts Using Characteristic Mode Theory Considering Ionosphere Faraday Effect

This article is concerned with developing a viable procedure to evaluate the scattering property of a satellite object. First, to deal with the uncertainty of attitudes of the object with respect to the direction of incidence, the characteristic mode theory is exploited, which is independent of the incident waves. The total scattered field is obtained by summing up the individual characteristic scattered fields with modal weighting coefficients. Second, the ionosphere Faraday effect that may significantly change the polarization behaviors is considered when the frequency is at L-band or below for a ground-based identifying radar. The ionosphere is taken as a sparse and weakly magnetized plasma, and the approximate Wentzel–Kramers–Brillouin method is adopted to calculate the propagations of two intrinsic modes through the ionosphere. The Stokes vector is assumed to be the measured quantities, and the Mueller matrix is employed to fully describe the polarized scattering process.