Depolarisation studies of single trees at 20 GHz

This paper addresses the characterization of the polarization states of the re-radiated signal from a natural tree performed in the vicinity around deep signal fades, at 20 GHz. The polarization pattern method has been used to investigate the effects of depolarization and to further characterize the changes in the polarization state of the re-radiated signal occurring as a result of the currents induced in the trunk, branches and leaves, which are significantly influenced by the complex permittivities of the various materials making up the tree. Results presented in the paper will explain the signal behavior observed in the various regions around the tree. The results also show that depolarization, in addition to absorption and scatter, is an important factor formulating accurate models for propagation in vegetation.