Millimeter-wave polarimetric measurements of artificial and natural targets

The millimeter-wave polarimeter (MMP), a scatterometer system uses the HP 8510A vector network analyzer for coherent processing of the received signal, provides the polarization and phase measurement capability needed to measure the complete scattering matrix of a given target. A calibration and measurement technique that was used with the MMP at 35 GHz to measure the scattering matrix for both distributed and point targets is described. The measurement accuracy was analyzed by comparing theoretical and measured values for a set of conducting spheres and finite-length conducting cylinders. As an extension of the analysis to natural targets, the scattering matrix was measured for a series of twigs and various smooth and rough surfaces