Hybrid-Quad-Pol SAR

Data products from a quadrature-polarized synthetic aperture radar (SAR) are fully characterized by Stokes parameters. It follows that choice of the polarization basis of either the transmitted or the received EM fields has no impact on the measurement potential of the system. Hence the polarization plan for a quad-pol SAR can be selected to optimize the radar´s engineering performance. The logical conclusion is that an optimal quad-pol radar should transmit circular polarization, and receive orthogonal linear polarizations. This paper shows that there is no loss in SNR on any polarization combination in the quad-pol data products as a result of this architecture, which is a more robust result than is true for a hybrid-dual-pol radar, in which SNR preservation is true if and only if the output polarization basis is chosen to match the input (circular) basis.