Polarimetric observations of trees at 35 and 94 GHz

Two different kinds of trees were measured with a newly developed polarimetric radar at 35 and 94 GHz. The first was a rhododendron with a planophil leaf orientation distribution and an average leaf area of 40 cm/sup 2/; the second was a spruce blue shiner with a uniform leaf orientation distribution and an average needle length of 1.5 cm. The system is based on the coherent-on-receive technique and is capable of measuring the Mueller matrix directly. The degree of polarization, phase statistics, and polarization signatures are presented. Results show that the degree of polarization is sensitive to the radar frequencies and tree types.<>