Polarimetric Backscatter Measurements of Deciduous and Coniferous Trees at 225GHz

摘要

This paper describes the first polarimetric radar measurements of foliage made inthe 220 GHz transmission window. A noncoherent, 60 W peak-power polarimetric radar was used to directly measure the target Mueller matrix by measuring the scattered polarization state for either four or six incident polarizations. Measurements of deciduous trees indicate that waves scattered from erectophil trees (vertically oriented leaves) are more highly polarized than waves scattered from planophil trees (horizontally oriented leaves) for near-grazing incidence angles. White Pine trees, which have thin needles, were the least polarized of all trees studied. A comparison of the Mueller matrices of 11 independent footprints taken from 7 White Pine trees showed a high degree of consistency between measurements.